Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 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.content.Context; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 20 | import android.hardware.SensorManager; |
| 21 | import android.util.FloatMath; |
| 22 | import android.util.Log; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 23 | import android.view.ViewConfiguration; |
| 24 | import android.view.animation.AnimationUtils; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 25 | import android.view.animation.Interpolator; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 26 | |
| 27 | /** |
| 28 | * This class encapsulates scrolling with the ability to overshoot the bounds |
| 29 | * of a scrolling operation. This class is a drop-in replacement for |
| 30 | * {@link android.widget.Scroller} in most cases. |
| 31 | */ |
| 32 | public class OverScroller { |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 33 | private int mMode; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 34 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 35 | private final SplineOverScroller mScrollerX; |
| 36 | private final SplineOverScroller mScrollerY; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 37 | |
Adam Powell | 0b8acd8 | 2012-04-25 20:29:23 -0700 | [diff] [blame] | 38 | private Interpolator mInterpolator; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 39 | |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 40 | private final boolean mFlywheel; |
| 41 | |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 42 | private static final int DEFAULT_DURATION = 250; |
| 43 | private static final int SCROLL_MODE = 0; |
| 44 | private static final int FLING_MODE = 1; |
| 45 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 46 | /** |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 47 | * Creates an OverScroller with a viscous fluid scroll interpolator and flywheel. |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 48 | * @param context |
| 49 | */ |
| 50 | public OverScroller(Context context) { |
| 51 | this(context, null); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 52 | } |
| 53 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 54 | /** |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 55 | * Creates an OverScroller with flywheel enabled. |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 56 | * @param context The context of this application. |
| 57 | * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will |
| 58 | * be used. |
| 59 | */ |
| 60 | public OverScroller(Context context, Interpolator interpolator) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 61 | this(context, interpolator, true); |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Creates an OverScroller. |
| 66 | * @param context The context of this application. |
| 67 | * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will |
| 68 | * be used. |
| 69 | * @param flywheel If true, successive fling motions will keep on increasing scroll speed. |
Wink Saville | 086c061 | 2010-12-11 09:01:31 -0800 | [diff] [blame] | 70 | * @hide |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 71 | */ |
| 72 | public OverScroller(Context context, Interpolator interpolator, boolean flywheel) { |
Alan Viverette | 79a5fef | 2013-09-04 16:37:57 -0700 | [diff] [blame] | 73 | if (interpolator == null) { |
| 74 | mInterpolator = new Scroller.ViscousFluidInterpolator(); |
| 75 | } else { |
| 76 | mInterpolator = interpolator; |
| 77 | } |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 78 | mFlywheel = flywheel; |
Adam Powell | 990dfc6f | 2012-08-09 16:45:59 -0700 | [diff] [blame] | 79 | mScrollerX = new SplineOverScroller(context); |
| 80 | mScrollerY = new SplineOverScroller(context); |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Creates an OverScroller with flywheel enabled. |
| 85 | * @param context The context of this application. |
| 86 | * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will |
| 87 | * be used. |
| 88 | * @param bounceCoefficientX A value between 0 and 1 that will determine the proportion of the |
| 89 | * velocity which is preserved in the bounce when the horizontal edge is reached. A null value |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 90 | * means no bounce. This behavior is no longer supported and this coefficient has no effect. |
| 91 | * @param bounceCoefficientY Same as bounceCoefficientX but for the vertical direction. This |
| 92 | * behavior is no longer supported and this coefficient has no effect. |
Wink Saville | 086c061 | 2010-12-11 09:01:31 -0800 | [diff] [blame] | 93 | * !deprecated Use {!link #OverScroller(Context, Interpolator, boolean)} instead. |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 94 | */ |
| 95 | public OverScroller(Context context, Interpolator interpolator, |
| 96 | float bounceCoefficientX, float bounceCoefficientY) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 97 | this(context, interpolator, true); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Creates an OverScroller. |
| 102 | * @param context The context of this application. |
| 103 | * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will |
| 104 | * be used. |
| 105 | * @param bounceCoefficientX A value between 0 and 1 that will determine the proportion of the |
| 106 | * velocity which is preserved in the bounce when the horizontal edge is reached. A null value |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 107 | * means no bounce. This behavior is no longer supported and this coefficient has no effect. |
