-page.title=Common Tasks and How to Do Them in Android
-parent.title=FAQs, Tips, and How-to
-parent.link=index.html
@jd:body
-<ul>
- <li><a href="#neweclipseandroidproject">Creating an Android Application using
- the Eclipse plugin</a></li>
- <li><a href="#newandroidprojectnoeclipse">Creating an Android Application without
- the Eclipse plugin</a></li>
- <li><a href="#addexternallibrary">Adding an External Library (.jar) using Eclipse</a></li>
- <li><a href="#implementcallbacks">Implementing Activity callbacks</a> (Android
- calls your activity at various key moments in its life cycle. You must know
- how to handle each of these to draw your screen, initialize class members,
- and acquire data.)</li>
- <li><a href="#opennewscreen">Opening a new screen</a></li>
- <li><a href="#listening">Listening for button clicks </a></li>
- <li><a href="#configurewindowproperties">Configuring general window properties </a></li>
- <li><a href="#localhostalias">Referring to localhost from the emulated environment</a></li>
- <li><a href="#appstate">Storing and retrieving state</a></li>
- <li><a href="{@docRoot}guide/topics/data/data-storage.html#preferences">Storing and retrieving preferences</a></li>
- <li><a href="#storingandretrieving">Storing and retrieving larger or more complex
- persistent data</a> (files and data) </li>
- <li><a href="#playback">Playing audio, video, still, or other media files</a></li>
- <li><a href="#broadcastreceivers">Listening for and broadcasting global messages
- and setting alarms</a></li>
- <li><a href="#alerts">Displaying alerts </a></li>
- <li><a href="#progressbar">Displaying a progress bar</a> </li>
- <li><a href="#addmenuitems">Adding items to the screen menu</a> </li>
- <li><a href="#webpage">Display a web page</a> </li>
- <li><a href="#binding">Binding to data</a></li>
- <li><a href="#handle">Getting a Handle to a Screen Element</a></li>
- <li><a href="#captureimages">Capture images from the phone camera </a></li>
- <li><a href="#threading">Handling expensive operations in the UI thread</a></li>
- <li><a href="#selectingtext">Selecting, highlighting, or styling portions of
- text</a></li>
- <li><a href="#querymap">Utilizing attributes in a Map query</a></li>
- <li><a href="#filelist">List of files for an Android application</a></li>
- <li><a href="#logging">Print messages to a log file</a></li>
-</ul>
-<p>The ApiDemos sample application includes many, many examples of common
-tasks and UI features. See the code inside
-<code><sdk>samples/ApiDemos</code> and the other sample applications
-under the <code>samples/</code> folder in the SDK.</p>
-
-
-<h2 id="neweclipseandroidproject">Creating an Android Application using the Eclipse Plugin</h2>
-
-<p>Using the Android Eclipse plugin is the fastest and easiest way
-to start creating a new Android application. The plugin automatically generates
-the correct project structure for your application, and keeps the resources
-compiled for you automatically.</p>
-
-<p>It is still a good idea to know what is going on though. Take a look at <a
-href="{@docRoot}guide/topics/fundamentals.html">Application Fundamentals</a>
-to understand the basics of how an Android application works.</p>
-
-<p>You should also take a look at the ApiDemos application and the other sample
-applications included in the SDK, in the <code><sdk>/samples/</code>
-folder in the SDK.</p>
-
-<p>Finally, a great way to started with Android development in Eclipse is to
-follow both the <a href="{@docRoot}resources/tutorials/hello-world.html">Hello,
-World</a> and <a
-href="{@docRoot}resources/tutorials/notepad/index.html">Notepad</a> code
-tutorials. In particular, the start of the Hello Android tutorial is an
-excellent introduction to creating a new Android application in Eclipse.</p>
-
-<h2 id="newandroidprojectnoeclipse">Creating an Android Application without the Eclipse Plugin</h2>
-
-<p>This topic describes the manual steps in creating an Android application.
-Before reading this, you should read <a
-href="{@docRoot}guide/topics/fundamentals.html">Application Fundamentals</a>
-to understand the basics of how an Android application works. You might also
-want to look at the sample code included with the Android SDK, in the
-<code><sdk>/samples/</code> directory. </p>
-
-<p>Here is a list of the basic steps in building an application.</p>
-<ol>
- <li><strong>Create your required resource files</strong> This includes
- the AndroidManifest.xml global description file, string files that your application
- needs, and layout files describing your user interface. A full list of optional
- and required files and syntax details for each is given in <a href="#filelist">File
- List for an Android Application</a>. </li>
- <li><strong>Design your user interface</strong> See <a
- href="{@docRoot}guide/topics/ui/index.html">User Interface</a> for
- details on elements of the Android screen. </li>
- <li><strong>Implement your Activity </strong>(this page)<strong> </strong> You
- will create one class/file for each screen in your application. Screens will
- inherit from an {@link android.app android.app} class, typically {@link android.app.Activity
- android.app.Activity} for basic screens, {@link android.app.ListActivity
- android.app.ListActivity} for list screens, or {@link android.app.Dialog
- android.app.Dialog} for dialog boxes. You will implement the required callbacks
- that let you draw your screen, query data, and commit changes, and also perform
- any required tasks such as opening additional screens or reading data from
- the device. Common tasks, such as opening a new screen or reading data from
- the device, are described below.
- The list of files you'll need for your application are described in <a href="#filelist">List
- of Files for an Android Application</a>. </li>
- <li><strong><a href="{@docRoot}guide/developing/other-ide.html#buildingwithant">Build and install your
- package</a>.</strong> The Android SDK has some nice tools for generating
- projects and debugging code. </li>
-</ol>
-
-<h2 id="addexternallibrary">Adding an External Library (.jar) using Eclipse</h2>
-<p>
-You can use a third party JAR in your application by adding it to your Eclipse project as follows:
-</p>
-<ol>
-<li>
-In the <strong>Package Explorer</strong> panel, right-click on your project and select <strong>Properties</strong>.
-<li>
-Select <strong>Java Build Path</strong>, then the tab <strong>Libraries</strong>.
-<li>
-Press the <strong>Add External JARs...</strong> button and select the JAR file.
-</ol>
-<p>
-Alternatively, if you want to include third party JARs with your package, create a new directory for them within your project and select <strong>Add Library...</strong> instead.</p>
-<p>
-It is not necessary to put external JARs in the assets folder.
-</p>
-
-<a name="implementcallbacks" id="implementcallbacks"></a>
-<h2>Implementing Activity Callbacks</h2>
-<p>Android calls a number of callbacks to let you draw your screen, store data before
- pausing, and refresh data after closing. You must implement at least some of
- these methods. See the <a
-href="{@docRoot}guide/topics/fundamentals/activites.html#Lifecycle">Activities</a>
- document to learn when and in what order these methods
- are called. Here are some of the standard types of screen classes that Android provides:</p>
-<ul>
- <li>{@link android.app.Activity android.app.Activity} - This is a standard screen,
- with no specialization.</li>
- <li>{@link android.app.ListActivity android.app.ListActivity} - This is a screen
- that is used to display a list of something. It hosts a ListView object,
- and exposes methods to let you identify the selected item, receive callbacks
- when the selected item changes, and perform other list-related actions. </li>
- <li>{@link android.app.Dialog android.app.Dialog} - This is a small, popup dialog-style
- window that isn't intended to remain in the history stack. (It is not resizeable
- or moveable by the user.)</li>
-</ul>
-
-<a name="opennewscreen" id="opennewscreen"></a><h2>Opening a New Screen</h2>
-<p>Your Activity will often need to open another Activity screen as it progresses.
