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Commit 88b869a4 authored by Huahui Wu's avatar Huahui Wu
Browse files

b/4116658 Fix the jumpy scrolling with some flash site. 

In the case that a touch event is passed to WebKit then back to
WebView, the coordinates will be converted from view to content
then back to view and the convertion could lose some accuracies.
For a flash content that only consumes TouchDown, all the
TouchMove events will go through this path and each time, the
data becomes more inaccurate. Even worse, the TouchMove event
updates the mScrollX/Y which will then be used for the convertion.
The effect amplifies really quick and the scrolling looks jumpy.

The fix is just to store the original view coordinates when pass
the event around.

Change-Id: Ie1424d7cfc6272348b194732e97168efe2dcf17b
parent 11473332

core/java/android/webkit/WebView.java

+24 −9
Original line number Diff line number Diff line
@@ -1672,6 +1672,7 @@ public class WebView extends AbsoluteLayout 


        mDrawHistory = true;

        mHistoryPicture = p;



        mScrollX = sx;

        mScrollY = sy;

        mZoomManager.restoreZoomState(b);
@@ -5473,7 +5474,6 @@ public class WebView extends AbsoluteLayout 
    private boolean handleTouchEventCommon(MotionEvent ev, int action, int x, int y) {

        long eventTime = ev.getEventTime();





        // Due to the touch screen edge effect, a touch closer to the edge

        // always snapped to the edge. As getViewWidth() can be different from

        // getWidth() due to the scrollbar, adjusting the point to match
@@ -5577,6 +5577,8 @@ public class WebView extends AbsoluteLayout 
                        ted.mIds[0] = ev.getPointerId(0);

                        ted.mPoints = new Point[1];

                        ted.mPoints[0] = new Point(contentX, contentY);

                        ted.mPointsInView = new Point[1];

                        ted.mPointsInView[0] = new Point(x, y);

                        ted.mMetaState = ev.getMetaState();

                        ted.mReprocess = mDeferTouchProcess;

                        ted.mNativeLayer = nativeScrollableLayer(
@@ -5624,6 +5626,8 @@ public class WebView extends AbsoluteLayout 
                    ted.mIds[0] = ev.getPointerId(0);

                    ted.mPoints = new Point[1];

                    ted.mPoints[0] = new Point(contentX, contentY);

                    ted.mPointsInView = new Point[1];

                    ted.mPointsInView[0] = new Point(x, y);

                    ted.mMetaState = ev.getMetaState();

                    ted.mReprocess = mDeferTouchProcess;

                    ted.mNativeLayer = mScrollingLayer;
@@ -5806,6 +5810,8 @@ public class WebView extends AbsoluteLayout 
                    ted.mAction = action;

                    ted.mPoints = new Point[1];

                    ted.mPoints[0] = new Point(contentX, contentY);

                    ted.mPointsInView = new Point[1];

                    ted.mPointsInView[0] = new Point(x, y);

                    ted.mMetaState = ev.getMetaState();

                    ted.mReprocess = mDeferTouchProcess;

                    ted.mNativeLayer = mScrollingLayer;
@@ -5828,6 +5834,8 @@ public class WebView extends AbsoluteLayout 
                            ted.mAction = WebViewCore.ACTION_DOUBLETAP;

                            ted.mPoints = new Point[1];

                            ted.mPoints[0] = new Point(contentX, contentY);

                            ted.mPointsInView = new Point[1];

                            ted.mPointsInView[0] = new Point(x, y);

                            ted.mMetaState = ev.getMetaState();

                            ted.mReprocess = mDeferTouchProcess;

                            ted.mNativeLayer = nativeScrollableLayer(
@@ -5964,11 +5972,13 @@ public class WebView extends AbsoluteLayout 
        final int count = ev.getPointerCount();

        ted.mIds = new int[count];

        ted.mPoints = new Point[count];

        ted.mPointsInView = new Point[count];

        for (int c = 0; c < count; c++) {

            ted.mIds[c] = ev.getPointerId(c);

            int x = viewToContentX((int) ev.getX(c) + mScrollX);

            int y = viewToContentY((int) ev.getY(c) + mScrollY);

            ted.mPoints[c] = new Point(x, y);

            ted.mPointsInView[c] = new Point((int) ev.getX(c), (int) ev.getY(c));