| 108 | * @param bounceCoefficientY Same as bounceCoefficientX but for the vertical direction. This |
| 109 | * behavior is no longer supported and this coefficient has no effect. |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 110 | * @param flywheel If true, successive fling motions will keep on increasing scroll speed. |
Wink Saville | 086c061 | 2010-12-11 09:01:31 -0800 | [diff] [blame] | 111 | * !deprecated Use {!link OverScroller(Context, Interpolator, boolean)} instead. |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 112 | */ |
| 113 | public OverScroller(Context context, Interpolator interpolator, |
| 114 | float bounceCoefficientX, float bounceCoefficientY, boolean flywheel) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 115 | this(context, interpolator, flywheel); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 116 | } |
| 117 | |
Adam Powell | 0b8acd8 | 2012-04-25 20:29:23 -0700 | [diff] [blame] | 118 | void setInterpolator(Interpolator interpolator) { |
Alan Viverette | 79a5fef | 2013-09-04 16:37:57 -0700 | [diff] [blame] | 119 | if (interpolator == null) { |
| 120 | mInterpolator = new Scroller.ViscousFluidInterpolator(); |
| 121 | } else { |
| 122 | mInterpolator = interpolator; |
| 123 | } |
Adam Powell | 0b8acd8 | 2012-04-25 20:29:23 -0700 | [diff] [blame] | 124 | } |
| 125 | |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 126 | /** |
| 127 | * The amount of friction applied to flings. The default value |
| 128 | * is {@link ViewConfiguration#getScrollFriction}. |
| 129 | * |
| 130 | * @param friction A scalar dimension-less value representing the coefficient of |
| 131 | * friction. |
| 132 | */ |
| 133 | public final void setFriction(float friction) { |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 134 | mScrollerX.setFriction(friction); |
| 135 | mScrollerY.setFriction(friction); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 136 | } |
| 137 | |
| 138 | /** |
| 139 | * |
| 140 | * Returns whether the scroller has finished scrolling. |
| 141 | * |
| 142 | * @return True if the scroller has finished scrolling, false otherwise. |
| 143 | */ |
| 144 | public final boolean isFinished() { |
| 145 | return mScrollerX.mFinished && mScrollerY.mFinished; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Force the finished field to a particular value. Contrary to |
| 150 | * {@link #abortAnimation()}, forcing the animation to finished |
| 151 | * does NOT cause the scroller to move to the final x and y |
| 152 | * position. |
| 153 | * |
| 154 | * @param finished The new finished value. |
| 155 | */ |
| 156 | public final void forceFinished(boolean finished) { |
| 157 | mScrollerX.mFinished = mScrollerY.mFinished = finished; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Returns the current X offset in the scroll. |
| 162 | * |
| 163 | * @return The new X offset as an absolute distance from the origin. |
| 164 | */ |
| 165 | public final int getCurrX() { |
| 166 | return mScrollerX.mCurrentPosition; |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * Returns the current Y offset in the scroll. |
| 171 | * |
| 172 | * @return The new Y offset as an absolute distance from the origin. |
| 173 | */ |
| 174 | public final int getCurrY() { |
| 175 | return mScrollerY.mCurrentPosition; |
| 176 | } |
| 177 | |
| 178 | /** |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 179 | * Returns the absolute value of the current velocity. |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 180 | * |
| 181 | * @return The original velocity less the deceleration, norm of the X and Y velocity vector. |
| 182 | */ |
| 183 | public float getCurrVelocity() { |
| 184 | float squaredNorm = mScrollerX.mCurrVelocity * mScrollerX.mCurrVelocity; |
| 185 | squaredNorm += mScrollerY.mCurrVelocity * mScrollerY.mCurrVelocity; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 186 | return FloatMath.sqrt(squaredNorm); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 187 | } |
| 188 | |
| 189 | /** |
| 190 | * Returns the start X offset in the scroll. |
| 191 | * |
| 192 | * @return The start X offset as an absolute distance from the origin. |
| 193 | */ |
| 194 | public final int getStartX() { |
| 195 | return mScrollerX.mStart; |
| 196 | } |
| 197 | |
| 198 | /** |
| 199 | * Returns the start Y offset in the scroll. |
| 200 | * |
| 201 | * @return The start Y offset as an absolute distance from the origin. |
| 202 | */ |
| 203 | public final int getStartY() { |
| 204 | return mScrollerY.mStart; |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Returns where the scroll will end. Valid only for "fling" scrolls. |
| 209 | * |
| 210 | * @return The final X offset as an absolute distance from the origin. |
| 211 | */ |
| 212 | public final int getFinalX() { |
| 213 | return mScrollerX.mFinal; |
| 214 | } |
| 215 | |
| 216 | /** |
| 217 | * Returns where the scroll will end. Valid only for "fling" scrolls. |
| 218 | * |
| 219 | * @return The final Y offset as an absolute distance from the origin. |
| 220 | */ |
| 221 | public final int getFinalY() { |
| 222 | return mScrollerY.mFinal; |
| 223 | } |
| 224 | |
| 225 | /** |
| 226 | * Returns how long the scroll event will take, in milliseconds. |
| 227 | * |
| 228 | * @return The duration of the scroll in milliseconds. |
| 229 | * |
| 230 | * @hide Pending removal once nothing depends on it |
| 231 | * @deprecated OverScrollers don't necessarily have a fixed duration. |
| 232 | * This function will lie to the best of its ability. |