- This new screen can be part of the same application or part of another application,
- the new screen can be floating or full screen, it can return a result, and you
- can decide whether to close this screen and remove it from the history stack
- when you are done with it, or to keep the screen open in history. These next
- sections describe all these options. </p>
-<h3>Floating or full?<a name="floatingorfull" id="floatingorfull"></a></h3>
-<p>When you open a new screen you can decide whether to make it transparent or floating,
- or full-screen. The choice of new screen affects the event sequence of events
- in the old screen (if the new screen obscures the old screen, a different
- series of events is called in the old screen). See the <a
- href="{@docRoot}guide/topics/fundamentals/activities.html#Lifecycle">Activities</a> document for
-details. </p>
-<p>Transparent or floating windows are implemented in three
- standard ways: </p>
-<ul>
- <li>Create an {@link android.app.Dialog app.Dialog} class </li>
- <li>Create an {@link android.app.AlertDialog app.AlertDialog} class </li>
- <li>Set the {@link android.R.style#Theme_Dialog} <em>theme</em> attribute to <code>@android:style/Theme.Dialog</code>
- in your AndroidManifest.xml file. For example:
- <pre><activity class="AddRssItem" android:label="Add an item" android:theme="@android:style/Theme.Dialog"/>
-</pre></li>
-</ul>
-<p>Calling startActivity() or startActivityForResult() will open a new screen in whatever
- way it defines itself (if it uses a floating theme it will be floating,
- otherwise it will be full screen). </p>
-<h3>Opening a Screen </h3>
-<p>When you want to open a new screen, you can either explicitly specify the activity
- class to open, or you can let the operating system decide which screen to open,
- based upon the data and various parameters you pass in. A screen is opened by
- calling {@link android.app.Activity#startActivity(android.content.Intent) startActivity}
- and passing in an {@link android.content.Intent Intent} object, which specifies
- the criteria for the handling screen. To specify a specific screen, call Intent.setClass
- or setClassName with the exact activity class to open. Otherwise, set a variety
- of values and data, and let Android decide which screen is appropriate to open.
- Android will find one or zero Activities that match the specified requirements;
- it will never open multiple activities for a single request. More information
- on Intents and how Android resolves them to a specific class is given in the
- {@link android.content.Intent Intent} topic. </p>
-<a name="intentexamples" id="intentexamples"></a><h3>Some Intent examples </h3>
-<p>The following snippet loads the com.android.samples.Animation1 class, and
- passes it some arbitrary data.:</p>
-<pre>Intent myIntent = new Intent();
-myIntent.setClassName("com.android.samples", "com.android.samples.Animation1");
-myIntent.putExtra("com.android.samples.SpecialValue", "Hello, Joe!"); // key/value pair, where key needs current package prefix.
-startActivity(myIntent); </pre>
-<p>The next snippet requests that a Web page be opened by specifying the VIEW action,
- and a URI data string starting with "http://" schema:</p>
-<pre>Intent myIntent = new Intent(Intent.VIEW_ACTION, Uri.parse("http://www.google.com"));</pre>
-<p>Here is the intent filter from the AndroidManifest.xml file for com.android.browser:</p>
-<pre><intent-filter>
- <action android:name="android.intent.action.VIEW" />
- <category android:name="android.intent.category.DEFAULT" />
- <scheme android:name="http" />
- <scheme android:name="https" />
- <scheme android:name="file" />
-</intent-filter> </pre>
-<p>Android defines a number of standard values, for instance the action constants
- defined by {@link android.content.Intent}. You can define custom values, but
- both the caller and handler must use them. See the <intent-filter>
- tag description in <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">The AndroidManifest.xml
- File</a> for more information on the manifest syntax for the handling
- application. </p>
-<a name="returningaresult" id="returningaresult"></a><h3>Returning a Result from a Screen</h3>
-<p>A window can return a result after it closes. This result will be passed back
- into the calling Activity's {@link android.app.Activity#onActivityResult(int,int,android.content.Intent)
- onActivityResult()} method, which can supply an Intent containing arbitrary data, along with
- the request code passed to startActivityForResult(). Note that you must call the {@link
- android.app.Activity#startActivityForResult(android.content.Intent,int) startActivityForResult()}
- method that accepts a request code parameter to get this callback. The following
- code demonstrates opening a new screen and retrieving a result. </p>
-<pre>// Open the new screen.
-public void onClick(View v){
- // Start the activity whose result we want to retrieve. The
- // result will come back with request code GET_CODE.
- Intent intent = new Intent(this, com.example.app.ChooseYourBoxer.class);
- startActivityForResult(intent, CHOOSE_FIGHTER);
-}
-
-// Listen for results.
-protected void onActivityResult(int requestCode, int resultCode, Intent data){
- // See which child activity is calling us back.
- switch (resultCode) {
- case CHOOSE_FIGHTER:
- // This is the standard resultCode that is sent back if the
- // activity crashed or didn't doesn't supply an explicit result.
- if (resultCode == RESULT_CANCELED){
- myMessageboxFunction("Fight cancelled");
- }
- else {
- myFightFunction(data);
- }
- default:
- break;
- }
-}
-
-// Class SentResult
-// Temporary screen to let the user choose something.
- private OnClickListener mLincolnListener = new OnClickListener(){
- public void onClick(View v) {
- Bundle stats = new Bundle();
- stats.putString("height","6\'4\"");
- stats.putString("weight", "190 lbs");
- stats.putString("reach", "74\"");
- setResult(RESULT_OK, "Lincoln", stats);
- finish();
- }
- };
-
- private OnClickListener mWashingtonListener = new OnClickListener() {
- public void onClick(View v){
- Bundle stats = new Bundle();
- stats.putString("height","6\'2\"");
- stats.putString("weight", "190 lbs");
- stats.putString("reach", "73\"");
- setResult(RESULT_OK, "Washington", Bundle);
- finish();
- }
- };
- </pre>
-<h3>Lifetime of the new screen </h3>
-<p>An activity can remove itself from the history stack by calling {@link android.app.Activity#finish()
- Activity.finish()} on itself, or the activity that opened the screen can call
- {@link android.app.Activity#finishActivity(int) Activity.finishActivity()}
- on any screens that it opens to close them. </p>
-<a name="listening" id="listening"></a><h2>Listening for Button Clicks</h2>
-<p>Button click and other UI event capturing are covered in <a href="{@docRoot}guide/topics/ui/ui-events.html">Handling UI Events</a> on the UI Design page.</p>
-<a name="configurewindowproperties" id="configurewindowproperties"></a><h2>Configuring General Window Properties</h2>
-<p>You can set a number of general window properties, such as whether to display
- a title, whether the window is floating, and whether it displays an icon, by
- calling methods on the {@link android.view.Window Window} member
- of the underlying View object for the window. Examples include calling {@link
- android.app.Activity#getWindow() getWindow().requestFeature()} (or the convenience
- method {@link android.app.Activity#requestWindowFeature(int) requestWindowFeature(<em>some_feature</em>)})
- to hide the title. Here is an example of hiding the title bar:</p>
-<pre>//Hide the title bar
-requestWindowFeature(Window.FEATURE_NO_TITLE);
-</pre>
-<p>A better way to achieve the same end is to specify a theme in your Android
-Manifest file:</p>
-<pre><application android:icon="@drawable/icon" android:theme="@android:style/Theme.NoTitleBar">
-</pre>
-<p>This is preferable because it tells the system not to show a title bar while
-your application is starting up. With the explicit method call, your application
-will have a title bar visible to the user until <code>onCreate</code> runs.</p>
-<p>(Note that this can be applied to either the <code><application></code>
-tag or to individual <code><activity></code> tags.)</p>
-<a name="localhostalias" id="localhostalias"></a><h2>Referring to localhost from the emulated environment</h2>
-<p>
-If you need to refer to your host computer's <em>localhost</em>, such as when you
-want the emulator client to contact a server running on the same host, use the alias
-<code>10.0.2.2</code> to refer to the host computer's loopback interface.
