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Commit 05a1e1f6 authored by Adam Powell's avatar Adam Powell
Browse files

Use focal point for scrolling in GestureDetector 

Remove workaround for obsolete touchscreen hardware. Provide a better
focal point for scroll events.

Change-Id: I879acb4cfd23bd3762d0332e4df2203d913ae869
parent d5ea3b46

core/java/android/view/GestureDetector.java

+64 −54
Original line number Original line Diff line number Diff line
@@ -226,18 +226,13 @@ public class GestureDetector { 
     */

     */

    private boolean mIsDoubleTapping;

    private boolean mIsDoubleTapping;





    private float mLastMotionY;

    private float mLastFocusX;

    private float mLastMotionX;

    private float mLastFocusY;

    private float mDownFocusX;

    private float mDownFocusY;





    private boolean mIsLongpressEnabled;

    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

     * Determines speed during touch scrolling

     */

     */
@@ -349,8 +344,16 @@ public class GestureDetector { 
     * @throws NullPointerException if {@code listener} is null.

     * @throws NullPointerException if {@code listener} is null.

     */

     */

    public GestureDetector(Context context, OnGestureListener listener, Handler handler) {

    public GestureDetector(Context context, OnGestureListener listener, Handler handler) {

        this(context, listener, handler, context != null &&

        if (handler != null) {

                context.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.FROYO);

            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

     * @param listener the listener invoked for all the callbacks, this must

     * not be null.

     * not be null.

     * @param handler the handler to use

     * @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.

     * @throws NullPointerException if {@code listener} is null.

     */

     */

    public GestureDetector(Context context, OnGestureListener listener, Handler handler,

    public GestureDetector(Context context, OnGestureListener listener, Handler handler,

            boolean ignoreMultitouch) {

            boolean unused) {

        if (handler != null) {

        this(context, listener, handler);

            mHandler = new GestureHandler(handler);

        } else {

            mHandler = new GestureHandler();

        }

        mListener = listener;

        if (listener instanceof OnDoubleTapListener) {

            setOnDoubleTapListener((OnDoubleTapListener) listener);

        }

        init(context, ignoreMultitouch);

    }

    }





    private void init(Context context, boolean ignoreMultitouch) {

    private void init(Context context) {

        if (mListener == null) {

        if (mListener == null) {

            throw new NullPointerException("OnGestureListener must not be null");

            throw new NullPointerException("OnGestureListener must not be null");

        }

        }

        mIsLongpressEnabled = true;

        mIsLongpressEnabled = true;

        mIgnoreMultitouch = ignoreMultitouch;





        // Fallback to support pre-donuts releases

        // Fallback to support pre-donuts releases

        int touchSlop, doubleTapSlop, doubleTapTouchSlop;

        int touchSlop, doubleTapSlop, doubleTapTouchSlop;
@@ -456,34 +447,40 @@ public class GestureDetector { 
        }

        }





        final int action = ev.getAction();

        final int action = ev.getAction();

        final float y = ev.getY();

        final float x = ev.getX();





        if (mVelocityTracker == null) {

        if (mVelocityTracker == null) {

            mVelocityTracker = VelocityTracker.obtain();

            mVelocityTracker = VelocityTracker.obtain();

        }

        }

        mVelocityTracker.addMovement(ev);

        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;

        boolean handled = false;





        switch (action & MotionEvent.ACTION_MASK) {

        switch (action & MotionEvent.ACTION_MASK) {

        case MotionEvent.ACTION_POINTER_DOWN:

        case MotionEvent.ACTION_POINTER_DOWN:

            if (mIgnoreMultitouch) {

            mDownFocusX = mLastFocusX = focusX;

                // Multitouch event - abort.

            mDownFocusY = mLastFocusY = focusY;

                cancel();

            // Cancel long press and taps

            }

            cancelTaps();

            break;

            break;





        case MotionEvent.ACTION_POINTER_UP:

        case MotionEvent.ACTION_POINTER_UP:

            // Ending a multitouch gesture and going back to 1 finger

            mDownFocusX = mLastFocusX = focusX;

            if (mIgnoreMultitouch && ev.getPointerCount() == 2) {

            mDownFocusY = mLastFocusY = focusY;

                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();