        }

        if (ted.mAction == MotionEvent.ACTION_POINTER_DOWN

            || ted.mAction == MotionEvent.ACTION_POINTER_UP) {
@@ -6053,6 +6063,10 @@ public class WebView extends AbsoluteLayout 
            ted.mIds[0] = 0;

            ted.mPoints = new Point[1];

            ted.mPoints[0] = new Point(x, y);

            ted.mPointsInView = new Point[1];

            int viewX = contentToViewX(x) - mScrollX;

            int viewY = contentToViewY(y) - mScrollY;

            ted.mPointsInView[0] = new Point(viewX, viewY);

            ted.mAction = MotionEvent.ACTION_CANCEL;

            ted.mNativeLayer = nativeScrollableLayer(

                    x, y, ted.mNativeLayerRect, null);
@@ -7441,16 +7455,15 @@ public class WebView extends AbsoluteLayout 
                    // Following is for single touch.

                    switch (ted.mAction) {

                        case MotionEvent.ACTION_DOWN:

                            mLastDeferTouchX = contentToViewX(ted.mPoints[0].x)

                                    - mScrollX;

                            mLastDeferTouchY = contentToViewY(ted.mPoints[0].y)

                                    - mScrollY;

                            mLastDeferTouchX = ted.mPointsInView[0].x;

                            mLastDeferTouchY = ted.mPointsInView[0].y;

                            mDeferTouchMode = TOUCH_INIT_MODE;

                            break;

                        case MotionEvent.ACTION_MOVE: {

                            // no snapping in defer process

                            int x = contentToViewX(ted.mPoints[0].x) - mScrollX;

                            int y = contentToViewY(ted.mPoints[0].y) - mScrollY;

                            int x = ted.mPointsInView[0].x;

                            int y = ted.mPointsInView[0].y;



                            if (mDeferTouchMode != TOUCH_DRAG_MODE) {

                                mDeferTouchMode = TOUCH_DRAG_MODE;

                                mLastDeferTouchX = x;
@@ -7484,8 +7497,8 @@ public class WebView extends AbsoluteLayout 
                            break;

                        case WebViewCore.ACTION_DOUBLETAP:

                            // doDoubleTap() needs mLastTouchX/Y as anchor

                            mLastTouchX = contentToViewX(ted.mPoints[0].x) - mScrollX;

                            mLastTouchY = contentToViewY(ted.mPoints[0].y) - mScrollY;

                            mLastDeferTouchX = ted.mPointsInView[0].x;

                            mLastDeferTouchY = ted.mPointsInView[0].y;

                            mZoomManager.handleDoubleTap(mLastTouchX, mLastTouchY);

                            mDeferTouchMode = TOUCH_DONE_MODE;

                            break;
@@ -7609,6 +7622,8 @@ public class WebView extends AbsoluteLayout 
                        ted.mPoints = new Point[1];

                        ted.mPoints[0] = new Point(viewToContentX(mLastTouchX + mScrollX),

                                                   viewToContentY(mLastTouchY + mScrollY));

                        ted.mPointsInView = new Point[1];

                        ted.mPointsInView[0] = new Point(mLastTouchX, mLastTouchY);

                        // metaState for long press is tricky. Should it be the

                        // state when the press started or when the press was

                        // released? Or some intermediary key state? For

core/java/android/webkit/WebViewCore.java

+1 −0
Original line number Diff line number Diff line
@@ -831,6 +831,7 @@ final class WebViewCore { 
        int mAction;

        int[] mIds;  // Ids of the touch points

        Point[] mPoints;

        Point[] mPointsInView;  // the point coordinates in view axis.

        int mActionIndex;  // Associated pointer index for ACTION_POINTER_DOWN/UP

        int mMetaState;

        boolean mReprocess;