-From the emulator's perspective, localhost (<code>127.0.0.1</code>) refers to its own
-loopback interface.
-</p>
-<a name="appstate" id="appstate"></a><h2>Storing and Retrieving State</h2>
-<p>If your application is dumped from memory because of space concerns, it will lose
- all user interface state information such as checkbox state and text box values
- as well as class member values. Android calls {@link android.app.Activity#onSaveInstanceState(android.os.Bundle)
- Activity.onSaveInstanceState} before it pauses the application. This method hands in a {@link
- android.os.Bundle Bundle} that can be used to store name/value pairs that will
- persist and be handed back to the application even if it is dropped from memory.
- Android will pass this Bundle back to you when it calls {@link android.app.Activity#onCreate(android.os.Bundle)
- onCreate()}. This Bundle only exists while the application is still in the history
- stack (whether or not it has been removed from memory) and will be lost when
- the application is finalized. See the topics for {@link android.app.Activity#onSaveInstanceState} and
- {@link android.app.Activity#onCreate} for
- examples of storing and retrieving state.</p>
-<p>Read more about the lifecycle of an activity in <a
-href="{@docRoot}guide/topics/fundamentals/activities.html">Activities</a> document.</p>
-<h3>Storing and Retrieving Larger or More Complex Persistent Data<a name="storingandretrieving" id="storingandretrieving"></a></h3>
-<p>Your application can store files or complex collection objects, and reserve them
- for private use by itself or other activities in the application, or it can expose
- its data to all other applications on the device. See <a href="{@docRoot}guide/topics/data/data-storage.html">Storing,
- Retrieving, and Exposing Data</a> to learn how to store and retrieve private data,
- how to store and retrieve common data from the device, and how to expose your
- private data to other applications.</p>
-<a name="playback" id="playback"></a><h2>Playing Media Files</h2>
-<p>Please see the document <a href="{@docRoot}guide/topics/media/index.html">Audio and Video</a> for more details.</p>
-<a name="broadcastreceivers" id="broadcastreceivers"></a><h2>Listening For and Broadcasting Global Messages, and Setting Alarms</h2>
-<p>You can create a listening class that can be notified or even instantiated whenever
- a specific type of system message is sent.
-</p>
-<p>The listening classes, called broadcast receivers, extend {@link android.content.BroadcastReceiver
- BroadcastReceiver}. If you want Android to instantiate the object whenever an appropriate
- intent notification is sent, define the receiver with a <code><receiver></code> element
- in the AndroidManifest.xml file. If the caller is expected to instantiate the
- object in preparation to receive a message, this is not required. The receiver
- will get a call to their {@link android.content.BroadcastReceiver#onReceive(android.content.Context,android.content.Intent)
- BroadcastReceiver.onReceive()} method. A receiver can define an <code><intent-filter></code> tag
- that describes the types of messages it will receive. Just as Android's IntentResolver
- will look for appropriate Activity matches for a startActivity() call, it will
- look for any matching Receivers (but it will send the message to all matching
- receivers, not to the "best" match). </p>
-<p>To send a notification, the caller creates an {@link android.content.Intent Intent}
- object and calls {@link android.app.Activity#sendBroadcast(android.content.Intent)
- Context.sendBroadcast()} with that Intent. Multiple recipients can receive
- the same message. You can broadcast an Intent message to an intent receiver in
- any application, not only your own. If the receiving class is not registered
- using <code><receiver></code> in its manifest, you can dynamically instantiate
- and register a receiver by calling {@link android.content.Context#registerReceiver(android.content.BroadcastReceiver,android.content.IntentFilter)
- Context.registerReceiver()}. </p>
-<p>Receivers can include intent filters to specify what kinds of intents they are
- listening for. Alternatively, if you expect a single known caller to contact
- a single known receiver, the receiver does not specify an intent filter, and
- the caller specifies the receiver's class name in the Intent by calling {@link
- android.content.Intent#setClassName(java.lang.String, java.lang.String) Intent.setClassName()}
- with the recipient's class name. The recipient receives a {@link android.content.Context
- Context} object that refers to its own package, not to the package of the sender.</p>
-<p><em><strong>Note:</strong></em> If a receiver or broadcaster
- enforces permissions, your application might need to request permission
- to send or receive messages from that object. You can request permission by using
- the <uses-permission> tag in the manifest. </p>
-<p>Here is a code snippet of a sender and receiver. This example does not demonstrate
- registering receivers dynamically. For a full code example, see the AlarmService
- class in the ApiDemos project.</p>
-<h3>Sending the message</h3>
-<pre>// We are sending this to a specific recipient, so we will
-// only specify the recipient class name.
-Intent intent = new Intent(this, AlarmReceiver.class);
-intent.putExtra("message","Wake up.");
-sendBroadcast(intent);
-</pre>
-<h3>Receiving the message</h3>
-<p><strong>Receiver AndroidManifest.xml </strong>(because there is no intent filter
- child, this class will only receive a broadcast when the receiver class is specified
- by name, as is done in this example):</p>
-<pre>
-<receiver class=".AlarmReceiver" /></pre>
-<p><strong>Receiver Java code: </strong></p>
-<pre>
-public class AlarmReceiver extends BroadcastReceiver{
- // Display an alert that we've received a message.
- @Override
- public void onReceive(Context context, Intent intent){
- // Send a text notification to the screen.
- NotificationManager nm = (NotificationManager)
- context.getSystemService(Context.NOTIFICATION_SERVICE);
- nm.notifyWithText(R.id.alarm,
- "Alarm!!!",
- NotificationManager.LENGTH_SHORT,
- null);
- }
-} </pre>
-<h3>Other system messages</h3>
-<p>You can listen for other system messages sent by Android as well, such as USB
- connection/removal messages, SMS arrival messages, and timezone changes. See
- {@link android.content.Intent} for a list of broadcast messages to listen for.
