| 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | package org.chromium.content.browser; |
| 6 | |
| 7 | import android.content.Context; |
| 8 | import android.os.Handler; |
| 9 | import android.os.Message; |
| 10 | import android.view.MotionEvent; |
| 11 | import android.view.ViewConfiguration; |
| 12 | |
| 13 | import java.util.Iterator; |
| 14 | |
| 15 | /** |
| 16 | * This class controls long press timers and is owned by a ContentViewGestureHandler. |
| 17 | * |
| 18 | * For instance, we may receive a DOWN then UP, so we may need to cancel the |
| 19 | * timer before the UP completes its roundtrip from WebKit. |
| 20 | */ |
| 21 | class LongPressDetector { |
| 22 | private MotionEvent mCurrentDownEvent; |
| 23 | private final LongPressDelegate mLongPressDelegate; |
| 24 | private final Handler mLongPressHandler; |
| 25 | private final int mTouchSlopSquare; |
| 26 | private boolean mInLongPress; |
| 27 | |
| 28 | // The following are used when touch events are offered to native, and not for |
| 29 | // anything relating to the GestureDetector. |
| 30 | // True iff a touch_move has exceeded the touch slop distance. |
| 31 | private boolean mMoveConfirmed; |
| 32 | // Coordinates of the start of a touch event (i.e. the touch_down). |
| 33 | private int mTouchInitialX; |
| 34 | private int mTouchInitialY; |
| 35 | |
| 36 | private static final int LONG_PRESS = 2; |
| 37 | |
| 38 | private static final int LONGPRESS_TIMEOUT = ViewConfiguration.getLongPressTimeout(); |
| 39 | private static final int TAP_TIMEOUT = ViewConfiguration.getTapTimeout(); |
| 40 | |
| 41 | LongPressDetector(Context context, LongPressDelegate delegate) { |
| 42 | mLongPressDelegate = delegate; |
| 43 | mLongPressHandler = new LongPressHandler(); |
| 44 | final ViewConfiguration configuration = ViewConfiguration.get(context); |
| 45 | int touchSlop = configuration.getScaledTouchSlop(); |
| 46 | mTouchSlopSquare = touchSlop * touchSlop; |
| 47 | } |
| 48 | |
| 49 | private class LongPressHandler extends Handler { |
| 50 | LongPressHandler() { |
| 51 | super(); |
| 52 | } |
| 53 | |
| 54 | @Override |
| 55 | public void handleMessage(Message msg) { |
| 56 | switch (msg.what) { |
| 57 | case LONG_PRESS: |
| 58 | dispatchLongPress(); |
| 59 | break; |
| 60 | default: |
| 61 | throw new RuntimeException("Unknown message " + msg); //never |
| 62 | } |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * This is an interface to execute the LongPress when it receives the onLongPress message. |
| 68 | */ |
| 69 | interface LongPressDelegate { |
| 70 | /** |
| 71 | * @param event The event will be recycled after this call has returned. |
| 72 | */ |
| 73 | public void onLongPress(MotionEvent event); |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * Initiates a LONG_PRESS gesture timer if needed. |
| 78 | */ |
| 79 | void startLongPressTimerIfNeeded(MotionEvent ev) { |
| 80 | if (ev.getAction() != MotionEvent.ACTION_DOWN) return; |
| 81 | |
| 82 | // If there is a current down, we do not expect another down event before |
| 83 | // receiving an up event |
| 84 | if (mCurrentDownEvent != null) return; |
| 85 | |
| 86 | mCurrentDownEvent = MotionEvent.obtain(ev); |
| 87 | mLongPressHandler.sendEmptyMessageAtTime(LONG_PRESS, mCurrentDownEvent.getDownTime() |
| 88 | + TAP_TIMEOUT + LONGPRESS_TIMEOUT); |
| 89 | mInLongPress = false; |
| 90 | } |
| 91 | |
| 92 | // Cancel LONG_PRESS timers. |
