1/* 2 * Copyright (C) 2012 Google Inc. 3 * Licensed to The Android Open Source Project. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18package com.android.mail.ui; 19 20import android.animation.Animator; 21import android.animation.AnimatorListenerAdapter; 22import android.animation.ObjectAnimator; 23import android.animation.ValueAnimator; 24import android.animation.ValueAnimator.AnimatorUpdateListener; 25import android.content.Context; 26import android.content.res.Resources; 27import android.graphics.RectF; 28import android.view.MotionEvent; 29import android.view.VelocityTracker; 30import android.view.View; 31import android.view.animation.DecelerateInterpolator; 32 33import com.android.mail.R; 34import com.android.mail.utils.LogUtils; 35import com.android.mail.utils.Utils; 36 37public class SwipeHelper { 38 static final String TAG = "com.android.systemui.SwipeHelper"; 39 private static final boolean DEBUG_INVALIDATE = false; 40 private static final boolean CONSTRAIN_SWIPE = true; 41 private static final boolean FADE_OUT_DURING_SWIPE = true; 42 private static final boolean DISMISS_IF_SWIPED_FAR_ENOUGH = true; 43 // Turn on for debugging only during development. 44 private static final boolean LOG_SWIPE_DISMISS_VELOCITY = false; 45 46 public static final int X = 0; 47 public static final int Y = 1; 48 49 private static DecelerateInterpolator sDecelerateInterpolator = 50 new DecelerateInterpolator(1.0f); 51 52 private static int SWIPE_ESCAPE_VELOCITY = -1; 53 private static int DEFAULT_ESCAPE_ANIMATION_DURATION; 54 private static int MAX_ESCAPE_ANIMATION_DURATION; 55 private static int MAX_DISMISS_VELOCITY; 56 private static int SNAP_ANIM_LEN; 57 private static float MIN_SWIPE; 58 59 public static float ALPHA_FADE_START = 0f; // fraction of thumbnail width 60 // where fade starts 61 public static float ALPHA_TEXT_FADE_START = 0.4f; 62 static final float ALPHA_FADE_END = 0.7f; // fraction of thumbnail width 63 // beyond which alpha->0 64 private static final float FACTOR = 1.2f; 65 66 /* Dead region where swipe cannot be initiated. */ 67 private final static int DEAD_REGION_FOR_SWIPE = 56; 68 69 private float mPagingTouchSlop; 70 private final Callback mCallback; 71 private final int mSwipeDirection; 72 private final VelocityTracker mVelocityTracker; 73 74 private float mInitialTouchPosX; 75 private boolean mDragging; 76 private SwipeableItemView mCurrView; 77 private View mCurrAnimView; 78 private boolean mCanCurrViewBeDimissed; 79 private float mDensityScale; 80 private float mLastY; 81 private float mInitialTouchPosY; 82 private LeaveBehindItem mPrevView; 83 84 public SwipeHelper(Context context, int swipeDirection, Callback callback, float densityScale, 85 float pagingTouchSlop) { 86 mCallback = callback; 87 mSwipeDirection = swipeDirection; 88 mVelocityTracker = VelocityTracker.obtain(); 89 mDensityScale = densityScale; 90 mPagingTouchSlop = pagingTouchSlop; 91 if (SWIPE_ESCAPE_VELOCITY == -1) { 92 Resources res = context.getResources(); 93 SWIPE_ESCAPE_VELOCITY = res.getInteger(R.integer.swipe_escape_velocity); 94 DEFAULT_ESCAPE_ANIMATION_DURATION = res.getInteger(R.integer.escape_animation_duration); 95 MAX_ESCAPE_ANIMATION_DURATION = res.getInteger(R.integer.max_escape_animation_duration); 96 MAX_DISMISS_VELOCITY = res.getInteger(R.integer.max_dismiss_velocity); 97 SNAP_ANIM_LEN = res.getInteger(R.integer.snap_animation_duration); 98 MIN_SWIPE = res.getDimension(R.dimen.min_swipe); 99 } 100 } 101 102 public void setDensityScale(float densityScale) { 103 mDensityScale = densityScale; 104 } 105 106 public void setPagingTouchSlop(float pagingTouchSlop) { 107 mPagingTouchSlop = pagingTouchSlop; 108 } 109 110 private float getVelocity(VelocityTracker vt) { 111 return mSwipeDirection == X ? vt.getXVelocity() : 112 vt.getYVelocity(); 113 } 114 115 private ObjectAnimator createTranslationAnimation(View v, float newPos) { 116 ObjectAnimator