- Messages are marked "Broadcast Action" in the documentation. </p>
-<h3>Listening for phone events<a name="phoneevents" id="phoneevents"></a></h3>
-<p>The {@link android.telephony android.telephony} package overview page describes how to
- register to listen for phone events. </p>
-<a name="alarms" id="alarms"></a><h3>Setting Alarms </h3>
-<p>Android provides an {@link android.app.AlarmManager AlarmManager} service that
- will let you specify an Intent to send at a designated time. This intent is typically
- used to start an application at a preset time. (Note: If you want to send
- a notification to a sleeping or running application, use {@link android.os.Handler
- Handler} instead.)</p>
-<a name="alerts" id="alerts"></a><h2>Displaying Alerts</h2>
-<p>There are two major kinds of alerts that you may display to the user:
-(1) Normal alerts are displayed in response to a user action, such as
-trying to perform an action that is not allowed. (2) Out-of-band alerts,
-called notifications, are
-displayed as a result of something happening in the background, such as the
-user receiving new e-mail.</p>
-
-<a name="dialogsandalerts" id="dialogsandalerts"></a><h3>Normal Alerts</h3>
-
-<p>Android provides a number of ways for you to show popup notifications to your
- user as they interact with your application. </p>
-<table width="100%" border="1">
- <tr>
- <th scope="col">Class</th>
- <th scope="col">Description</th>
- </tr>
- <tr>
- <td>{@link android.app.Dialog app.Dialog}</td>
- <td>A generic floating dialog box with a layout that you design. </td>
- </tr>
- <tr>
- <td><p>{@link android.app.AlertDialog app.AlertDialog}</p></td>
- <td>A popup alert dialog with two buttons (typically OK and Cancel) that
- take callback handlers. See the section after this table for more details. </td>
- </tr>
- <tr>
- <td>{@link android.app.ProgressDialog ProgressDialog} </td>
- <td>A dialog box used to indicate progress of an operation with a known progress
- value or an indeterminate length (setProgress(bool)). See <strong>Views</strong> > <strong>Progress Bar</strong> in
- ApiDemos for examples. </td>
- </tr>
- <tr>
- <td>Activity</td>
- <td>By setting the theme of an activity to
- {@link android.R.style#Theme_Dialog
- android:theme="@android:style/Theme.Dialog"},
- your activity will take on
- the appearance of a normal dialog, floating on top of whatever was
- underneath it. You usually set the theme through the
- {@link android.R.attr#theme android:theme} attribute in your AndroidManifest.xml.
- The advantage of this
- over Dialog and AlertDialog is that Application has a much better managed
- life cycle than dialogs: if a dialog goes to the background and is killed,
- you cannot recapture state, whereas Application exposes a {@link android.os.Bundle
- Bundle} of saved values in <code>onCreate()</code> to help you maintain state.</td>
- </tr>
-</table>
-<h3>AlertDialog</h3>
-<p>This is a basic warning dialog box that lets you configure a message, button text,
- and callback. You can create one by calling using the {@link
- android.app.AlertDialog.Builder} class, as shown here. </p>
-<pre>private Handler mHandler = new Handler() {
- public void handleMessage(Message msg) {
- switch (msg.what) {
- case ACCEPT_CALL:
- answer(msg.obj);
- break;
-
- case BOUNCE_TO_VOICEMAIL:
- voicemail(msg.obj);
- break;
-
- }
- }
-};
-
-
-private void IncomingMotherInLawCall(Connection c) {
- String Text;
-
- // "Answer" callback.
- Message acceptMsg = Message.obtain();
- acceptMsg.target = mHandler;
- acceptMsg.what = ACCEPT_CALL;
- acceptMsg.obj = c.getCall();
-
- // "Cancel" callback.
- final Message rejectMsg = Message.obtain();
- rejectMsg.target = mHandler;
- rejectMsg.what = BOUNCE_TO_VOICEMAIL;
- rejectMsg.obj = c.getCall();
-
- new AlertDialog.Builder(this)
- .setMessage("Phyllis is calling")
- .setPositiveButton("Answer", acceptMsg)
- .setOnCancelListener(new OnCancelListener() {
- public void onCancel(DialogInterface dialog) {
- rejectMsg.sendToTarget();
- }});
- .show();
-} </pre>
-
-<h3>Notifications</h3>
-
-<p>Out-of-band alerts should always be displayed using the
-{@link android.app.NotificationManager}, which allows you to tell the user
-about something they may be interested in without disrupting what they are
-currently doing. A notification can be anything from a brief pop-up box
-informing the user of the new information, through displaying a persistent
-icon in the status bar, to vibrating, playing sounds, or flashing lights to
-get the user's attention. In all cases, the user must explicitly shift their
-focus to the notification before they can interact with it.</p>
-
-<p>The following code demonstrates using NotificationManager to display a basic text
- popup when a new SMS message arrives in a listening service, and provides the
- current message count. You can see several more examples in the ApiDemos application,
- under app/ (named <em>notification</em>*.java).</p>
-<pre>static void setNewMessageIndicator(Context context, int messageCount){
- // Get the static global NotificationManager object.
- NotificationManager nm = NotificationManager.getDefault();</p>
-
- // If we're being called because a new message has been received,
- // then display an icon and a count. Otherwise, delete the persistent
- // message.
- if (messageCount > 0) {
- nm.notifyWithText(myApp.NOTIFICATION_GUID, // ID for this notification.
- messageCount + " new message" + messageCount > 1 ? "s":"", // Text to display.
- NotificationManager.LENGTH_SHORT); // Show it for a short time only.
- }
-}</pre>
-<p>To display a notification in the status bar and have it launch an intent when
- the user selects it (such as the new text message notification does), call {@link
- android.app.NotificationManager#notify(int, android.app.Notification) NotificationManager.notify()},
- and pass in vibration patterns, status bar icons, or Intents to associate with
- the notification. </p>
-<a name="progressbar" id="progressbar"></a><h2>Displaying a Progress Bar</h2>
-<p>An activity can display a progress bar to notify the user that something is happening.
- To display a progress bar in a screen, call {@link android.app.Activity#requestWindowFeature(int)
- Activity.requestWindowFeature(Window.FEATURE_PROGRESS)}. To set the value
- of the progress bar, call {@link android.view.Window#setFeatureInt(int,int)
- Activity.getWindow().setFeatureInt(Window.FEATURE_PROGRESS, <em>level</em>)}.
- Progress bar values are from 0 to 9,999, or set the value to 10,000 to make the
- progress bar invisible. </p>
-<p>You can also use the {@link android.app.ProgressDialog ProgressDialog} class,
- which enables a dialog box with an embedded progress bar to send a "I'm working
- on it" notification to the user. </p>
-<a name="addmenuitems" id="addmenuitems"></a><h2>Adding Items to the Screen Menu</h2>
-<p>See <a href="{@docRoot}guide/topics/ui/menus.html">Creating Menus</a>.</p>
-
-<a name="webpage" id="webpage"></a><h2>Display a Web Page</h2>
-<p>Use the {@link android.webkit.WebView webkit.WebView} object. </p>
-<a name="binding" id="binding"></a><h2>Binding to Data</h2>
-<p>You can bind a ListView to a set of underlying data by using a shim class called
- {@link android.widget.ListAdapter ListAdapter} (or a subclass). ListAdapter subclasses
- bind to a variety of data sources, and expose a common set of methods such as
- getItem() and getView(), and uses them to pick View items to display in its list.
- You can extend ListAdapter and override getView() to create your own custom list
- items. There are essentially only two steps you need to perform to bind to data: </p>
-<ol>
- <li>Create a ListAdapter object and specify its data source</li>
- <li>Give the ListAdapter to your ListView object.</li>
-</ol>
-<p>That's it!</p>
-<p>Here's an example of binding a ListActivity screen to the results from a cursor
- query. (Note that the setListAdapter() method shown is a convenience method that
- gets the page's ListView object and calls setAdapter() on it.)</p>
-<pre>// Run a query and get a Cursor pointing to the results.
-Cursor c = People.query(this.getContentResolver(), null);
-startManagingCursor(c);
-
-// Create the ListAdapter. A SimpleCursorAdapter lets you specify two interesting things:
-// an XML template for your list item, and
-// The column to map to a specific item, by ID, in your template.