| 233 | */ |
| 234 | @Deprecated |
| 235 | public final int getDuration() { |
| 236 | return Math.max(mScrollerX.mDuration, mScrollerY.mDuration); |
| 237 | } |
| 238 | |
| 239 | /** |
| 240 | * Extend the scroll animation. This allows a running animation to scroll |
| 241 | * further and longer, when used with {@link #setFinalX(int)} or {@link #setFinalY(int)}. |
| 242 | * |
| 243 | * @param extend Additional time to scroll in milliseconds. |
| 244 | * @see #setFinalX(int) |
| 245 | * @see #setFinalY(int) |
| 246 | * |
| 247 | * @hide Pending removal once nothing depends on it |
| 248 | * @deprecated OverScrollers don't necessarily have a fixed duration. |
| 249 | * Instead of setting a new final position and extending |
| 250 | * the duration of an existing scroll, use startScroll |
| 251 | * to begin a new animation. |
| 252 | */ |
| 253 | @Deprecated |
| 254 | public void extendDuration(int extend) { |
| 255 | mScrollerX.extendDuration(extend); |
| 256 | mScrollerY.extendDuration(extend); |
| 257 | } |
| 258 | |
| 259 | /** |
| 260 | * Sets the final position (X) for this scroller. |
| 261 | * |
| 262 | * @param newX The new X offset as an absolute distance from the origin. |
| 263 | * @see #extendDuration(int) |
| 264 | * @see #setFinalY(int) |
| 265 | * |
| 266 | * @hide Pending removal once nothing depends on it |
| 267 | * @deprecated OverScroller's final position may change during an animation. |
| 268 | * Instead of setting a new final position and extending |
| 269 | * the duration of an existing scroll, use startScroll |
| 270 | * to begin a new animation. |
| 271 | */ |
| 272 | @Deprecated |
| 273 | public void setFinalX(int newX) { |
| 274 | mScrollerX.setFinalPosition(newX); |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Sets the final position (Y) for this scroller. |
| 279 | * |
| 280 | * @param newY The new Y offset as an absolute distance from the origin. |
| 281 | * @see #extendDuration(int) |
| 282 | * @see #setFinalX(int) |
| 283 | * |
| 284 | * @hide Pending removal once nothing depends on it |
| 285 | * @deprecated OverScroller's final position may change during an animation. |
| 286 | * Instead of setting a new final position and extending |
| 287 | * the duration of an existing scroll, use startScroll |
| 288 | * to begin a new animation. |
| 289 | */ |
| 290 | @Deprecated |
| 291 | public void setFinalY(int newY) { |
| 292 | mScrollerY.setFinalPosition(newY); |
| 293 | } |
| 294 | |
| 295 | /** |
| 296 | * Call this when you want to know the new location. If it returns true, the |
| 297 | * animation is not yet finished. |
| 298 | */ |
| 299 | public boolean computeScrollOffset() { |
| 300 | if (isFinished()) { |
| 301 | return false; |
| 302 | } |
| 303 | |
| 304 | switch (mMode) { |
| 305 | case SCROLL_MODE: |
| 306 | long time = AnimationUtils.currentAnimationTimeMillis(); |
| 307 | // Any scroller can be used for time, since they were started |
| 308 | // together in scroll mode. We use X here. |
| 309 | final long elapsedTime = time - mScrollerX.mStartTime; |
| 310 | |
| 311 | final int duration = mScrollerX.mDuration; |
| 312 | if (elapsedTime < duration) { |
Alan Viverette | 79a5fef | 2013-09-04 16:37:57 -0700 | [diff] [blame] | 313 | final float q = mInterpolator.getInterpolation(elapsedTime / (float) duration); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 314 | mScrollerX.updateScroll(q); |
| 315 | mScrollerY.updateScroll(q); |
| 316 | } else { |
| 317 | abortAnimation(); |
| 318 | } |
| 319 | break; |
| 320 | |
| 321 | case FLING_MODE: |
| 322 | if (!mScrollerX.mFinished) { |
| 323 | if (!mScrollerX.update()) { |
| 324 | if (!mScrollerX.continueWhenFinished()) { |
| 325 | mScrollerX.finish(); |
| 326 | } |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | if (!mScrollerY.mFinished) { |
| 331 | if (!mScrollerY.update()) { |
| 332 | if (!mScrollerY.continueWhenFinished()) { |
| 333 | mScrollerY.finish(); |
| 334 | } |
| 335 | } |
| 336 | } |
| 337 | |
| 338 | break; |
| 339 | } |
| 340 | |
| 341 | return true; |
| 342 | } |
| 343 | |
| 344 | /** |
| 345 | * Start scrolling by providing a starting point and the distance to travel. |
| 346 | * The scroll will use the default value of 250 milliseconds for the |
| 347 | * duration. |
| 348 | * |
| 349 | * @param startX Starting horizontal scroll offset in pixels. Positive |
| 350 | * numbers will scroll the content to the left. |
| 351 | * @param startY Starting vertical scroll offset in pixels. Positive numbers |
| 352 | * will scroll the content up. |
| 353 | * @param dx Horizontal distance to travel. Positive numbers will scroll the |
| 354 | * content to the left. |
| 355 | * @param dy Vertical distance to travel. Positive numbers will scroll the |
| 356 | * content up. |
| 357 | */ |
| 358 | public void startScroll(int startX, int startY, int dx, int dy) { |
| 359 | startScroll(startX, startY, dx, dy, DEFAULT_DURATION); |
| 360 | } |
| 361 | |
| 362 | /** |
| 363 | * Start scrolling by providing a starting point and the distance to travel. |
| 364 | * |
| 365 | * @param startX Starting horizontal scroll offset in pixels. Positive |
| 366 | * numbers will scroll the content to the left. |
| 367 | * @param startY Starting vertical scroll offset in pixels. Positive numbers |
| 368 | * will scroll the content up. |
| 369 | * @param dx Horizontal distance to travel. Positive numbers will scroll the |
| 370 | * content to the left. |
| 371 | * @param dy Vertical distance to travel. Positive numbers will scroll the |
| 372 | * content up. |
