import android.content.Context;
import android.content.res.Resources;
+import android.os.Build;
+import android.os.Handler;
import android.os.SystemClock;
import android.util.FloatMath;
private float mFocusX;
private float mFocusY;
+ private boolean mDoubleTapScales;
+
private float mCurrSpan;
private float mPrevSpan;
private float mInitialSpan;
private int mTouchHistoryDirection;
private long mTouchHistoryLastAcceptedTime;
private int mTouchMinMajor;
+ private MotionEvent mDoubleTapEvent;
+ private int mDoubleTapMode = DOUBLE_TAP_MODE_NONE;
+ private final Handler mHandler;
private static final long TOUCH_STABILIZE_TIME = 128; // ms
- private static final int TOUCH_MIN_MAJOR = 48; // dp
+ private static final int DOUBLE_TAP_MODE_NONE = 0;
+ private static final int DOUBLE_TAP_MODE_IN_PROGRESS = 1;
+
/**
* Consistency verifier for debugging purposes.
private final InputEventConsistencyVerifier mInputEventConsistencyVerifier =
InputEventConsistencyVerifier.isInstrumentationEnabled() ?
new InputEventConsistencyVerifier(this, 0) : null;
+ private GestureDetector mGestureDetector;
+
+ private boolean mEventBeforeOrAboveStartingGestureEvent;
+ /**
+ * Creates a ScaleGestureDetector with the supplied listener.
+ * You may only use this constructor from a {@link android.os.Looper Looper} thread.
+ *
+ * @param context the application's context
+ * @param listener the listener invoked for all the callbacks, this must
+ * not be null.
+ *
+ * @throws NullPointerException if {@code listener} is null.
+ */
public ScaleGestureDetector(Context context, OnScaleGestureListener listener) {
+ this(context, listener, null);
+ }
+
+ /**
+ * Creates a ScaleGestureDetector with the supplied listener.
+ * @see android.os.Handler#Handler()
+ *
+ * @param context the application's context
+ * @param listener the listener invoked for all the callbacks, this must
+ * not be null.
+ * @param handler the handler to use for running deferred listener events.
+ *
+ * @throws NullPointerException if {@code listener} is null.
+ */
+ public ScaleGestureDetector(Context context, OnScaleGestureListener listener,
+ Handler handler) {
mContext = context;
mListener = listener;
mSpanSlop = ViewConfiguration.get(context).getScaledTouchSlop() * 2;
final Resources res = context.getResources();
mTouchMinMajor = res.getDimensionPixelSize(
com.android.internal.R.dimen.config_minScalingTouchMajor);
- mMinSpan = res.getDimensionPixelSize(
- com.android.internal.R.dimen.config_minScalingSpan);
+ mMinSpan = res.getDimensionPixelSize(com.android.internal.R.dimen.config_minScalingSpan);
+ mHandler = handler;
+ // Quick scale is enabled by default after JB_MR2
+ if (context.getApplicationInfo().targetSdkVersion > Build.VERSION_CODES.JELLY_BEAN_MR2) {
+ setQuickScaleEnabled(true);
+ }
}
/**
final int action = event.getActionMasked();
+ // Forward the event to check for double tap gesture
+ if (mDoubleTapScales) {
+ mGestureDetector.onTouchEvent(event);
+ }
+
final boolean streamComplete = action == MotionEvent.ACTION_UP ||
action == MotionEvent.ACTION_CANCEL;
+
if (action == MotionEvent.ACTION_DOWN || streamComplete) {
// Reset any scale in progress with the listener.