-ListAdapter adapter = new SimpleCursorAdapter(this,
- android.R.layout.simple_list_item_1, // Use a template that displays a text view
- c, // Give the cursor to the list adapter
- new String[] {People.NAME} , // Map the NAME column in the people database to...
- new String[] {"text1"}); // The "text1" view defined in the XML template
-setListAdapter(adapter);</pre>
-<p>See view/List4 in the ApiDemos project for an example of extending ListAdapter
- for a new data type. </p>
-
-<a name="handle"></a>
-
-<h2>Getting a Handle to a Screen Element</h2>
-<p>You can get a handle to a screen element by calling {@link
-android.app.Activity#findViewById(int) Activity.findViewById}. You can then use
-the handle to set or retrieve any values exposed by the object. </p>
-<a name="captureimages" id="captureimages"></a><h2>Capture Images from the Phone Camera</h2>
-<p>You can hook into the device's camera onto your own Canvas object by using the
- {@link android.hardware.Camera Camera} class. See that class's documentation,
- and the ApiDemos project's Camera Preview application (Graphics/Camera Preview)
- for example code. </p>
-
-
-<a name="threading" id="threading"></a><h2>Handling Expensive Operations in the UI Thread</h2>
-<p>Avoid performing long-running operations (such as network I/O) directly in the UI thread —
-the main thread of an application where the UI is run — or your application may be blocked
-and become unresponsive. Here is a brief summary of the recommended approach for handling expensive operations:</p>
-<ol>
-<li>Create a Handler object in your UI thread</li>
-<li>Spawn off worker threads to perform any required expensive operations</li>
-<li>Post results from a worker thread back to the UI thread's handler either through a Runnable or a {@link android.os.Message}</li>
-<li>Update the views on the UI thread as needed</li>
-</ol>
-
-<p>The following outline illustrates a typical implementation:</p>
-
-<pre>
-public class MyActivity extends Activity {
-
- [ . . . ]
- // Need handler for callbacks to the UI thread
- final Handler mHandler = new Handler();
-
- // Create runnable for posting
- final Runnable mUpdateResults = new Runnable() {
- public void run() {
- updateResultsInUi();
- }
- };
-
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
-
- [ . . . ]
- }
-
- protected void startLongRunningOperation() {
-
- // Fire off a thread to do some work that we shouldn't do directly in the UI thread
- Thread t = new Thread() {
- public void run() {
- mResults = doSomethingExpensive();
- mHandler.post(mUpdateResults);
- }
- };
- t.start();
- }
-
- private void updateResultsInUi() {
-
- // Back in the UI thread -- update our UI elements based on the data in mResults
- [ . . . ]
- }
-}
-</pre>
-
-<p>For further discussions on this topic, see
-<a href="{@docRoot}guide/practices/design/responsiveness.html">Designing for Responsiveness</a>
-and the {@link android.os.Handler} documentation.</p>
-
-<a name="selectingtext" id="selectingtext"></a><h2>Selecting, Highlighting, or Styling Portions of Text</h2>
-<p>You can highlight or style the formatting of strings or substrings of text in
- a TextView object. There are two ways to do this:</p>
-<ul>
- <li>If you use a <a href="{@docRoot}guide/topics/resources/available-resources.html#stringresources">string resource</a>,
- you can add some simple styling, such as bold or italic using HTML notation.
- The currently supported tags are: <code>B</code> (bold),
- <code>I</code> (italic), <code>U</code> (underline),
- <code>TT</code> (monospace), <code>BIG</code>, <code>SMALL</code>,
- <code>SUP</code> (superscript), <code>SUB</code> (subscript),
- and <code>STRIKE</code> (strikethrough).
- So, for example, in res/values/strings.xml you could declare this:<br />
- <code><resource><br />
- <string id="@+id/styled_welcome_message">We
- are <b><i>so</i></b> glad to see you.</string><br />
- </resources></code></li>
- <li>To style text on the fly, or to add highlighting or more complex styling,
- you must use the Spannable object as described next. </li>
-</ul>
-<p>To style text on the fly, you must make sure the TextView is using {@link android.text.Spannable}
- storage for the text (this will always be true if the TextView is an EditText),
- retrieve its text with {@link android.widget.TextView#getText}, and call {@link
- android.text.Spannable#setSpan}, passing in a new style class from the {@link
- android.text.style} package and the selection range. </p>
-<p>The following code snippet demonstrates creating a string with a highlighted section,
- italic section, and bold section, and adding it to an EditText object. </p>
-<pre>// Get our EditText object.
-EditText vw = (EditText)findViewById(R.id.text);
-
-// Set the EditText's text.
-vw.setText("Italic, highlighted, bold.");
-
-// If this were just a TextView, we could do:
-// vw.setText("Italic, highlighted, bold.", TextView.BufferType.SPANNABLE);
-// to force it to use Spannable storage so styles can be attached.
-// Or we could specify that in the XML.
-
-// Get the EditText's internal text storage
-Spannable str = vw.getText();
-
-// Create our span sections, and assign a format to each.
-str.setSpan(new StyleSpan(android.graphics.Typeface.ITALIC), 0, 7, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-str.setSpan(new BackgroundColorSpan(0xFFFFFF00), 8, 19, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-str.setSpan(new StyleSpan(android.graphics.Typeface.BOLD), 21, str.length() - 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-</pre>
-
-<a name="querymap" id="querymap"></a><h2>Utilizing attributes in a Map query</h2>
-<p>
-When using a search intent to ask the Maps activity to search for something, the Maps activity responds to the following attributes in the optional context bundle:
-</p>
-<pre>
- float "centerLatitude" default 0.0f
- float "centerLongitude" default 0.0f
- float "latitudeSpan" default 0.0f
- float "longitudeSpan" default 0.0f
- int "zoomLevel" default 10
-</pre>
-<p>
-This context information is used to center the search result in a particular area, and is equivalent to adjusting the Map activity to the described location and zoom level before issuing the query.
-</p>
-<p>
-If the latitudeSpan, longitudeSpan, and zoomLevel attributes are not consistent, then it is undefined which one takes precedence.
-</p>
-
-<a name="filelist" id="filelist"></a><h2>List of Files for an Android Application</h2>
-<p>The following list describes the structure and files of an Android application.