| 373 | * @param duration Duration of the scroll in milliseconds. |
| 374 | */ |
| 375 | public void startScroll(int startX, int startY, int dx, int dy, int duration) { |
| 376 | mMode = SCROLL_MODE; |
| 377 | mScrollerX.startScroll(startX, dx, duration); |
| 378 | mScrollerY.startScroll(startY, dy, duration); |
| 379 | } |
| 380 | |
| 381 | /** |
| 382 | * Call this when you want to 'spring back' into a valid coordinate range. |
| 383 | * |
| 384 | * @param startX Starting X coordinate |
| 385 | * @param startY Starting Y coordinate |
| 386 | * @param minX Minimum valid X value |
| 387 | * @param maxX Maximum valid X value |
| 388 | * @param minY Minimum valid Y value |
| 389 | * @param maxY Minimum valid Y value |
| 390 | * @return true if a springback was initiated, false if startX and startY were |
| 391 | * already within the valid range. |
| 392 | */ |
| 393 | public boolean springBack(int startX, int startY, int minX, int maxX, int minY, int maxY) { |
| 394 | mMode = FLING_MODE; |
| 395 | |
| 396 | // Make sure both methods are called. |
| 397 | final boolean spingbackX = mScrollerX.springback(startX, minX, maxX); |
| 398 | final boolean spingbackY = mScrollerY.springback(startY, minY, maxY); |
| 399 | return spingbackX || spingbackY; |
| 400 | } |
| 401 | |
| 402 | public void fling(int startX, int startY, int velocityX, int velocityY, |
| 403 | int minX, int maxX, int minY, int maxY) { |
| 404 | fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, 0, 0); |
| 405 | } |
| 406 | |
| 407 | /** |
| 408 | * Start scrolling based on a fling gesture. The distance traveled will |
| 409 | * depend on the initial velocity of the fling. |
| 410 | * |
| 411 | * @param startX Starting point of the scroll (X) |
| 412 | * @param startY Starting point of the scroll (Y) |
| 413 | * @param velocityX Initial velocity of the fling (X) measured in pixels per |
| 414 | * second. |
| 415 | * @param velocityY Initial velocity of the fling (Y) measured in pixels per |
| 416 | * second |
| 417 | * @param minX Minimum X value. The scroller will not scroll past this point |
| 418 | * unless overX > 0. If overfling is allowed, it will use minX as |
| 419 | * a springback boundary. |
| 420 | * @param maxX Maximum X value. The scroller will not scroll past this point |
| 421 | * unless overX > 0. If overfling is allowed, it will use maxX as |
| 422 | * a springback boundary. |
| 423 | * @param minY Minimum Y value. The scroller will not scroll past this point |
| 424 | * unless overY > 0. If overfling is allowed, it will use minY as |
| 425 | * a springback boundary. |
| 426 | * @param maxY Maximum Y value. The scroller will not scroll past this point |
| 427 | * unless overY > 0. If overfling is allowed, it will use maxY as |
| 428 | * a springback boundary. |
| 429 | * @param overX Overfling range. If > 0, horizontal overfling in either |
| 430 | * direction will be possible. |
| 431 | * @param overY Overfling range. If > 0, vertical overfling in either |
| 432 | * direction will be possible. |
| 433 | */ |
| 434 | public void fling(int startX, int startY, int velocityX, int velocityY, |
| 435 | int minX, int maxX, int minY, int maxY, int overX, int overY) { |
| 436 | // Continue a scroll or fling in progress |
| 437 | if (mFlywheel && !isFinished()) { |
| 438 | float oldVelocityX = mScrollerX.mCurrVelocity; |
| 439 | float oldVelocityY = mScrollerY.mCurrVelocity; |
| 440 | if (Math.signum(velocityX) == Math.signum(oldVelocityX) && |
| 441 | Math.signum(velocityY) == Math.signum(oldVelocityY)) { |
| 442 | velocityX += oldVelocityX; |
| 443 | velocityY += oldVelocityY; |
| 444 | } |
| 445 | } |
| 446 | |
| 447 | mMode = FLING_MODE; |
| 448 | mScrollerX.fling(startX, velocityX, minX, maxX, overX); |
| 449 | mScrollerY.fling(startY, velocityY, minY, maxY, overY); |
| 450 | } |
| 451 | |
| 452 | /** |
| 453 | * Notify the scroller that we've reached a horizontal boundary. |
| 454 | * Normally the information to handle this will already be known |
| 455 | * when the animation is started, such as in a call to one of the |
| 456 | * fling functions. However there are cases where this cannot be known |
| 457 | * in advance. This function will transition the current motion and |
| 458 | * animate from startX to finalX as appropriate. |
| 459 | * |
| 460 | * @param startX Starting/current X position |
| 461 | * @param finalX Desired final X position |
| 462 | * @param overX Magnitude of overscroll allowed. This should be the maximum |
| 463 | * desired distance from finalX. Absolute value - must be positive. |
| 464 | */ |
| 465 | public void notifyHorizontalEdgeReached(int startX, int finalX, int overX) { |
| 466 | mScrollerX.notifyEdgeReached(startX, finalX, overX); |
| 467 | } |
| 468 | |
| 469 | /** |
| 470 | * Notify the scroller that we've reached a vertical boundary. |
| 471 | * Normally the information to handle this will already be known |
| 472 | * when the animation is started, such as in a call to one of the |
| 473 | * fling functions. However there are cases where this cannot be known |
| 474 | * in advance. This function will animate a parabolic motion from |
| 475 | * startY to finalY. |
| 476 | * |
| 477 | * @param startY Starting/current Y position |
| 478 | * @param finalY Desired final Y position |
| 479 | * @param overY Magnitude of overscroll allowed. This should be the maximum |
| 480 | * desired distance from finalY. Absolute value - must be positive. |
| 481 | */ |
| 482 | public void notifyVerticalEdgeReached(int startY, int finalY, int overY) { |