| 93 | void cancelLongPressIfNeeded(MotionEvent ev) { |
| 94 | if (!hasPendingMessage() || |
| 95 | mCurrentDownEvent == null || ev.getDownTime() != mCurrentDownEvent.getDownTime()) { |
| 96 | return; |
| 97 | } |
| 98 | final int action = ev.getAction(); |
| 99 | final float y = ev.getY(); |
| 100 | final float x = ev.getX(); |
| 101 | switch (action & MotionEvent.ACTION_MASK) { |
| 102 | case MotionEvent.ACTION_MOVE: |
| 103 | final int deltaX = (int) (x - mCurrentDownEvent.getX()); |
| 104 | final int deltaY = (int) (y - mCurrentDownEvent.getY()); |
| 105 | int distance = (deltaX * deltaX) + (deltaY * deltaY); |
| 106 | if (distance > mTouchSlopSquare) { |
| 107 | cancelLongPress(); |
| 108 | } |
| 109 | break; |
| 110 | case MotionEvent.ACTION_UP: |
| 111 | case MotionEvent.ACTION_CANCEL: |
| 112 | if (mCurrentDownEvent.getDownTime() + TAP_TIMEOUT + LONGPRESS_TIMEOUT > |
| 113 | ev.getEventTime()) { |
| 114 | cancelLongPress(); |
| 115 | } |
| 116 | break; |
| 117 | default: |
| 118 | break; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | // Given a stream of pending events, cancel the LONG_PRESS timer if appropriate. |
| 123 | void cancelLongPressIfNeeded(Iterator<MotionEvent> pendingEvents) { |
| 124 | if (mCurrentDownEvent == null) |
| 125 | return; |
| 126 | long currentDownTime = mCurrentDownEvent.getDownTime(); |
| 127 | while (pendingEvents.hasNext()) { |
| 128 | MotionEvent pending = pendingEvents.next(); |
| 129 | if (pending.getDownTime() != currentDownTime) { |
| 130 | break; |
| 131 | } |
| 132 | cancelLongPressIfNeeded(pending); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | void cancelLongPress() { |
| 137 | mInLongPress = false; |
| 138 | if (hasPendingMessage()) { |
| 139 | mLongPressHandler.removeMessages(LONG_PRESS); |
| 140 | mCurrentDownEvent.recycle(); |
| 141 | mCurrentDownEvent = null; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | // Used this to check if a onSingleTapUp is part of a long press event. |
| 146 | boolean isInLongPress() { |
| 147 | return mInLongPress; |
| 148 | } |
| 149 | |
| 150 | private void dispatchLongPress() { |
| 151 | mInLongPress = true; |
| 152 | mLongPressDelegate.onLongPress(mCurrentDownEvent); |
| 153 | mCurrentDownEvent.recycle(); |
| 154 | mCurrentDownEvent = null; |
| 155 | } |
| 156 | |
| 157 | boolean hasPendingMessage() { |
| 158 | return mCurrentDownEvent != null; |
| 159 | } |
| 160 | |
| 161 | void onOfferTouchEventToJavaScript(MotionEvent event) { |
| 162 | if (event.getActionMasked() == MotionEvent.ACTION_DOWN) { |
| 163 | mMoveConfirmed = false; |
| 164 | mTouchInitialX = Math.round(event.getX()); |
| 165 | mTouchInitialY = Math.round(event.getY()); |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | boolean confirmOfferMoveEventToJavaScript(MotionEvent event) { |
| 170 | if (!mMoveConfirmed) { |
| 171 | int deltaX = Math.round(event.getX()) - mTouchInitialX; |
| 172 | int deltaY = Math.round(event.getY()) - mTouchInitialY; |
| 173 | if (deltaX * deltaX + deltaY * deltaY >= mTouchSlopSquare) { |
| 174 | mMoveConfirmed = true; |
| 175 | } |
| 176 | } |
| 177 | return mMoveConfirmed; |
| 178 | } |
| 179 | |
| 180 | /** |
| 181 | * This is for testing only. |
| 182 | * Sends a LongPress gesture. This should always be called after a down event. |
| 183 | */ |
| 184 | void sendLongPressGestureForTest() { |
| 185 | if (mCurrentDownEvent == null) return; |
| 186 | dispatchLongPress(); |
| 187 | } |
| 188 | } |