anim = ObjectAnimator.ofFloat(v, 117 mSwipeDirection == X ? "translationX" : "translationY", newPos); 118 return anim; 119 } 120 121 private ObjectAnimator createDismissAnimation(View v, float newPos, int duration) { 122 ObjectAnimator anim = createTranslationAnimation(v, newPos); 123 anim.setInterpolator(sDecelerateInterpolator); 124 anim.setDuration(duration); 125 return anim; 126 } 127 128 private float getPerpendicularVelocity(VelocityTracker vt) { 129 return mSwipeDirection == X ? vt.getYVelocity() : 130 vt.getXVelocity(); 131 } 132 133 private void setTranslation(View v, float translate) { 134 if (mSwipeDirection == X) { 135 v.setTranslationX(translate); 136 } else { 137 v.setTranslationY(translate); 138 } 139 } 140 141 private float getSize(View v) { 142 return mSwipeDirection == X ? v.getMeasuredWidth() : 143 v.getMeasuredHeight(); 144 } 145 146 private float getAlphaForOffset(View view) { 147 float viewSize = getSize(view); 148 final float fadeSize = ALPHA_FADE_END * viewSize; 149 float result = 1.0f; 150 float pos = view.getTranslationX(); 151 if (pos >= viewSize * ALPHA_FADE_START) { 152 result = 1.0f - (pos - viewSize * ALPHA_FADE_START) / fadeSize; 153 } else if (pos < viewSize * (1.0f - ALPHA_FADE_START)) { 154 result = 1.0f + (viewSize * ALPHA_FADE_START + pos) / fadeSize; 155 } 156 float minAlpha = 0.5f; 157 return Math.max(minAlpha, result); 158 } 159 160 private float getTextAlphaForOffset(View view) { 161 float viewSize = getSize(view); 162 final float fadeSize = ALPHA_TEXT_FADE_START * viewSize; 163 float result = 1.0f; 164 float pos = view.getTranslationX(); 165 if (pos >= 0) { 166 result = 1.0f - pos / fadeSize; 167 } else if (pos < 0) { 168 result = 1.0f + pos / fadeSize; 169 } 170 return Math.max(0, result); 171 } 172 173 // invalidate the view's own bounds all the way up the view hierarchy 174 public static void invalidateGlobalRegion(View view) { 175 invalidateGlobalRegion( 176 view, 177 new RectF(view.getLeft(), view.getTop(), view.getRight(), view.getBottom())); 178 } 179 180 // invalidate a rectangle relative to the view's coordinate system all the way up the view 181 // hierarchy 182 public static void invalidateGlobalRegion(View view, RectF childBounds) { 183 //childBounds.offset(view.getTranslationX(), view.getTranslationY()); 184 if (DEBUG_INVALIDATE) 185 LogUtils.v(TAG, "-------------"); 186 while (view.getParent() != null && view.getParent() instanceof View) { 187 view = (View) view.getParent(); 188 view.getMatrix().mapRect(childBounds); 189 view.invalidate((int) Math.floor(childBounds.left), 190 (int) Math.floor(childBounds.top), 191 (int) Math.ceil(childBounds.right), 192 (int) Math.ceil(childBounds.bottom)); 193 if (DEBUG_INVALIDATE) { 194 LogUtils.v(TAG, "INVALIDATE(" + (int) Math.floor(childBounds.left) 195 + "," + (int) Math.floor(childBounds.top) 196 + "," + (int) Math.ceil(childBounds.right) 197 + "," + (int) Math.ceil(childBounds.bottom)); 198 } 199 } 200 } 201 202 public boolean onInterceptTouchEvent(MotionEvent ev) { 203 final int action = ev.getAction(); 204 switch (action) { 205 case MotionEvent.ACTION_DOWN: 206 mLastY = ev.getY(); 207 mDragging = false; 208 View view = mCallback.getChildAtPosition(ev); 209 if (view instanceof SwipeableItemView) { 210 mCurrView = (SwipeableItemView) view; 211 } 212 mVelocityTracker.clear(); 213 if (mCurrView != null) { 214 mCurrAnimView = mCurrView.getSwipeableView().getView(); 215 mCanCurrViewBeDimissed = mCallback.canChildBeDismissed(mCurrView); 216 mVelocityTracker.addMovement(ev); 217 mInitialTouchPosX = ev.getX(); 218 mInitialTouchPosY = ev.getY(); 219 } 220 mCallback.cancelDismissCounter(); 221 break; 222 case MotionEvent.ACTION_MOVE: 223 if (mCurrView != null) { 224 // Check the movement direction. 