</p></dd>
<dt><a name="lmode"></a>{@code android:launchMode}</dt>
-<dd>An instruction on how the activity should be launched. There are four modes
+<dd>An instruction on how the activity should be launched. There are four modes
that work in conjunction with activity flags ({@code FLAG_ACTIVITY_*} constants)
-in {@link android.content.Intent} objects to determine what should happen when
-the activity is called upon to handle an intent. They are:
+in {@link android.content.Intent} objects to determine what should happen when
+the activity is called upon to handle an intent. They are:</p>
<p style="margin-left: 2em">"{@code standard}"
<br>"{@code singleTop}"
</p>
<p>
-The modes fall into two main groups, with "{@code standard}" and
-"{@code singleTop}" activities on one side, and "{@code singleTask}" and
-"{@code singleInstance}" activities on the other. An activity with the
-"{@code standard}" or "{@code singleTop}" launch mode can be instantiated
-multiple times. The instances can belong to any task and can be located
-anywhere in the activity stack. Typically, they're launched into the task
-that called
+As shown in the table below, the modes fall into two main groups, with
+"{@code standard}" and "{@code singleTop}" activities on one side, and
+"{@code singleTask}" and "{@code singleInstance}" activities on the other.
+An activity with the "{@code standard}" or "{@code singleTop}" launch mode
+can be instantiated multiple times. The instances can belong to any task
+and can be located anywhere in the activity stack. Typically, they're
+launched into the task that called
<code>{@link android.content.Context#startActivity startActivity()}</code>
-(unless the Intent object contains a
-<code>{@link android.content.Intent#FLAG_ACTIVITY_NEW_TASK}</code>
-instruction, in which case a different task is chosen — see the
+(unless the Intent object contains a
+<code>{@link android.content.Intent#FLAG_ACTIVITY_NEW_TASK}</code>
+instruction, in which case a different task is chosen — see the
<a href="#aff">taskAffinity</a> attribute).
</p>
<p>
-In contrast, "{@code singleTask}" and "{@code singleInstance}" activities
-can only begin a task. They are always at the root of the activity stack.
-Moreover, the device can hold only one instance of the activity at a time
+In contrast, "<code>singleTask</code>" and "<code>singleInstance</code>" activities
+can only begin a task. They are always at the root of the activity stack.
+Moreover, the device can hold only one instance of the activity at a time
— only one such task.
</p>
<p>
The "{@code standard}" and "{@code singleTop}" modes differ from each other
-in just one respect: Every time there's new intent for a "{@code standard}"
-activity, a new instance of the class is created to respond to that intent.
+in just one respect: Every time there's a new intent for a "{@code standard}"
+activity, a new instance of the class is created to respond to that intent.
Each instance handles a single intent.
-Similarly, a new instance of a "{@code singleTop}" activity may also be
-created to handle a new intent. However, if the target task already has an
-existing instance of the activity at the top of its stack, that instance
-will receive the new intent (in an
+Similarly, a new instance of a "{@code singleTop}" activity may also be
+created to handle a new intent. However, if the target task already has an
+existing instance of the activity at the top of its stack, that instance
+will receive the new intent (in an
<code>{@link android.app.Activity#onNewIntent onNewIntent()}</code> call);
a new instance is not created.
-In other circumstances — for example, if an existing instance of the
-"{@code singleTop}" activity is in the target task, but not at the top of
-the stack, or if it's at the top of a stack, but not in the target task
+In other circumstances — for example, if an existing instance of the
+"{@code singleTop}" activity is in the target task, but not at the top of
+the stack, or if it's at the top of a stack, but not in the target task
— a new instance would be created and pushed on the stack.
-</p>
+</p>
<p>
-The "{@code singleTask}" and "{@code singleInstance}" modes also differ from
-each other in only one respect: A "{@code singleTask}" activity allows other
-activities to be part of its task. It's at the root of the activity stack,
-but other activities (necessarily "{@code standard}" and "{@code singleTop}"
-activities) can be launched into the same task. A "{@code singleInstance}"
-activity, on the other hand, permits no other activities to be part of its
-task. It's the only activity in the task. If it starts another activity,
-that activity is assigned to a different task — as if {@code
+The "{@code singleTask}" and "{@code singleInstance}" modes also differ from
+each other in only one respect: A "{@code singleTask}" activity allows other
+activities to be part of its task. It's always at the root of its task, but
+other activities (necessarily "{@code standard}" and "{@code singleTop}"
+activities) can be launched into that task. A "{@code singleInstance}"
+activity, on the other hand, permits no other activities to be part of its task.
+It's the only activity in the task. If it starts another activity, that
+activity is assigned to a different task — as if {@code
FLAG_ACTIVITY_NEW_TASK} was in the intent.
</p>
+<table>
+<tr>
+<th>Use Cases</th>
+<th>Launch Mode</th>
+<th>Multiple Instances?</th>
+<th>Comments</th>
+</tr>
+<tr>
+<td rowspan="2" style="width:20%;">Normal launches for most activities</td>
+<td>"<code>standard</code>"</td>
+<td>Yes</td>
+<td>Default. The system always creates a new instance of the activity in the
+target task and routes the intent to it.</td>
+</tr>
+<tr>
+<td>"<code>singleTop</code>"</td>
+<td>Conditionally</td>
+<td>If an instance of the activity already exists at the top of the target task,
+the system routes the intent to that instance through a call to its {@link
+android.app.Activity#onNewIntent onNewIntent()} method, rather than creating a
+new instance of the activity.</td>
+</tr>
+<tr>
+<td rowspan="2">Specialized launches<br>
+<em>(not recommended for general use)</em></td>
+<td>"<code>singleTask</code>"</td>
+<td>No</td>
+<td>The system creates the activity at the root of a new task and routes the
+intent to it. However, if an instance of the activity already exists, the system
+routes the intent to existing instance through a call to its {@link
+android.app.Activity#onNewIntent onNewIntent()} method, rather than creating a
+new one.</td>
+</tr>
+<tr>
+<td>"<code>singleInstance</code>"</td>
+<td>No</td>
+<td>Same as "<code>singleTask"</code>, except that the system doesn't launch any
+other activities into the task holding the instance. The activity is always the
+single and only member of its task.</td>
+</tr>
+</table>
+
+<p>As shown in the table above, <code>standard</code> is the default mode and is
+appropriate for most types of activities. <code>SingleTop</code> is also a
+common and useful launch mode for many types of activities. The other modes
+— <code>singleTask</code> and <code>singleInstance</code> — are
+<span style="color:red">not appropriate for most applications</span>,
+since they result in an interaction model that is likely to be unfamiliar to
+users and is very different from most other applications.
+
+<p>Regardless of the launch mode that you choose, make sure to test the usability
+of the activity during launch and when navigating back to it from
+other activities and tasks using the BACK key. </p>
+
<p>For more information on launch modes and their interaction with Intent
flags, see the
<a href="{@docRoot}guide/topics/fundamentals.html#acttask">Activities and
OSDN Git Service
