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Commit 40b8b01d authored by Adam Powell's avatar Adam Powell Committed by The Android Automerger
Browse files

ScaleGestureDetector does the safety dance. 

Warn in the event of possibly bogus event streams and don't try to
clear empty history.

Bug 7241640
Bug 7243006

Change-Id: I037cf1334cab790ef5998ca5f8f6b323ed5f4459
parent 91c5c21d

core/java/android/view/ScaleGestureDetector.java

+20 −2
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ package android.view; 
import android.content.Context;

import android.os.SystemClock;

import android.util.FloatMath;

import android.util.Log;



import java.util.Arrays;
@@ -223,10 +224,14 @@ public class ScaleGestureDetector { 
     * @param id pointer id to clear

     * @see #addTouchHistory(MotionEvent)

     */

    private void removeTouchHistoryForId(int id) {

    private boolean removeTouchHistoryForId(int id) {

        if (id >= mTouchHistoryLastAccepted.length) {

            return false;

        }

        mTouchHistoryLastAccepted[id] = Float.NaN;

        mTouchHistoryDirection[id] = 0;

        mTouchHistoryLastAcceptedTime[id] = 0;

        return true;

    }



    /**
@@ -236,6 +241,11 @@ public class ScaleGestureDetector { 
     * @see #addTouchHistory(MotionEvent)

     */

    private float getAdjustedTouchHistory(int id) {

        if (id >= mTouchHistoryLastAccepted.length) {

            Log.e(TAG, "Error retrieving adjusted touch history for id=" + id +

                    " - incomplete event stream?");

            return 0;

        }

        return mTouchHistoryLastAccepted[id];

    }
@@ -244,6 +254,10 @@ public class ScaleGestureDetector { 
     * @see #addTouchHistory(MotionEvent)

     */

    private void clearTouchHistory() {

        if (mTouchHistoryLastAccepted == null) {

            // All three arrays will be null if this is the case; nothing to do.

            return;

        }

        Arrays.fill(mTouchHistoryLastAccepted, Float.NaN);

        Arrays.fill(mTouchHistoryDirection, 0);

        Arrays.fill(mTouchHistoryLastAcceptedTime, 0);
@@ -333,7 +347,11 @@ public class ScaleGestureDetector { 
        final float focusY = sumY / div;



        if (pointerUp) {

            removeTouchHistoryForId(event.getPointerId(event.getActionIndex()));

            final int id = event.getPointerId(event.getActionIndex());

            if (!removeTouchHistoryForId(id)) {

                Log.e(TAG, "Got ACTION_POINTER_UP for previously unknown id=" + id +

                        " - incomplete event stream?");

            }

        } else {

            addTouchHistory(event);

        }