Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2015 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 | |
| 17 | package android.widget; |
| 18 | |
| 19 | import android.os.SystemClock; |
| 20 | import android.view.MotionEvent; |
| 21 | import android.view.View; |
| 22 | import android.view.ViewConfiguration; |
| 23 | import android.view.ViewParent; |
| 24 | |
| 25 | import com.android.internal.view.menu.ShowableListMenu; |
| 26 | |
| 27 | /** |
Oren Blasberg | b23976e | 2015-09-01 14:55:42 -0700 | [diff] [blame] | 28 | * Abstract class that forwards touch events to a {@link ShowableListMenu}. |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 29 | * |
| 30 | * @hide |
| 31 | */ |
| 32 | public abstract class ForwardingListener |
| 33 | implements View.OnTouchListener, View.OnAttachStateChangeListener { |
| 34 | |
| 35 | /** Scaled touch slop, used for detecting movement outside bounds. */ |
| 36 | private final float mScaledTouchSlop; |
| 37 | |
| 38 | /** Timeout before disallowing intercept on the source's parent. */ |
| 39 | private final int mTapTimeout; |
| 40 | |
| 41 | /** Timeout before accepting a long-press to start forwarding. */ |
| 42 | private final int mLongPressTimeout; |
| 43 | |
| 44 | /** Source view from which events are forwarded. */ |
| 45 | private final View mSrc; |
| 46 | |
| 47 | /** Runnable used to prevent conflicts with scrolling parents. */ |
| 48 | private Runnable mDisallowIntercept; |
| 49 | |
| 50 | /** Runnable used to trigger forwarding on long-press. */ |
| 51 | private Runnable mTriggerLongPress; |
| 52 | |
| 53 | /** Whether this listener is currently forwarding touch events. */ |
| 54 | private boolean mForwarding; |
| 55 | |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 56 | /** The id of the first pointer down in the current event stream. */ |
| 57 | private int mActivePointerId; |
| 58 | |
| 59 | public ForwardingListener(View src) { |
| 60 | mSrc = src; |
Alan Viverette | 11ace9e | 2016-07-21 16:04:33 -0400 | [diff] [blame] | 61 | src.setLongClickable(true); |
| 62 | src.addOnAttachStateChangeListener(this); |
| 63 | |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 64 | mScaledTouchSlop = ViewConfiguration.get(src.getContext()).getScaledTouchSlop(); |
| 65 | mTapTimeout = ViewConfiguration.getTapTimeout(); |
| 66 | |
| 67 | // Use a medium-press timeout. Halfway between tap and long-press. |
| 68 | mLongPressTimeout = (mTapTimeout + ViewConfiguration.getLongPressTimeout()) / 2; |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Returns the popup to which this listener is forwarding events. |
| 73 | * <p> |
| 74 | * Override this to return the correct popup. If the popup is displayed |
| 75 | * asynchronously, you may also need to override |
| 76 | * {@link #onForwardingStopped} to prevent premature cancellation of |
| 77 | * forwarding. |
| 78 | * |
| 79 | * @return the popup to which this listener is forwarding events |
| 80 | */ |
| 81 | public abstract ShowableListMenu getPopup(); |
| 82 | |
| 83 | @Override |
| 84 | public boolean onTouch(View v, MotionEvent event) { |
| 85 | final boolean wasForwarding = mForwarding; |
| 86 | final boolean forwarding; |
| 87 | if (wasForwarding) { |
| 88 | forwarding = onTouchForwarded(event) || !onForwardingStopped(); |
| 89 | } else { |
| 90 | forwarding = onTouchObserved(event) && onForwardingStarted(); |
| 91 | |
| 92 | if (forwarding) { |
| 93 | // Make sure we cancel any ongoing source event stream. |
| 94 | final long now = SystemClock.uptimeMillis(); |
