Use focal point for scrolling in GestureDetector (315948f6) · Commits · e / os / android_frameworks_base

core/java/android/view/GestureDetector.java

+64 −54

Original line number	Diff line number	Diff line
		@@ -226,18 +226,13 @@ public class GestureDetector {
		*/
		private boolean mIsDoubleTapping;

		private float mLastMotionY;
		private float mLastMotionX;
		private float mLastFocusX;
		private float mLastFocusY;
		private float mDownFocusX;
		private float mDownFocusY;

		private boolean mIsLongpressEnabled;

		/**
		* True if we are at a target API level of >= Froyo or the developer can
		* explicitly set it. If true, input events with > 1 pointer will be ignored
		* so we can work side by side with multitouch gesture detectors.
		*/
		private boolean mIgnoreMultitouch;

		/**
		* Determines speed during touch scrolling
		*/
		@@ -349,8 +344,16 @@ public class GestureDetector {
		* @throws NullPointerException if {@code listener} is null.
		*/
		public GestureDetector(Context context, OnGestureListener listener, Handler handler) {
		this(context, listener, handler, context != null &&
		context.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.FROYO);
		if (handler != null) {
		mHandler = new GestureHandler(handler);
		} else {
		mHandler = new GestureHandler();
		}
		mListener = listener;
		if (listener instanceof OnDoubleTapListener) {
		setOnDoubleTapListener((OnDoubleTapListener) listener);
		}
		init(context);
		}

		/**
		@@ -362,31 +365,19 @@ public class GestureDetector {
		* @param listener the listener invoked for all the callbacks, this must
		* not be null.
		* @param handler the handler to use
		* @param ignoreMultitouch whether events involving more than one pointer should
		* be ignored.
		*
		* @throws NullPointerException if {@code listener} is null.
		*/
		public GestureDetector(Context context, OnGestureListener listener, Handler handler,
		boolean ignoreMultitouch) {
		if (handler != null) {
		mHandler = new GestureHandler(handler);
		} else {
		mHandler = new GestureHandler();
		}
		mListener = listener;
		if (listener instanceof OnDoubleTapListener) {
		setOnDoubleTapListener((OnDoubleTapListener) listener);
		}
		init(context, ignoreMultitouch);
		boolean unused) {
		this(context, listener, handler);
		}

		private void init(Context context, boolean ignoreMultitouch) {
		private void init(Context context) {
		if (mListener == null) {
		throw new NullPointerException("OnGestureListener must not be null");
		}
		mIsLongpressEnabled = true;
		mIgnoreMultitouch = ignoreMultitouch;

		// Fallback to support pre-donuts releases
		int touchSlop, doubleTapSlop, doubleTapTouchSlop;
		@@ -456,34 +447,40 @@ public class GestureDetector {
		}

		final int action = ev.getAction();
		final float y = ev.getY();
		final float x = ev.getX();

		if (mVelocityTracker == null) {
		mVelocityTracker = VelocityTracker.obtain();
		}
		mVelocityTracker.addMovement(ev);

		final boolean pointerUp = action == MotionEvent.ACTION_POINTER_UP;
		final int skipIndex = pointerUp ? ev.getActionIndex() : -1;

		// Determine focal point
		float sumX = 0, sumY = 0;
		final int count = ev.getPointerCount();
		for (int i = 0; i < count; i++) {
		if (skipIndex == i) continue;
		sumX += ev.getX(i);
		sumY += ev.getY(i);
		}
		final int div = pointerUp ? count - 1 : count;
		final float focusX = sumX / div;
		final float focusY = sumY / div;

		boolean handled = false;

		switch (action & MotionEvent.ACTION_MASK) {
		case MotionEvent.ACTION_POINTER_DOWN:
		if (mIgnoreMultitouch) {
		// Multitouch event - abort.
		cancel();
		}
		mDownFocusX = mLastFocusX = focusX;
		mDownFocusY = mLastFocusY = focusY;
		// Cancel long press and taps
		cancelTaps();
		break;