225 if (mLastY >= 0 && !mDragging) { 226 float currY = ev.getY(); 227 float currX = ev.getX(); 228 float deltaY = Math.abs(currY - mInitialTouchPosY); 229 float deltaX = Math.abs(currX - mInitialTouchPosX); 230 if (deltaY > mCurrView.getMinAllowScrollDistance() 231 && deltaY > (FACTOR * deltaX)) { 232 mLastY = ev.getY(); 233 mCallback.onScroll(); 234 return false; 235 } 236 } 237 mVelocityTracker.addMovement(ev); 238 float pos = ev.getX(); 239 float delta = pos - mInitialTouchPosX; 240 if (Math.abs(delta) > mPagingTouchSlop) { 241 mCallback.onBeginDrag(mCurrView.getSwipeableView().getView()); 242 mPrevView = mCallback.getLastSwipedItem(); 243 mDragging = true; 244 mInitialTouchPosX = ev.getX() - mCurrAnimView.getTranslationX(); 245 mInitialTouchPosY = ev.getY(); 246 } 247 } 248 mLastY = ev.getY(); 249 break; 250 case MotionEvent.ACTION_UP: 251 case MotionEvent.ACTION_CANCEL: 252 mDragging = false; 253 mCurrView = null; 254 mCurrAnimView = null; 255 mLastY = -1; 256 break; 257 } 258 return mDragging; 259 } 260 261 /** 262 * @param view The view to be dismissed 263 * @param velocity The desired pixels/second speed at which the view should 264 * move 265 */ 266 private void dismissChild(final SwipeableItemView view, float velocity) { 267 final View animView = view.getSwipeableView().getView(); 268 final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view); 269 float newPos = determinePos(animView, velocity); 270 int duration = determineDuration(animView, newPos, velocity); 271 272 Utils.enableHardwareLayer(animView); 273 ObjectAnimator anim = createDismissAnimation(animView, newPos, duration); 274 anim.addListener(new AnimatorListenerAdapter() { 275 @Override 276 public void onAnimationEnd(Animator animation) { 277 mCallback.onChildDismissed(view); 278 animView.setLayerType(View.LAYER_TYPE_NONE, null); 279 } 280 }); 281 anim.addUpdateListener(new AnimatorUpdateListener() { 282 @Override 283 public void onAnimationUpdate(ValueAnimator animation) { 284 if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { 285 animView.setAlpha(getAlphaForOffset(animView)); 286 } 287 invalidateGlobalRegion(animView); 288 } 289 }); 290 anim.start(); 291 } 292 293 private static int determineDuration(View animView, float newPos, float velocity) { 294 int duration = MAX_ESCAPE_ANIMATION_DURATION; 295 if (velocity != 0) { 296 duration = Math 297 .min(duration, 298 (int) (Math.abs(newPos - animView.getTranslationX()) * 1000f / Math 299 .abs(velocity))); 300 } else { 301 duration = DEFAULT_ESCAPE_ANIMATION_DURATION; 302 } 303 return duration; 304 } 305 306 private float determinePos(View animView, float velocity) { 307 final float newPos; 308 if (velocity < 0 || (velocity == 0 && animView.getTranslationX() < 0) 309 // if we use the Menu to dismiss an item in landscape, animate up 310 || (velocity == 0 && animView.getTranslationX() == 0 && mSwipeDirection == Y)) { 311 newPos = -getSize(animView); 312 } else { 313 newPos = getSize(animView); 314 } 315 return newPos; 316 } 317 318 public void snapChild(final SwipeableItemView view) { 319 final View animView = view.getSwipeableView().getView(); 320 final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view); 321 final ObjectAnimator anim = createTranslationAnimation(animView, 0); 322 final int duration = SNAP_ANIM_LEN; 323 anim.setDuration(duration); 324 anim.addUpdateListener(new AnimatorUpdateListener() { 325 @Override 326 public void onAnimationUpdate(ValueAnimator animation) { 327 if (FADE_OUT_DURING_SWIPE && canAnimViewBeDismissed) { 328 animView.setAlpha(getAlphaForOffset(animView)); 329 } 330 invalidateGlobalRegion(animView); 331 } 332 }); 333 anim.addListener(new Animator.AnimatorListener() { 334 @Override 335 public void onAnimationStart(Animator animation) { 336 } 337 @Override 338 public void onAnimationEnd(Animator animation) { 339 animView.setAlpha(1.0f); 340 mCallback.onDragCancelled(mCurrView); 341 } 342 @Override 343 public void onAnimationCancel(Animator animation) { 344 } 345 @Override 346 public void onAnimationRepeat(Animator animation) { 347 } 348 }); 349 anim.start(); 350 } 351 352 public boolean onTouchEvent(MotionEvent ev) { 353 if (!mDragging) { 354 return false; 355 } 356 mVelocityTracker.addMovement(ev); 357 final int action = ev.getAction(); 358 switch (action) { 359 case MotionEvent.ACTION_OUTSIDE: 360 case MotionEvent.ACTION_MOVE: 361 if (mCurrView != null) { 362 float deltaX = ev.getX() - mInitialTouchPosX; 363 // If the swipe started in the dead region, ignore it. 364 if (mInitialTouchPosX <= (DEAD_REGION_FOR_SWIPE * mDensityScale)){ 365 return true; 366 } 367 // If the user has gone vertical and not gone horizontalish AT 368 // LEAST minBeforeLock, switch to scroll. Otherwise, cancel 369 // the swipe. 370 float minDistance = MIN_SWIPE; 371 if (Math.abs(deltaX) < minDistance) { 372 // Don't start the drag until at least X distance has 373 // occurred. 374 return true; 375 } 376 // don't let items that can't be dismissed be dragged more 377 // than maxScrollDistance 378 if (CONSTRAIN_SWIPE && !mCallback.canChildBeDismissed(mCurrView)) { 379 float size = getSize(mCurrAnimView); 380 float maxScrollDistance = 0.15f * size; 381 if (Math.abs(deltaX) >= size) { 382 deltaX = deltaX > 0 ? maxScrollDistance : -maxScrollDistance; 383 } else { 384 deltaX = maxScrollDistance 385 * (float) Math.sin((deltaX / size) * (Math.PI / 2)); 386 } 387 } 388 setTranslation(mCurrAnimView, deltaX); 389 if (FADE_OUT_DURING_SWIPE && mCanCurrViewBeDimissed) { 390 mCurrAnimView.setAlpha(getAlphaForOffset(mCurrAnimView)); 391 if (mPrevView != null) { 392 // Base how much the text of the prev item is faded 393 // on how far the current item has moved. 394 mPrevView.setTextAlpha(getTextAlphaForOffset(mCurrAnimView)); 395 } 396 } 397 invalidateGlobalRegion(mCurrView.getSwipeableView().getView()); 398 } 399 break; 400 case MotionEvent.ACTION_UP: 401 case MotionEvent.ACTION_CANCEL: 402 if (mCurrView != null) { 403 float maxVelocity = MAX_DISMISS_VELOCITY * mDensityScale; 404 mVelocityTracker.computeCurrentVelocity(1000 /* px/sec */, maxVelocity); 405 float escapeVelocity = SWIPE_ESCAPE_VELOCITY * mDensityScale; 406 float velocity = getVelocity(mVelocityTracker); 407 float perpendicularVelocity = getPerpendicularVelocity(mVelocityTracker); 408 409 // Decide whether to dismiss the current view 410 // Tweak constants below as required to prevent erroneous 411 // swipe/dismiss 412 float translation = Math.abs(mCurrAnimView.getTranslationX()); 413 float currAnimViewSize = getSize(mCurrAnimView); 414 // Long swipe = translation of .4 * width 415 boolean childSwipedFarEnough = DISMISS_IF_SWIPED_FAR_ENOUGH 416 && translation > 0.4 * currAnimViewSize; 417 // Fast swipe = > escapeVelocity and translation of .1 * 418 // width 419 boolean childSwipedFastEnough = (Math.abs(velocity) > escapeVelocity) 420 && (Math.abs(velocity) > Math.abs(perpendicularVelocity)) 421 && (velocity > 0) == (mCurrAnimView.getTranslationX() > 0) 422 && translation > 0.05 * currAnimViewSize; 423 if (LOG_SWIPE_DISMISS_VELOCITY) { 424 LogUtils.v(TAG, "Swipe/Dismiss: " + velocity + "/" + escapeVelocity + "/" 425 + perpendicularVelocity + ", x: " + translation + "/" 426 + currAnimViewSize); 427 } 428 429 boolean dismissChild = mCallback.canChildBeDismissed(mCurrView) 430 && (childSwipedFastEnough || childSwipedFarEnough); 431 432 if (dismissChild) { 433 dismissChild(mCurrView, childSwipedFastEnough ? velocity : 0f); 434 } else { 435 snapChild(mCurrView); 436 } 437 } 438 break; 439 } 440 return true; 441 } 442 443 public interface Callback { 444 View getChildAtPosition(MotionEvent ev); 445 446 void cancelDismissCounter(); 447 448 void onScroll(); 449 450 boolean canChildBeDismissed(SwipeableItemView v); 451 452 void onBeginDrag(View v); 453 454 void onChildDismissed(SwipeableItemView v); 455 456 void onDragCancelled(SwipeableItemView v); 457 458 ConversationCheckedSet getCheckedSet(); 459 460 LeaveBehindItem getLastSwipedItem(); 461 } 462} 463