| 95 | final MotionEvent e = MotionEvent.obtain(now, now, MotionEvent.ACTION_CANCEL, |
| 96 | 0.0f, 0.0f, 0); |
| 97 | mSrc.onTouchEvent(e); |
| 98 | e.recycle(); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | mForwarding = forwarding; |
| 103 | return forwarding || wasForwarding; |
| 104 | } |
| 105 | |
| 106 | @Override |
| 107 | public void onViewAttachedToWindow(View v) { |
| 108 | } |
| 109 | |
| 110 | @Override |
| 111 | public void onViewDetachedFromWindow(View v) { |
| 112 | mForwarding = false; |
| 113 | mActivePointerId = MotionEvent.INVALID_POINTER_ID; |
| 114 | |
| 115 | if (mDisallowIntercept != null) { |
| 116 | mSrc.removeCallbacks(mDisallowIntercept); |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Called when forwarding would like to start. |
| 122 | * <p> |
| 123 | * By default, this will show the popup returned by {@link #getPopup()}. |
| 124 | * It may be overridden to perform another action, like clicking the |
| 125 | * source view or preparing the popup before showing it. |
| 126 | * |
| 127 | * @return true to start forwarding, false otherwise |
| 128 | */ |
| 129 | protected boolean onForwardingStarted() { |
| 130 | final ShowableListMenu popup = getPopup(); |
| 131 | if (popup != null && !popup.isShowing()) { |
| 132 | popup.show(); |
| 133 | } |
| 134 | return true; |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * Called when forwarding would like to stop. |
| 139 | * <p> |
| 140 | * By default, this will dismiss the popup returned by |
| 141 | * {@link #getPopup()}. It may be overridden to perform some other |
| 142 | * action. |
| 143 | * |
| 144 | * @return true to stop forwarding, false otherwise |
| 145 | */ |
| 146 | protected boolean onForwardingStopped() { |
| 147 | final ShowableListMenu popup = getPopup(); |
| 148 | if (popup != null && popup.isShowing()) { |
| 149 | popup.dismiss(); |
| 150 | } |
| 151 | return true; |
| 152 | } |
| 153 | |
| 154 | /** |
| 155 | * Observes motion events and determines when to start forwarding. |
| 156 | * |
| 157 | * @param srcEvent motion event in source view coordinates |
| 158 | * @return true to start forwarding motion events, false otherwise |
| 159 | */ |
| 160 | private boolean onTouchObserved(MotionEvent srcEvent) { |
| 161 | final View src = mSrc; |
| 162 | if (!src.isEnabled()) { |
| 163 | return false; |
| 164 | } |
| 165 | |
| 166 | final int actionMasked = srcEvent.getActionMasked(); |
| 167 | switch (actionMasked) { |
| 168 | case MotionEvent.ACTION_DOWN: |
| 169 | mActivePointerId = srcEvent.getPointerId(0); |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 170 | |
| 171 | if (mDisallowIntercept == null) { |
| 172 | mDisallowIntercept = new DisallowIntercept(); |
| 173 | } |
| 174 | src.postDelayed(mDisallowIntercept, mTapTimeout); |
| 175 | |
| 176 | if (mTriggerLongPress == null) { |
| 177 | mTriggerLongPress = new TriggerLongPress(); |
| 178 | } |
| 179 | src.postDelayed(mTriggerLongPress, mLongPressTimeout); |
| 180 | break; |
| 181 | case MotionEvent.ACTION_MOVE: |
| 182 | final int activePointerIndex = srcEvent.findPointerIndex(mActivePointerId); |
| 183 | if (activePointerIndex >= 0) { |
| 184 | final float x = srcEvent.getX(activePointerIndex); |
| 185 | final float y = srcEvent.getY(activePointerIndex); |
| 186 | |
| 187 | // Has the pointer moved outside of the view? |
| 188 | if (!src.pointInView(x, y, mScaledTouchSlop)) { |
| 189 | clearCallbacks(); |
| 190 | |
| 191 | // Don't let the parent intercept our events. |
| 192 | src.getParent().requestDisallowInterceptTouchEvent(true); |
| 193 | return true; |
| 194 | } |