| 483 | mScrollerY.notifyEdgeReached(startY, finalY, overY); |
| 484 | } |
| 485 | |
| 486 | /** |
| 487 | * Returns whether the current Scroller is currently returning to a valid position. |
| 488 | * Valid bounds were provided by the |
| 489 | * {@link #fling(int, int, int, int, int, int, int, int, int, int)} method. |
| 490 | * |
| 491 | * One should check this value before calling |
| 492 | * {@link #startScroll(int, int, int, int)} as the interpolation currently in progress |
| 493 | * to restore a valid position will then be stopped. The caller has to take into account |
| 494 | * the fact that the started scroll will start from an overscrolled position. |
| 495 | * |
| 496 | * @return true when the current position is overscrolled and in the process of |
| 497 | * interpolating back to a valid value. |
| 498 | */ |
| 499 | public boolean isOverScrolled() { |
| 500 | return ((!mScrollerX.mFinished && |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 501 | mScrollerX.mState != SplineOverScroller.SPLINE) || |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 502 | (!mScrollerY.mFinished && |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 503 | mScrollerY.mState != SplineOverScroller.SPLINE)); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 504 | } |
| 505 | |
| 506 | /** |
| 507 | * Stops the animation. Contrary to {@link #forceFinished(boolean)}, |
| 508 | * aborting the animating causes the scroller to move to the final x and y |
| 509 | * positions. |
| 510 | * |
| 511 | * @see #forceFinished(boolean) |
| 512 | */ |
| 513 | public void abortAnimation() { |
| 514 | mScrollerX.finish(); |
| 515 | mScrollerY.finish(); |
| 516 | } |
| 517 | |
| 518 | /** |
| 519 | * Returns the time elapsed since the beginning of the scrolling. |
| 520 | * |
| 521 | * @return The elapsed time in milliseconds. |
| 522 | * |
| 523 | * @hide |
| 524 | */ |
| 525 | public int timePassed() { |
| 526 | final long time = AnimationUtils.currentAnimationTimeMillis(); |
| 527 | final long startTime = Math.min(mScrollerX.mStartTime, mScrollerY.mStartTime); |
| 528 | return (int) (time - startTime); |
| 529 | } |
| 530 | |
| 531 | /** |
| 532 | * @hide |
| 533 | */ |
| 534 | public boolean isScrollingInDirection(float xvel, float yvel) { |
| 535 | final int dx = mScrollerX.mFinal - mScrollerX.mStart; |
| 536 | final int dy = mScrollerY.mFinal - mScrollerY.mStart; |
| 537 | return !isFinished() && Math.signum(xvel) == Math.signum(dx) && |
Jeff Brown | b0c71eb | 2011-09-16 21:40:49 -0700 | [diff] [blame] | 538 | Math.signum(yvel) == Math.signum(dy); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 539 | } |
| 540 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 541 | static class SplineOverScroller { |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 542 | // Initial position |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 543 | private int mStart; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 544 | |
| 545 | // Current position |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 546 | private int mCurrentPosition; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 547 | |
| 548 | // Final position |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 549 | private int mFinal; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 550 | |
| 551 | // Initial velocity |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 552 | private int mVelocity; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 553 | |
| 554 | // Current velocity |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 555 | private float mCurrVelocity; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 556 | |
| 557 | // Constant current deceleration |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 558 | private float mDeceleration; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 559 | |
| 560 | // Animation starting time, in system milliseconds |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 561 | private long mStartTime; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 562 | |
| 563 | // Animation duration, in milliseconds |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 564 | private int mDuration; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 565 | |
| 566 | // Duration to complete spline component of animation |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 567 | private int mSplineDuration; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 568 | |
| 569 | // Distance to travel along spline animation |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 570 | private int mSplineDistance; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 571 | |
| 572 | // Whether the animation is currently in progress |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 573 | private boolean mFinished; |
| 574 | |
| 575 | // The allowed overshot distance before boundary is reached. |
| 576 | private int mOver; |
| 577 | |
| 578 | // Fling friction |
| 579 | private float mFlingFriction = ViewConfiguration.getScrollFriction(); |
| 580 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 581 | // Current state of the animation. |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 582 | private int mState = SPLINE; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 583 | |
| 584 | // Constant gravity value, used in the deceleration phase. |
| 585 | private static final float GRAVITY = 2000.0f; |
| 586 | |
Adam Powell | 990dfc6f | 2012-08-09 16:45:59 -0700 | [diff] [blame] | 587 | // A context-specific coefficient adjusted to physical values. |
