NonDistinctMultitouchHelper.java revision e08c418ff8b374244677960903cee8dd52a4d831 
1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.inputmethod.keyboard.internal;
18
19import android.util.Log;
20import android.view.MotionEvent;
21
22import com.android.inputmethod.keyboard.Key;
23import com.android.inputmethod.keyboard.PointerTracker;
24import com.android.inputmethod.keyboard.PointerTracker.KeyEventHandler;
25import com.android.inputmethod.latin.utils.CoordinateUtils;
26
27public final class NonDistinctMultitouchHelper {
28    private static final String TAG = NonDistinctMultitouchHelper.class.getSimpleName();
29
30    private int mOldPointerCount = 1;
31    private Key mOldKey;
32    private int[] mLastCoords = CoordinateUtils.newInstance();
33
34    public void processMotionEvent(final MotionEvent me, final KeyEventHandler keyEventHandler) {
35        final int pointerCount = me.getPointerCount();
36        final int oldPointerCount = mOldPointerCount;
37        mOldPointerCount = pointerCount;
38        // Ignore continuous multi-touch events because we can't trust the coordinates
39        // in multi-touch events.
40        if (pointerCount > 1 && oldPointerCount > 1) {
41            return;
42        }
43
44        // Use only main (id=0) pointer tracker.
45        final PointerTracker mainTracker = PointerTracker.getPointerTracker(0, keyEventHandler);
46        final int action = me.getActionMasked();
47        final int index = me.getActionIndex();
48        final long eventTime = me.getEventTime();
49        final long downTime = me.getDownTime();
50
51        // In single-touch.
52        if (oldPointerCount == 1 && pointerCount == 1) {
53            if (me.getPointerId(index) == mainTracker.mPointerId) {
54                mainTracker.processMotionEvent(me, keyEventHandler);
55                return;
56            }
57            // Inject a copied event.
58            injectMotionEvent(action, me.getX(index), me.getY(index), downTime, eventTime,
59                    mainTracker, keyEventHandler);
60            return;
61        }
62
63        // Single-touch to multi-touch transition.
64        if (oldPointerCount == 1 && pointerCount == 2) {
65            // Send an up event for the last pointer, be cause we can't trust the coordinates of
66            // this multi-touch event.
67            mainTracker.getLastCoordinates(mLastCoords);
68            final int x = CoordinateUtils.x(mLastCoords);
69            final int y = CoordinateUtils.y(mLastCoords);
70            mOldKey = mainTracker.getKeyOn(x, y);
71            // Inject an artifact up event for the old key.
72            injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
73                    mainTracker, keyEventHandler);
74            return;
75        }
76
77        // Multi-touch to single-touch transition.
78        if (oldPointerCount == 2 && pointerCount == 1) {
79            // Send a down event for the latest pointer if the key is different from the previous
80            // key.
81            final int x = (int)me.getX(index);
82            final int y = (int)me.getY(index);
83            final Key newKey = mainTracker.getKeyOn(x, y);
84            if (mOldKey != newKey) {
85                // Inject an artifact down event for the new key.
86                // An artifact up event for the new key will usually be injected as a single-touch.
87                injectMotionEvent(MotionEvent.ACTION_DOWN, x, y, downTime, eventTime,
88                        mainTracker, keyEventHandler);
89                if (action == MotionEvent.ACTION_UP) {
90                    // Inject an artifact up event for the new key also.
91                    injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
92                            mainTracker, keyEventHandler);
93                }
94            }
95            return;
96        }
97
98        Log.w(TAG, "Unknown touch panel behavior: pointer count is "
99                + pointerCount + " (previously " + oldPointerCount + ")");
100    }
101
102    private static void injectMotionEvent(final int action, final float x, final float y,
103            final long downTime, final long eventTime, final PointerTracker tracker,
104            final KeyEventHandler handler) {
105        final MotionEvent me = MotionEvent.obtain(
106                downTime, eventTime, action, x, y, 0 /* metaState */);
107        try {
108            tracker.processMotionEvent(me, handler);
109        } finally {
110            me.recycle();
111        }
112    }
113}
114