| 195 | } |
| 196 | break; |
| 197 | case MotionEvent.ACTION_CANCEL: |
| 198 | case MotionEvent.ACTION_UP: |
| 199 | clearCallbacks(); |
| 200 | break; |
| 201 | } |
| 202 | |
| 203 | return false; |
| 204 | } |
| 205 | |
| 206 | private void clearCallbacks() { |
| 207 | if (mTriggerLongPress != null) { |
| 208 | mSrc.removeCallbacks(mTriggerLongPress); |
| 209 | } |
| 210 | |
| 211 | if (mDisallowIntercept != null) { |
| 212 | mSrc.removeCallbacks(mDisallowIntercept); |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | private void onLongPress() { |
| 217 | clearCallbacks(); |
| 218 | |
| 219 | final View src = mSrc; |
| 220 | if (!src.isEnabled() || src.isLongClickable()) { |
| 221 | // Ignore long-press if the view is disabled or has its own |
| 222 | // handler. |
| 223 | return; |
| 224 | } |
| 225 | |
| 226 | if (!onForwardingStarted()) { |
| 227 | return; |
| 228 | } |
| 229 | |
| 230 | // Don't let the parent intercept our events. |
| 231 | src.getParent().requestDisallowInterceptTouchEvent(true); |
| 232 | |
| 233 | // Make sure we cancel any ongoing source event stream. |
| 234 | final long now = SystemClock.uptimeMillis(); |
| 235 | final MotionEvent e = MotionEvent.obtain(now, now, MotionEvent.ACTION_CANCEL, 0, 0, 0); |
| 236 | src.onTouchEvent(e); |
| 237 | e.recycle(); |
| 238 | |
| 239 | mForwarding = true; |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 240 | } |
| 241 | |
| 242 | /** |
| 243 | * Handles forwarded motion events and determines when to stop |
| 244 | * forwarding. |
| 245 | * |
| 246 | * @param srcEvent motion event in source view coordinates |
| 247 | * @return true to continue forwarding motion events, false to cancel |
| 248 | */ |
| 249 | private boolean onTouchForwarded(MotionEvent srcEvent) { |
| 250 | final View src = mSrc; |
| 251 | final ShowableListMenu popup = getPopup(); |
| 252 | if (popup == null || !popup.isShowing()) { |
| 253 | return false; |
| 254 | } |
| 255 | |
| 256 | final DropDownListView dst = (DropDownListView) popup.getListView(); |
| 257 | if (dst == null || !dst.isShown()) { |
| 258 | return false; |
| 259 | } |
| 260 | |
| 261 | // Convert event to destination-local coordinates. |
| 262 | final MotionEvent dstEvent = MotionEvent.obtainNoHistory(srcEvent); |
| 263 | src.toGlobalMotionEvent(dstEvent); |
| 264 | dst.toLocalMotionEvent(dstEvent); |
| 265 | |
| 266 | // Forward converted event to destination view, then recycle it. |
| 267 | final boolean handled = dst.onForwardedEvent(dstEvent, mActivePointerId); |
| 268 | dstEvent.recycle(); |
| 269 | |
| 270 | // Always cancel forwarding when the touch stream ends. |
| 271 | final int action = srcEvent.getActionMasked(); |
| 272 | final boolean keepForwarding = action != MotionEvent.ACTION_UP |
| 273 | && action != MotionEvent.ACTION_CANCEL; |
| 274 | |
| 275 | return handled && keepForwarding; |
| 276 | } |
| 277 | |
| 278 | private class DisallowIntercept implements Runnable { |
| 279 | @Override |
| 280 | public void run() { |
| 281 | final ViewParent parent = mSrc.getParent(); |
Chris Banes | b62db80 | 2016-07-11 16:41:43 +0100 | [diff] [blame] | 282 | if (parent != null) { |
| 283 | parent.requestDisallowInterceptTouchEvent(true); |
| 284 | } |
Oren Blasberg | f44d90b | 2015-08-31 14:15:26 -0700 | [diff] [blame] | 285 | } |
| 286 | } |
| 287 | |
| 288 | private class TriggerLongPress implements Runnable { |
| 289 | @Override |
| 290 | public void run() { |
| 291 | onLongPress(); |
| 292 | } |
| 293 | } |
Chris Banes | b62db80 | 2016-07-11 16:41:43 +0100 | [diff] [blame] | 294 | } |