| 588 | private float mPhysicalCoeff; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 589 | |
Justin Ho | a181bb4 | 2011-09-19 17:52:06 -0700 | [diff] [blame] | 590 | private static float DECELERATION_RATE = (float) (Math.log(0.78) / Math.log(0.9)); |
| 591 | private static final float INFLEXION = 0.35f; // Tension lines cross at (INFLEXION, 1) |
| 592 | private static final float START_TENSION = 0.5f; |
| 593 | private static final float END_TENSION = 1.0f; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 594 | private static final float P1 = START_TENSION * INFLEXION; |
| 595 | private static final float P2 = 1.0f - END_TENSION * (1.0f - INFLEXION); |
| 596 | |
| 597 | private static final int NB_SAMPLES = 100; |
| 598 | private static final float[] SPLINE_POSITION = new float[NB_SAMPLES + 1]; |
| 599 | private static final float[] SPLINE_TIME = new float[NB_SAMPLES + 1]; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 600 | |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 601 | private static final int SPLINE = 0; |
| 602 | private static final int CUBIC = 1; |
| 603 | private static final int BALLISTIC = 2; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 604 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 605 | static { |
| 606 | float x_min = 0.0f; |
| 607 | float y_min = 0.0f; |
| 608 | for (int i = 0; i < NB_SAMPLES; i++) { |
| 609 | final float alpha = (float) i / NB_SAMPLES; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 610 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 611 | float x_max = 1.0f; |
| 612 | float x, tx, coef; |
| 613 | while (true) { |
| 614 | x = x_min + (x_max - x_min) / 2.0f; |
| 615 | coef = 3.0f * x * (1.0f - x); |
| 616 | tx = coef * ((1.0f - x) * P1 + x * P2) + x * x * x; |
| 617 | if (Math.abs(tx - alpha) < 1E-5) break; |
| 618 | if (tx > alpha) x_max = x; |
| 619 | else x_min = x; |
| 620 | } |
| 621 | SPLINE_POSITION[i] = coef * ((1.0f - x) * START_TENSION + x) + x * x * x; |
| 622 | |
| 623 | float y_max = 1.0f; |
| 624 | float y, dy; |
| 625 | while (true) { |
| 626 | y = y_min + (y_max - y_min) / 2.0f; |
| 627 | coef = 3.0f * y * (1.0f - y); |
| 628 | dy = coef * ((1.0f - y) * START_TENSION + y) + y * y * y; |
| 629 | if (Math.abs(dy - alpha) < 1E-5) break; |
| 630 | if (dy > alpha) y_max = y; |
| 631 | else y_min = y; |
| 632 | } |
| 633 | SPLINE_TIME[i] = coef * ((1.0f - y) * P1 + y * P2) + y * y * y; |
| 634 | } |
| 635 | SPLINE_POSITION[NB_SAMPLES] = SPLINE_TIME[NB_SAMPLES] = 1.0f; |
| 636 | } |
| 637 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 638 | void setFriction(float friction) { |
| 639 | mFlingFriction = friction; |
| 640 | } |
| 641 | |
Adam Powell | 990dfc6f | 2012-08-09 16:45:59 -0700 | [diff] [blame] | 642 | SplineOverScroller(Context context) { |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 643 | mFinished = true; |
Adam Powell | 990dfc6f | 2012-08-09 16:45:59 -0700 | [diff] [blame] | 644 | final float ppi = context.getResources().getDisplayMetrics().density * 160.0f; |
| 645 | mPhysicalCoeff = SensorManager.GRAVITY_EARTH // g (m/s^2) |
| 646 | * 39.37f // inch/meter |
| 647 | * ppi |
| 648 | * 0.84f; // look and feel tuning |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 649 | } |
| 650 | |
| 651 | void updateScroll(float q) { |
| 652 | mCurrentPosition = mStart + Math.round(q * (mFinal - mStart)); |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * Get a signed deceleration that will reduce the velocity. |
| 657 | */ |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 658 | static private float getDeceleration(int velocity) { |
| 659 | return velocity > 0 ? -GRAVITY : GRAVITY; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 660 | } |
| 661 | |
| 662 | /* |
| 663 | * Modifies mDuration to the duration it takes to get from start to newFinal using the |
| 664 | * spline interpolation. The previous duration was needed to get to oldFinal. |
| 665 | */ |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 666 | private void adjustDuration(int start, int oldFinal, int newFinal) { |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 667 | final int oldDistance = oldFinal - start; |
| 668 | final int newDistance = newFinal - start; |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 669 | final float x = Math.abs((float) newDistance / oldDistance); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 670 | final int index = (int) (NB_SAMPLES * x); |
| 671 | if (index < NB_SAMPLES) { |
| 672 | final float x_inf = (float) index / NB_SAMPLES; |
| 673 | final float x_sup = (float) (index + 1) / NB_SAMPLES; |
| 674 | final float t_inf = SPLINE_TIME[index]; |
| 675 | final float t_sup = SPLINE_TIME[index + 1]; |
| 676 | final float timeCoef = t_inf + (x - x_inf) / (x_sup - x_inf) * (t_sup - t_inf); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 677 | mDuration *= timeCoef; |
| 678 | } |
| 679 | } |
| 680 | |
| 681 | void startScroll(int start, int distance, int duration) { |
| 682 | mFinished = false; |
| 683 | |
| 684 | mStart = start; |
| 685 | mFinal = start + distance; |
| 686 | |
| 687 | mStartTime = AnimationUtils.currentAnimationTimeMillis(); |
| 688 | mDuration = duration; |
| 689 | |
| 690 | // Unused |
| 691 | mDeceleration = 0.0f; |
| 692 | mVelocity = 0; |
| 693 | } |
| 694 | |
| 695 | void finish() { |
| 696 | mCurrentPosition = mFinal; |
| 697 | // Not reset since WebView relies on this value for fast fling. |
| 698 | // TODO: restore when WebView uses the fast fling implemented in this class. |
| 699 | // mCurrVelocity = 0.0f; |