// If it's an ACTION_DOWN we're beginning a new event stream.
mListener.onScaleEnd(this);
mInProgress = false;
mInitialSpan = 0;
+ mDoubleTapMode = DOUBLE_TAP_MODE_NONE;
}
if (streamComplete) {
final boolean configChanged = action == MotionEvent.ACTION_DOWN ||
action == MotionEvent.ACTION_POINTER_UP ||
action == MotionEvent.ACTION_POINTER_DOWN;
+
+
final boolean pointerUp = action == MotionEvent.ACTION_POINTER_UP;
final int skipIndex = pointerUp ? event.getActionIndex() : -1;
// Determine focal point
float sumX = 0, sumY = 0;
final int count = event.getPointerCount();
- for (int i = 0; i < count; i++) {
- if (skipIndex == i) continue;
- sumX += event.getX(i);
- sumY += event.getY(i);
- }
final int div = pointerUp ? count - 1 : count;
- final float focusX = sumX / div;
- final float focusY = sumY / div;
+ final float focusX;
+ final float focusY;
+ if (mDoubleTapMode == DOUBLE_TAP_MODE_IN_PROGRESS) {
+ // In double tap mode, the focal pt is always where the double tap
+ // gesture started
+ focusX = mDoubleTapEvent.getX();
+ focusY = mDoubleTapEvent.getY();
+ if (event.getY() < focusY) {
+ mEventBeforeOrAboveStartingGestureEvent = true;
+ } else {
+ mEventBeforeOrAboveStartingGestureEvent = false;
+ }
+ } else {
+ for (int i = 0; i < count; i++) {
+ if (skipIndex == i) continue;
+ sumX += event.getX(i);
+ sumY += event.getY(i);
+ }
+ focusX = sumX / div;
+ focusY = sumY / div;
+ }
addTouchHistory(event);
// the focal point.
final float spanX = devX * 2;
final float spanY = devY * 2;
- final float span = FloatMath.sqrt(spanX * spanX + spanY * spanY);
+ final float span;
+ if (inDoubleTapMode()) {
+ span = spanY;
+ } else {
+ span = FloatMath.sqrt(spanX * spanX + spanY * spanY);
+ }
// Dispatch begin/end events as needed.
// If the configuration changes, notify the app to reset its current state by beginning
final boolean wasInProgress = mInProgress;
mFocusX = focusX;
mFocusY = focusY;
- if (mInProgress && (span < mMinSpan || configChanged)) {
+ if (!inDoubleTapMode() && mInProgress && (span < mMinSpan || configChanged)) {
mListener.onScaleEnd(this);
mInProgress = false;
mInitialSpan = span;
+ mDoubleTapMode = DOUBLE_TAP_MODE_NONE;
}
if (configChanged) {
mPrevSpanX = mCurrSpanX = spanX;
mCurrSpan = span;
boolean updatePrev = true;
+
if (mInProgress) {
updatePrev = mListener.onScale(this);
}
return true;
}
+
+ private boolean inDoubleTapMode() {
+ return mDoubleTapMode == DOUBLE_TAP_MODE_IN_PROGRESS;
+ }
+
+ /**
+ * Set whether the associated {@link OnScaleGestureListener} should receive onScale callbacks
+ * when the user performs a doubleTap followed by a swipe. Note that this is enabled by default
+ * if the app targets API 19 and newer.
+ * @param scales true to enable quick scaling, false to disable
+ */
+ public void setQuickScaleEnabled(boolean scales) {
+ mDoubleTapScales = scales;
+ if (mDoubleTapScales && mGestureDetector == null) {
+ GestureDetector.SimpleOnGestureListener gestureListener =
+ new GestureDetector.SimpleOnGestureListener() {
+ @Override
+ public boolean onDoubleTap(MotionEvent e) {
+ // Double tap: start watching for a swipe
+ mDoubleTapEvent = e;
+ mDoubleTapMode = DOUBLE_TAP_MODE_IN_PROGRESS;
+ return true;
+ }
+ };
+ mGestureDetector = new GestureDetector(mContext, gestureListener, mHandler);
+ }
+ }
+
/**
* Returns {@code true} if a scale gesture is in progress.
*/
* @return The current scaling factor.
*/
public float getScaleFactor() {
+ if (inDoubleTapMode() && mEventBeforeOrAboveStartingGestureEvent) {
+ // Drag is moving up; the further away from the gesture
+ // start, the smaller the span should be, the closer,
+ // the larger the span, and therefore the larger the scale
+ return (1 / mCurrSpan) / (1 / mPrevSpan);
+ }
return mPrevSpan > 0 ? mCurrSpan / mPrevSpan : 1;
}
public long getEventTime() {
return mCurrTime;
}
-}
+}
\ No newline at end of file
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