- Many of these files can be built for you (or stubbed out) by the android tool
- shipped in the tools/ menu of the SDK. </p>
-<table width="100%" border="0">
- <tr>
- <td width="28%" valign="top">MyApp/<br /></td>
- <td width="72%" valign="top"> </td>
- </tr>
- <tr>
- <td valign="top"> AndroidManifest.xml</td>
- <td valign="top">(<em>required</em>) Advertises the screens that this application provides,
- where they can be launched (from the main program menu or elsewhere),
- any content providers it implements and what kind of data they handle,
- where the implementation classes are, and other application-wide
- information. Syntax details for this file are described in <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">The AndroidManifest.xml File</a>.</td>
- </tr>
- <tr>
- <td valign="top"> src/<br />
- /<em>myPackagePath</em>/.../<em>MyClass</em>.java</td>
- <td valign="top">(<em>required</em>) This folder holds all the source code files for your
- application, inside the appropriate package subfolders. </td>
- </tr>
- <tr>
- <td valign="top"> res/</td>
- <td valign="top">(<em>required</em>) This folder holds all the <em>resources</em> for
- your application. Resources are external data files or description files
- that are compiled into your code at build time. Files in different folders
- are compiled differently, so you must put the proper resource into the
- proper folder. (See <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources</a> for details.)</td>
- </tr>
- <tr>
- <td valign="top"> anim/<br />
- <em>animation1</em>.xml<br />
- <em>...</em></td>
- <td valign="top">(<em>optional</em>) Holds any animation XML description files that the
- application uses. The format of these files is described in <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources</a>. </td>
- </tr>
- <tr>
- <td valign="top"> drawable/<br />
- <em>some_picture</em>.png<br />
- <em>some_stretchable</em>.9.png<br />
- <em>some_background</em>.xml<br />
- ...</td>
- <td valign="top">(<em>optional</em>) Zero or more files that will be compiled to {@link
- android.graphics.drawable android.graphics.drawable} resources. Files
- can be image files (png, gif, or other) or XML files describing other
- graphics such as bitmaps, stretchable bitmaps, or gradients. Supported
- bitmap file formats are PNG (preferred), JPG, and GIF (discouraged),
- as well as the custom 9-patch stretchable bitmap format. These formats
- are described in <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources</a>. </td>
- </tr>
- <tr>
- <td valign="top"> layout/<br />
- <em>screen_1_layout</em>.xml<br />
- ...<br /></td>
- <td valign="top">(<em>optional</em>) Holds all the XML files describing screens or parts
- of screens. Although you could create a screen in Java, defining them
- in XML files is typically easier. A layout file is similar in concept
- to an HTML file that describes the screen layout and components. See <a href="{@docRoot}guide/topics/ui/index.html">User Interface</a> for more information about designing screens, and <a href="{@docRoot}guide/topics/resources/available-resources.html#layoutresources">Available Resource Types</a> for the syntax of these files.</td>
- </tr>
- <tr>
- <td valign="top"> values/<br />
- arrays<br />
- classes.xml<br />
- colors.xml<br />
- dimens.xml<br />
- strings.xml<br />
- styles.xml<br />
- values.xml<br /></td>
- <td valign="top"><p>(<em>optional</em>) XML files describing additional resources
- such as strings, colors, and styles. The naming, quantity, and number
- of these files are not enforced--any XML file is compiled, but these
- are the standard names given to these files. However, the syntax
- of these files is prescribed by Android, and described in <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources</a>. </p>
- </td>
- </tr>
- <tr>
- <td valign="top"> xml/</td>
- <td valign="top">(<em>optional</em>) XML files that can be read at run time on the device. </td>
- </tr>
- <tr>
- <td valign="top"> raw/</td>
- <td valign="top">(<em>optional</em>) Any files to be copied directly to the device. </td>
- </tr>
-</table>
-
-
-<a name="logging" ></a>
-<h2>Print Messages to a Log File</h2>
-
-<p>To write log messages from your application:</p>
-<ol><li>Import <code>android.util.Log</code>.</li>
- <li>Use <code>Log.v()</code>, <code>Log.d()</code>, <code>Log.i()</code>,
- <code>Log.w()</code>, or <code>Log.e()</code> to log messages.
- (See the {@link android.util.Log} class.)<br/> E.g.,
- <code>Log.e(this.toString(), "error: " + err.toString())</code></li>
- <li>Launch <a href="{@docRoot}guide/developing/tools/ddms.html">DDMS</a> from a terminal
- by executing <code>ddms</code> in your Android SDK <code>/tools</code> path.</li>
- <li>Run your application in the Android emulator.</li>
- <li>From the DDMS application, select the emulator
- (e.g., "emulator-5554") and click <b>Device > Run logcat...</b>
- to view all the log data.</li>
-</ol>
-<p class="note"><strong>Note:</strong> If you are running Eclipse and
-encounter a warning about the VM debug port when opening DDMS, you can ignore it
-if you're only interested in logs. However, if you want to further inspect and
-control your processes from DDMS, then you should close Eclipse before launching DDMS so that
-it may use the VM debugging port.</p>
-
+<script type="text/javascript">
+ document.location=toRoot+"resources/faq/commontasks.html"
+</script>
+<p>You should have already been redirected by your browser. Please follow
+<a href="{@docRoot}resources/faq/commontasks.html">this link</a>.</p>
\ No newline at end of file
-page.title=Troubleshooting
-parent.title=FAQs, Tips, and How-to
-parent.link=index.html
@jd:body
+<script type="text/javascript">
+ document.location=toRoot+"resources/faq/troubleshooting.html"
+</script>
-<p>Here are some tips and tricks for common Android errors. Don't forget to use the
- ddms logcat capability to get a deeper view when errors occur. See <a href="{@docRoot}guide/developing/debug-tasks.html">Debugging</a> for more debugging tips. </p>
-<ul>
- <li><a href="#installeclipsecomponents">ADT Installation Error: "requires plug-in org.eclipse.wst.sse.ui".</a></li>
- <li><a href="#nodevice">ADB reports "no device" when an emulator is running</a></li>
- <li><a href="#noapp">My new application/activity isn't showing up in the device application
- list </a></li>
- <li><a href="#noupdate">I updated my app, but the updates don't seem to be showing up on
- the device</a></li>
- <li><a href="#layout_wilih">I'm getting a "Binary XML file line #2: You must supply a layout_wilih
- attribute" error when I start an application</a></li>
- <li><a href="#permission">My request to (<em>make a call, catch an incoming SMS, receive
- a notification, send an intent to an Android application</em>) is being
- ignored</a></li>
- <li><a href="#build">Help! My project won't build in Eclipse</a></li>
- <li><a href="#eclipse">Eclipse isn't talking to the emulator</a></li>
- <li><a href="#majorminor">When I go to preferences in Eclipse and select "Android", I get the following error message: Unsupported major.minor version 49.0.</a></li>
- <li><a href="#apidemosreinstall">I can't install ApiDemos apps in my IDE because of a signing error</a></li>
- <li><a href="#gesturebuilderinstall">I can't install the GestureBuilder sample
-app in the emulator</a></li>
- <li><a href="#signingcalendar">I can't compile my app because the build tools generated an expired debug certificate</a></li>
- <li><a href="#manifestfiles">Unable to view manifest files from within Eclipse</a></li>
-</ul>
-
-<a name="installeclipsecomponents" id="installeclipsecomponents"></a><h2>ADT Installation Error: "requires plug-in org.eclipse.wst.sse.ui".</h2>
-<p>
-The "Android Editors" feature of the ADT Plugin requires specific Eclipse components, such as WST. If you
-encounter this error message during ADT installation, you need to install the
-required Eclipse components and then try the ADT installation again. Follow the steps below to install the required components for the
-Android Editors feature, based on the version of Eclipse that you are using.</p>
-
-<table style="font-size:100%">
-<tr><th>Eclipse 3.3 (Europa)</th><th>Eclipse 3.4 (Ganymede)</th></tr>
-<tr>
-<td width="50%">
-<ol>
-<li>From the dialog where you select the <strong>Update sites to visit</strong>, select the checkboxes for both the
-ADT site, and the Callisto/Europa/Ganymede Discovery Site (you may want to
-check <strong>Automatically select mirrors</strong> at the bottom).</li>
-<li>Click <strong>Finish</strong>.</li>