| 700 | mFinished = true; |
| 701 | } |
| 702 | |
| 703 | void setFinalPosition(int position) { |
| 704 | mFinal = position; |
| 705 | mFinished = false; |
| 706 | } |
| 707 | |
| 708 | void extendDuration(int extend) { |
| 709 | final long time = AnimationUtils.currentAnimationTimeMillis(); |
| 710 | final int elapsedTime = (int) (time - mStartTime); |
| 711 | mDuration = elapsedTime + extend; |
| 712 | mFinished = false; |
| 713 | } |
| 714 | |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 715 | boolean springback(int start, int min, int max) { |
| 716 | mFinished = true; |
| 717 | |
| 718 | mStart = mFinal = start; |
| 719 | mVelocity = 0; |
| 720 | |
| 721 | mStartTime = AnimationUtils.currentAnimationTimeMillis(); |
| 722 | mDuration = 0; |
| 723 | |
| 724 | if (start < min) { |
| 725 | startSpringback(start, min, 0); |
| 726 | } else if (start > max) { |
| 727 | startSpringback(start, max, 0); |
| 728 | } |
| 729 | |
| 730 | return !mFinished; |
| 731 | } |
| 732 | |
| 733 | private void startSpringback(int start, int end, int velocity) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 734 | // mStartTime has been set |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 735 | mFinished = false; |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 736 | mState = CUBIC; |
| 737 | mStart = start; |
| 738 | mFinal = end; |
| 739 | final int delta = start - end; |
| 740 | mDeceleration = getDeceleration(delta); |
| 741 | // TODO take velocity into account |
| 742 | mVelocity = -delta; // only sign is used |
| 743 | mOver = Math.abs(delta); |
| 744 | mDuration = (int) (1000.0 * Math.sqrt(-2.0 * delta / mDeceleration)); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 745 | } |
| 746 | |
| 747 | void fling(int start, int velocity, int min, int max, int over) { |
| 748 | mOver = over; |
| 749 | mFinished = false; |
| 750 | mCurrVelocity = mVelocity = velocity; |
| 751 | mDuration = mSplineDuration = 0; |
| 752 | mStartTime = AnimationUtils.currentAnimationTimeMillis(); |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 753 | mCurrentPosition = mStart = start; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 754 | |
| 755 | if (start > max || start < min) { |
| 756 | startAfterEdge(start, min, max, velocity); |
| 757 | return; |
| 758 | } |
| 759 | |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 760 | mState = SPLINE; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 761 | double totalDistance = 0.0; |
| 762 | |
| 763 | if (velocity != 0) { |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 764 | mDuration = mSplineDuration = getSplineFlingDuration(velocity); |
| 765 | totalDistance = getSplineFlingDistance(velocity); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 766 | } |
| 767 | |
| 768 | mSplineDistance = (int) (totalDistance * Math.signum(velocity)); |
| 769 | mFinal = start + mSplineDistance; |
| 770 | |
| 771 | // Clamp to a valid final position |
| 772 | if (mFinal < min) { |
| 773 | adjustDuration(mStart, mFinal, min); |
| 774 | mFinal = min; |
| 775 | } |
| 776 | |
| 777 | if (mFinal > max) { |
| 778 | adjustDuration(mStart, mFinal, max); |
| 779 | mFinal = max; |
| 780 | } |
| 781 | } |
| 782 | |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 783 | private double getSplineDeceleration(int velocity) { |
Adam Powell | 990dfc6f | 2012-08-09 16:45:59 -0700 | [diff] [blame] | 784 | return Math.log(INFLEXION * Math.abs(velocity) / (mFlingFriction * mPhysicalCoeff)); |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 785 | } |
| 786 | |
| 787 | private double getSplineFlingDistance(int velocity) { |
| 788 | final double l = getSplineDeceleration(velocity); |
| 789 | final double decelMinusOne = DECELERATION_RATE - 1.0; |
Adam Powell | 990dfc6f | 2012-08-09 16:45:59 -0700 | [diff] [blame] | 790 | return mFlingFriction * mPhysicalCoeff * Math.exp(DECELERATION_RATE / decelMinusOne * l); |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 791 | } |
| 792 | |
| 793 | /* Returns the duration, expressed in milliseconds */ |
| 794 | private int getSplineFlingDuration(int velocity) { |
| 795 | final double l = getSplineDeceleration(velocity); |
| 796 | final double decelMinusOne = DECELERATION_RATE - 1.0; |
| 797 | return (int) (1000.0 * Math.exp(l / decelMinusOne)); |
| 798 | } |
| 799 | |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 800 | private void fitOnBounceCurve(int start, int end, int velocity) { |
| 801 | // Simulate a bounce that started from edge |
| 802 | final float durationToApex = - velocity / mDeceleration; |
| 803 | final float distanceToApex = velocity * velocity / 2.0f / Math.abs(mDeceleration); |
| 804 | final float distanceToEdge = Math.abs(end - start); |
| 805 | final float totalDuration = (float) Math.sqrt( |
| 806 | 2.0 * (distanceToApex + distanceToEdge) / Math.abs(mDeceleration)); |
| 807 | mStartTime -= (int) (1000.0f * (totalDuration - durationToApex)); |
| 808 | mStart = end; |
| 809 | mVelocity = (int) (- mDeceleration * totalDuration); |
| 810 | } |
| 811 | |
| 812 | private void startBounceAfterEdge(int start, int end, int velocity) { |
| 813 | mDeceleration = getDeceleration(velocity == 0 ? start - end : velocity); |
| 814 | fitOnBounceCurve(start, end, velocity); |
| 815 | onEdgeReached(); |
| 816 | } |
| 817 | |
| 818 | private void startAfterEdge(int start, int min, int max, int velocity) { |
| 819 | if (start > min && start < max) { |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 820 | Log.e("OverScroller", "startAfterEdge called from a valid position"); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 821 | mFinished = true; |