            }

            break;

            break;





        case MotionEvent.ACTION_DOWN:

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

                }

            }

            }





            mLastMotionX = x;

            mDownFocusX = mLastFocusX = focusX;

            mLastMotionY = y;

            mDownFocusY = mLastFocusY = focusY;

            if (mCurrentDownEvent != null) {

            if (mCurrentDownEvent != null) {

                mCurrentDownEvent.recycle();

                mCurrentDownEvent.recycle();

            }

            }
@@ -525,22 +522,22 @@ public class GestureDetector { 
            break;

            break;





        case MotionEvent.ACTION_MOVE:

        case MotionEvent.ACTION_MOVE:

            if (mInLongPress || (mIgnoreMultitouch && ev.getPointerCount() > 1)) {

            if (mInLongPress) {

                break;

                break;

            }

            }

            final float scrollX = mLastMotionX - x;

            final float scrollX = mLastFocusX - focusX;

            final float scrollY = mLastMotionY - y;

            final float scrollY = mLastFocusY - focusY;

            if (mIsDoubleTapping) {

            if (mIsDoubleTapping) {

                // Give the move events of the double-tap

                // Give the move events of the double-tap

                handled |= mDoubleTapListener.onDoubleTapEvent(ev);

                handled |= mDoubleTapListener.onDoubleTapEvent(ev);

            } else if (mAlwaysInTapRegion) {

            } else if (mAlwaysInTapRegion) {

                final int deltaX = (int) (x - mCurrentDownEvent.getX());

                final int deltaX = (int) (focusX - mDownFocusX);

                final int deltaY = (int) (y - mCurrentDownEvent.getY());

                final int deltaY = (int) (focusY - mDownFocusY);

                int distance = (deltaX * deltaX) + (deltaY * deltaY);

                int distance = (deltaX * deltaX) + (deltaY * deltaY);

                if (distance > mTouchSlopSquare) {

                if (distance > mTouchSlopSquare) {

                    handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX, scrollY);

                    handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX, scrollY);

                    mLastMotionX = x;

                    mLastFocusX = focusX;

                    mLastMotionY = y;

                    mLastFocusY = focusY;

                    mAlwaysInTapRegion = false;

                    mAlwaysInTapRegion = false;

                    mHandler.removeMessages(TAP);

                    mHandler.removeMessages(TAP);

                    mHandler.removeMessages(SHOW_PRESS);

                    mHandler.removeMessages(SHOW_PRESS);
@@ -551,8 +548,8 @@ public class GestureDetector { 
                }

                }

            } else if ((Math.abs(scrollX) >= 1) || (Math.abs(scrollY) >= 1)) {

            } else if ((Math.abs(scrollX) >= 1) || (Math.abs(scrollY) >= 1)) {

                handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX, scrollY);

                handled = mListener.onScroll(mCurrentDownEvent, ev, scrollX, scrollY);

                mLastMotionX = x;

                mLastFocusX = focusX;

                mLastMotionY = y;

                mLastFocusY = focusY;

            }

            }

            break;

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




                // A fling must travel the minimum tap distance

                // A fling must travel the minimum tap distance

                final VelocityTracker velocityTracker = mVelocityTracker;

                final VelocityTracker velocityTracker = mVelocityTracker;

                final int pointerId = ev.getPointerId(0);

                velocityTracker.computeCurrentVelocity(1000, mMaximumFlingVelocity);

                velocityTracker.computeCurrentVelocity(1000, mMaximumFlingVelocity);

                final float velocityY = velocityTracker.getYVelocity();

                final float velocityY = velocityTracker.getYVelocity(pointerId);

                final float velocityX = velocityTracker.getXVelocity();

                final float velocityX = velocityTracker.getXVelocity(pointerId);





                if ((Math.abs(velocityY) > mMinimumFlingVelocity)

                if ((Math.abs(velocityY) > mMinimumFlingVelocity)

                        || (Math.abs(velocityX) > 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,

    private boolean isConsideredDoubleTap(MotionEvent firstDown, MotionEvent firstUp,

            MotionEvent secondDown) {

            MotionEvent secondDown) {

        if (!mAlwaysInBiggerTapRegion) {

        if (!mAlwaysInBiggerTapRegion) {