-<li>In the <strong>Next</strong> dialog, select the Android Plugins.</li>
-<li>Now, expand the tree item of the discovery site. It seems that if you
-don't do it, it doesn't load the content of the discovery site.</li>
-<li>On the right, click <strong>Select required</strong>. This will select all the components
-that are required to install the Android plugin (wst, emf, etc...).</li>
-<li>Click <strong>Next</strong>, accept the agreement, click <strong>Install All</strong>, and restart Eclipse.</li>
-</ol>
-</td>
-<td>
-<ol>
- <li>Select <strong>Help</strong> > <strong>Software Updates...</strong></li>
- <li>Select the <strong>Installed Software</strong> tab.</li>
- <li>Click <strong>Update...</strong></li>
- <li>If an update for ADT is available, select it and click <strong>Finish</strong>.</li>
-</ol>
-</td>
-</tr>
-</table>
-
-
-</p>
-<a name="nodevice"></a><h2>ADB reports "no device" when an emulator is running</h2>
- <p>Try restarting adb by stopping it (<code>adb
- kill-server</code>) then any other adb command to restart it.</p>
-
-<a name="noapp"></a><h2>My new application/activity isn't showing up in the
- applications list </h2>
-<ul>
- <li>You often must restart your device or emulator before a new activity shows
- up in the applications list. This is particularly true when it is a completely
- new application with a new AndroidManifest.xml file.</li>
- <li>If this is for a new activity in an existing AndroidManifest.xml file, did
- you include an <code><activity></code> tag for your app (or a <code><service></code> tag
- for a service, or a <code><receiver></code> tag for a receiver, etc.)? </li>
- <li>Make sure that your AndroidManifest.xml file is valid. Errors in attribute
- values, such as the <em>value </em> attribute in <code><action <em>value</em>="<em><something></em>"></code>
- will often not be caught by compilers, but will prevent your application
- from being displayed because the intent filter will not be matched. Extra
- spaces or other characters can often sneak into these strings.</li>
- <li>Did you send your .apk file to the device (<a href="{@docRoot}guide/developing/tools/adb.html#move">adb install</a>)?</li>
- <li>Run logcat on your device (<code>adb logcat</code>)
- and then install your .apk file. Check the logcat output to see whether the
- application is being installed and recognized properly. Here's sample output
- from a successful installation:
-<pre>I/FileObserver( 414): *** onEvent wfd: 3 mask: 8 path: MyRSSReader.apk
-D/PackageManager( 414): Scanning package: /data/app/MyRSSReader.apk
-D/PackageManager( 414): Adding package com.example.codelab.rssexample
-D/PackageManager( 414): Registered content provider: my_rss_item, className = com.example.codelab.rssexample.RssContentProvider, isSyncable = false
-D/PackageManager( 414): Providers: com.example.codelab.rssexample.RssContentProvider
-D/PackageManager( 414): Activities: com.example.codelab.rssexample.MyRssReader com.example.codelab.rssexample.MyRssReader2 </pre>
- </li>
- <li>If logcat shows that the package manager is having problems loading the manifest
- file, force your manifest to be recompiled by adding a space in the file and
- compiling it.</li>
-</ul>
-<a name="noupdate"></a><h2>I updated my app, but the updates don't seem to be showing up on the device</h2>
- <p>Did you remember to send your .apk file to the device (<a href="{@docRoot}guide/developing/tools/adb.html#move">adb
- install</a>)?</p>
-
-<a name="layout_wilih"></a><h2>I'm getting a "Binary XML file line #2: You must supply a layout_wilih
- attribute" error
- when I start an application (but I declare a layout_wilih attribute <em>right
- there!!!</em>)</h2>
-<ul>
- <li>Make sure that the SDK you are building with is the same version as the Android
- OS that you are running on. </li>
- <li>Make sure that you're calling setContentView() early in your onCreate() method.
- Calling other methods, such as setListAdapter() before calling setContentView()
- can sometimes create odd errors when Android tries to access screen elements
- that haven't been set before.</li>
-</ul>
-<a name="permission"></a><h2>My request to (<em>make a call, catch an incoming SMS,
-receive a notification, send an intent to an Android application</em>) is being
-ignored</h2>
- <p>You might not have permission (or might not have requested permission) to
- call this activity or receive this intent. Many standard Android activities,
- such as making a call, have a permission assigned to it to prevent arbitrary
- applications from sending or receiving requests. See <a
- href="{@docRoot}guide/topics/security/security.html">Security and
- Permissions</a> for more information on permissions, and
- {@link android.Manifest.permission Manifest.permission} for a list of
- standard permissions supported by the Android platform.
-</p>
-<a name="build"></a><h2>Help! My project won't build in Eclipse</h2>
-<p>If your project doesn't build, you may notice symptoms such as new
-resources added in the <code>res/</code> sub-folders not showing up in the R class,
-the emulator not being started, not being able to run the application, or even seeming to run an old version of the application.</p>
-<p>To troubleshoot these types of problems, first try:</p>
-<ol>
- <li>Switch to the DDMS view in Eclipse (if you don't already have it open):
- <ol type="a">
- <li>From the menu select <code>Window > Open Perspective > Other</code></li>
- <li>Select DDMS from the list and hit OK</li>
- </ol>
- </li>
- <li>In the Devices panel (top right panel by default), click on the down triangle
- to bring up the panel menu</li>
- <li>Select <code>Reset ADB</code> from the menu, and then try running the
- application again</li>
-</ol>
-<p>If the above still doesn't work, you can try these steps:</p>
-<ol>
- <li>
- Check the console and problems tabs at the bottom of the Eclipse UI
- </li>
- <li>
- If there are problems listed in either place, they should give you a clue
- what is wrong
- </li>
- <li>
- If you aren't sure if the problems are fresh or stale, clear the console
- with a right click > Clear, then clean the project
- </li>
- <li>
- To clean the project (a good idea with any kind of build error), select
- Project > Clean from the eclipse main menu, then select the project you
- are working on (or clean all)
- </li>
-</ol>
-<a name="eclipse"></a><h2>Eclipse isn't talking to the emulator</h2>
-<p>When communication doesn't seem to be happening between Eclipse and the emulator, symptoms can include: nothing happening when you press run, the emulator hanging waiting
-for a debugger to connect, or errors that Eclipse reports about not being able
-to find the emulator or shell. By far the most common symptom is that when you press run, the emulator starts (or
-is already running), but the application doesn't start.</p>
-<p>
-You may find any of these steps will fix the problem and with practice you
-probably can figure out which one you need to do for your particular issue, but
-to start with, the safest option is to run through all of them in order:</p>
-<ol>
- <li>
- Quit the emulator if it is running
- </li>
- <li>
- Check that any emulator processes are killed (sometimes they can hang, use ps on unix or mac, or task manager in the process view on
- windows).
- </li>
- <li>
- Quit Eclipse
- </li>
- <li>
- From the command line, type:
-<pre>adb kill-server </pre>
- </li>
- <li>
- Start Eclipse and try again
- </li>
-</ol>
-
-<a name="majorminor"></a><h2>When I go to preferences in Eclipse and select "Android", I get the following error message: Unsupported major.minor version 49.0.</h2>
-<p>This error is displayed if you are using an older version of the JDK. Please make sure you are using JDK version 5 or 6.</p>
-
-<h2 id="apidemosreinstall">I can't install ApiDemos apps in my IDE because of a signing error</a></h2>
-
-<p>The Android system requires that all applications be signed, as described in
- <a href="{@docRoot}guide/publishing/app-signing.html">Signing Your Applications</a>. The ApiDemos
-applications included with the SDK are preinstalled on the emulator and for that reason have been
-compiled and signed with a private key.</p>
-
-If you want to modify or run one of the ApiDemos apps from Eclipse/ADT or other IDE, you can do so
-so only after you uninstall the <em>preinstalled</em> version of the app from the emulator. If
-you try to run an ApiDemos app from your IDE without removing the preinstalled version first,
-you will get errors similar to these: </p>
-
-<pre>[2008-08-13 15:14:15 - ApiDemos] Re-installation failed due to different application signatures.