		case MotionEvent.ACTION_POINTER_UP:
		// Ending a multitouch gesture and going back to 1 finger
		if (mIgnoreMultitouch && ev.getPointerCount() == 2) {
		int index = (((action & MotionEvent.ACTION_POINTER_INDEX_MASK)
		>> MotionEvent.ACTION_POINTER_INDEX_SHIFT) == 0) ? 1 : 0;
		mLastMotionX = ev.getX(index);
		mLastMotionY = ev.getY(index);
		mVelocityTracker.recycle();
		mVelocityTracker = VelocityTracker.obtain();
		}
		mDownFocusX = mLastFocusX = focusX;
		mDownFocusY = mLastFocusY = focusY;
		break;

		case MotionEvent.ACTION_DOWN:
		@@ -504,8 +501,8 @@ public class GestureDetector {
		}
		}

		mLastMotionX = x;
		mLastMotionY = y;
		mDownFocusX = mLastFocusX = focusX;
		mDownFocusY = mLastFocusY = focusY;
		if (mCurrentDownEvent != null) {
		mCurrentDownEvent.recycle();
		}
		@@ -525,22 +522,22 @@ public class GestureDetector {
		break;

		case MotionEvent.ACTION_MOVE:
		if (mInLongPress \|\| (mIgnoreMultitouch && ev.getPointerCount() > 1)) {
		if (mInLongPress) {
		break;
		}
		final float scrollX = mLastMotionX - x;
		final float scrollY = mLastMotionY - y;
		final float scrollX = mLastFocusX - focusX;
		final float scrollY = mLastFocusY - focusY;
		if (mIsDoubleTapping) {
		// Give the move events of the double-tap
		handled \|= mDoubleTapListener.onDoubleTapEvent(ev);
		} else if (mAlwaysInTapRegion) {
		final int deltaX = (int) (x - mCurrentDownEvent.getX());
		final int deltaY = (int) (y - mCurrentDownEvent.getY());
		final int deltaX = (int) (focusX - mDownFocusX);
		final int deltaY = (int) (focusY - mDownFocusY);
		int distance = (deltaX * deltaX) + (deltaY * deltaY);
		if (distance > mTouchSlopSquare) {
		handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX, scrollY);
		mLastMotionX = x;
		mLastMotionY = y;
		mLastFocusX = focusX;
		mLastFocusY = focusY;
		mAlwaysInTapRegion = false;
		mHandler.removeMessages(TAP);
		mHandler.removeMessages(SHOW_PRESS);
		@@ -551,8 +548,8 @@ public class GestureDetector {
		}
		} else if ((Math.abs(scrollX) >= 1) \|\| (Math.abs(scrollY) >= 1)) {
		handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX, scrollY);
		mLastMotionX = x;
		mLastMotionY = y;
		mLastFocusX = focusX;
		mLastFocusY = focusY;
		}
		break;

		@@ -571,9 +568,10 @@ public class GestureDetector {

		// A fling must travel the minimum tap distance
		final VelocityTracker velocityTracker = mVelocityTracker;
		final int pointerId = ev.getPointerId(0);
		velocityTracker.computeCurrentVelocity(1000, mMaximumFlingVelocity);
		final float velocityY = velocityTracker.getYVelocity();
		final float velocityX = velocityTracker.getXVelocity();
		final float velocityY = velocityTracker.getYVelocity(pointerId);
		final float velocityX = velocityTracker.getXVelocity(pointerId);

		if ((Math.abs(velocityY) > mMinimumFlingVelocity)
		\|\| (Math.abs(velocityX) > mMinimumFlingVelocity)){
		@@ -622,6 +620,18 @@ public class GestureDetector {
		}
		}

		private void cancelTaps() {
		mHandler.removeMessages(SHOW_PRESS);
		mHandler.removeMessages(LONG_PRESS);
		mHandler.removeMessages(TAP);
		mIsDoubleTapping = false;
		mAlwaysInTapRegion = false;
		mAlwaysInBiggerTapRegion = false;
		if (mInLongPress) {
		mInLongPress = false;
		}
		}

		private boolean isConsideredDoubleTap(MotionEvent firstDown, MotionEvent firstUp,
		MotionEvent secondDown) {
		if (!mAlwaysInBiggerTapRegion) {