-[2008-08-13 15:14:15 - ApiDemos] You must perform a full uninstall of the application. WARNING: ...This will remove the application data!
-[2008-08-13 15:14:15 - ApiDemos] Please execute 'adb uninstall com.android.samples' in a shell.</pre>
-
-<p>The error occurs because, in this case, you are attempting to install another copy of ApiDemos
-onto the emulator, a copy that is signed with a different certificate. (The Android IDE tools will
-have signed the app with a debug certificate, where the existing version was already signed with
-a private certificate.) The system does not allow this type of reinstallation. </p>
-
-<p>To resolve the issue, you need to fully uninstall the preinstalled and then reinstall it using
-the adb tool. Here's how to do that:</p>
-
-<ol>
- <li>In a terminal, change to the tools directory of the SDK.</li>
- <li>If no emulator instance is running, start an emulator using using the command <code>emulator &</code>.</li>
- <li>Uninstall the preinstalled app using the command <code>adb uninstall com.android.samples</code>.</li>
- <li>Reinstall the app using the command <code>adb install <path to the ApiDemos.apk></code>. If you are
- working in Eclipse/ADT, you can just compile and run the app in the normal way. </li>
-</ol>
-
-<p>Note that if multiple emulator instances are running, you need to direct your uninstall/install
-commands to the emulator instance that you are targeting. To do that you can add the
-<code>-s <serialNumber></code> to the command, for example: </p>
-
-<pre>adb -s emulator-5556 install</pre>
-
-<p>For more information about adb, see the <a href="{@docRoot}guide/developing/tools/adb.html">Android Debug Bridge</a>
-documentation.</p>
-
-<h2 id="gesturebuilderinstall">I can't install the GestureBuilder sample
-app in the emulator</a></h2>
-
-<p>This is similar to the ApiDemos problem described above, except that
-you cannot fix it by uninstalling GestureBuilder from the emulator. The
-GestureBuilder app cannot be uninstalled because it is currently installed
-within the system files themselves.</p>
-
-<p><strong>Symptoms</strong></p>
-
-<ul><li><p>You cannot run GestureBuilder in the emulator:</p>
-
-<pre>[2009-12-10 14:57:19 - GestureBuilderActivity]Re-installation failed due to different application signatures.
-[2009-12-10 14:57:19 - GestureBuilderActivity]You must perform a full uninstall of the application. WARNING: This will remove the application data!
-[2009-12-10 14:57:19 - GestureBuilderActivity]Please execute 'adb uninstall com.android.gesture.builder' in a shell.</pre>
-</li>
-
-<li><p>Running <code>adb uninstall com.android.gesture.builder</code> fails:</p>
-<pre>$ adb uninstall com.android.gesture.builder
- Failure</pre>
-</li></ul>
-
-<p>For now, the work-around is to change the sample's package name
-so that the system can install it as a new app rather than as a
-replacement for the existing GestureBuilder app. To change the
-package name, open the manifest file and modify the package attribute
-of the manifest element. Next, update imports and other references to
-the package name, rebuild the app, and run it in an AVD.</p>
-
-<p>For example, here's how you could do this in Eclipse:</p>
-
-<ol>
- <li>Right-click on the package name
-(<code>src/com.android.gesture.builder</code>).</li>
- <li>Select <strong>Refactor > Rename</strong> and change the name, for example to
-<code>com.android.gestureNEW.builder</code>. </li>
- <li>Open the manifest file. Inside the <code><manifest></code>
-tag, change the package name to
-<code>com.android.gestureNEW.builder</code>.</li>
- <li>Open each of the two Activity files and do Ctrl-Shift-O to add
-missing import packages, then save each file.</li>
-<li>Run the GestureBuilder application on the emulator.</li>
-</ol>
-
-<p>If you get an error message such as "Could not load /sdcard/gestures.
-Make sure you have a mounted SD card," be sure that your target AVD has an
-SD card. To create an AVD that has an SD card, use the
-<a href="{@docRoot}guide/developing/tools/avd.html#options"><code>-c</code>
-option</a> in the <code>android create avd</code> command.</p>
-
-<h2 id="signingcalendar">I can't compile my app because the build tools generated an expired debug certificate</h2>
-
-<p>If your development machine uses a locale that has a non-Gregorian calendar, you may encounter problems when first trying to compile and run your application. Specifically, you may find that the Android build tools won't compile your application because the debug key is expired. </p>
-
-<p>The problem occurs because the Keytool utility — included in the JDK and used by the Android build tools — fails to properly handle non-Gregorian locales and may create validity dates that are in the past. That is, it may generate a debug key that is already expired, which results in the compile error.</p>
-
-<p>If you encounter this problem, follow these steps to work around it: </p>
-
-<ol>
-<li>First, delete the debug keystore/key already generated by the Android build tools. Specifically, delete the <code>debug.keystore</code> file. On Linux/Mac OSX, the file is stored in <code>~/.android</code>. On Windows XP, the file is stored in <code>
-C:\Documents and Settings\<user>\.android</code>. On Windows Vista, the file is stored in <code>
-C:\Users\<user>\.android</code></li>
-<li>Next, you can either
-<ul>
-<li>Temporarily change your development machine's locale (date and time) to one that uses a Gregorian calendar, for example, United States. Once the locale is changed, use the Android build tools to compile and install your app. The build tools will regenerate a new keystore and debug key with valid dates. Once the new debug key is generated, you can reset your development machine to the original locale. </li>
-<li>Alternatively, if you do not want to change your machine's locale settings, you can generate the keystore/key on any machine using the Gregorian calendar, then copy the <code>debug.keystore</code> file from that computer to the proper location on your development machine. </li>
-</ul>
-</li>
-</ol>
-
-<p>This problem has been verified on Windows and may apply to other platforms. </p>
-
-<p>For general information about signing Android applications, see
-<a href="{@docRoot}guide/publishing/app-signing.html">Signing Your Applications</a>. </p>
-
-<h2 id="manifestfiles">Unable to view manifest files from within
-Eclipse</a></h2>
-
-<p>When you try to open an application's manifest file from within
-Eclipse, you might get an error such as this one:</p>
-<pre>An error has occurred. See error log for more details.
-org.eclipse.wst.sse.ui.StructuredTextEditor.isBlockSelectionModeEnabled()Z</pre>
-
-<p>Try reverting to the 3.0 version of the Eclipse XML Editors and
-Tools. If this does not work, remove the 3.1 version of the tool. To do
-this in Eclipse 3.4:</p>
-
-<ol>
- <li>Select <strong>Help > Software Updates...</strong></li>
- <li>Select the <strong>Installed Software</strong> tab.</li>
- <li>Select <strong>Eclipse XML Editors and Tools</strong>.</li>
- <li>Click <strong>Uninstall</strong>.</li>
- <li>Click <strong>Finish</strong>.</li>
-</ol>
-
-<p>When you restart Eclipse, you should be able to view the manifest
-files. </p>
+<p>You should have already been redirected by your browser. Please follow
+<a href="{@docRoot}resources/faq/troubleshooting.html">this link</a>.</p>
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