| 822 | return; |
| 823 | } |
| 824 | final boolean positive = start > max; |
| 825 | final int edge = positive ? max : min; |
| 826 | final int overDistance = start - edge; |
| 827 | boolean keepIncreasing = overDistance * velocity >= 0; |
| 828 | if (keepIncreasing) { |
| 829 | // Will result in a bounce or a to_boundary depending on velocity. |
| 830 | startBounceAfterEdge(start, edge, velocity); |
| 831 | } else { |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 832 | final double totalDistance = getSplineFlingDistance(velocity); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 833 | if (totalDistance > Math.abs(overDistance)) { |
| 834 | fling(start, velocity, positive ? min : start, positive ? start : max, mOver); |
| 835 | } else { |
| 836 | startSpringback(start, edge, velocity); |
| 837 | } |
| 838 | } |
| 839 | } |
| 840 | |
| 841 | void notifyEdgeReached(int start, int end, int over) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 842 | // mState is used to detect successive notifications |
| 843 | if (mState == SPLINE) { |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 844 | mOver = over; |
| 845 | mStartTime = AnimationUtils.currentAnimationTimeMillis(); |
| 846 | // We were in fling/scroll mode before: current velocity is such that distance to |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 847 | // edge is increasing. This ensures that startAfterEdge will not start a new fling. |
Gilles Debunne | fff4ab0 | 2010-11-23 15:34:37 -0800 | [diff] [blame] | 848 | startAfterEdge(start, end, end, (int) mCurrVelocity); |
| 849 | } |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 850 | } |
| 851 | |
| 852 | private void onEdgeReached() { |
| 853 | // mStart, mVelocity and mStartTime were adjusted to their values when edge was reached. |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 854 | float distance = mVelocity * mVelocity / (2.0f * Math.abs(mDeceleration)); |
| 855 | final float sign = Math.signum(mVelocity); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 856 | |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 857 | if (distance > mOver) { |
| 858 | // Default deceleration is not sufficient to slow us down before boundary |
| 859 | mDeceleration = - sign * mVelocity * mVelocity / (2.0f * mOver); |
| 860 | distance = mOver; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 861 | } |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 862 | |
| 863 | mOver = (int) distance; |
| 864 | mState = BALLISTIC; |
| 865 | mFinal = mStart + (int) (mVelocity > 0 ? distance : -distance); |
| 866 | mDuration = - (int) (1000.0f * mVelocity / mDeceleration); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 867 | } |
| 868 | |
| 869 | boolean continueWhenFinished() { |
| 870 | switch (mState) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 871 | case SPLINE: |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 872 | // Duration from start to null velocity |
| 873 | if (mDuration < mSplineDuration) { |
| 874 | // If the animation was clamped, we reached the edge |
| 875 | mStart = mFinal; |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 876 | // TODO Better compute speed when edge was reached |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 877 | mVelocity = (int) mCurrVelocity; |
| 878 | mDeceleration = getDeceleration(mVelocity); |
| 879 | mStartTime += mDuration; |
| 880 | onEdgeReached(); |
| 881 | } else { |
| 882 | // Normal stop, no need to continue |
| 883 | return false; |
| 884 | } |
| 885 | break; |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 886 | case BALLISTIC: |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 887 | mStartTime += mDuration; |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 888 | startSpringback(mFinal, mStart, 0); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 889 | break; |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 890 | case CUBIC: |
| 891 | return false; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 892 | } |
| 893 | |
| 894 | update(); |
| 895 | return true; |
| 896 | } |
| 897 | |
| 898 | /* |
| 899 | * Update the current position and velocity for current time. Returns |
| 900 | * true if update has been done and false if animation duration has been |
| 901 | * reached. |
| 902 | */ |
| 903 | boolean update() { |
| 904 | final long time = AnimationUtils.currentAnimationTimeMillis(); |
| 905 | final long currentTime = time - mStartTime; |
| 906 | |
| 907 | if (currentTime > mDuration) { |
| 908 | return false; |
| 909 | } |
| 910 | |
| 911 | double distance = 0.0; |
| 912 | switch (mState) { |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 913 | case SPLINE: { |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 914 | final float t = (float) currentTime / mSplineDuration; |
| 915 | final int index = (int) (NB_SAMPLES * t); |
| 916 | float distanceCoef = 1.f; |
| 917 | float velocityCoef = 0.f; |
| 918 | if (index < NB_SAMPLES) { |
| 919 | final float t_inf = (float) index / NB_SAMPLES; |
| 920 | final float t_sup = (float) (index + 1) / NB_SAMPLES; |
| 921 | final float d_inf = SPLINE_POSITION[index]; |
| 922 | final float d_sup = SPLINE_POSITION[index + 1]; |
| 923 | velocityCoef = (d_sup - d_inf) / (t_sup - t_inf); |
| 924 | distanceCoef = d_inf + (t - t_inf) * velocityCoef; |
| 925 | } |
| 926 | |
| 927 | distance = distanceCoef * mSplineDistance; |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 928 | mCurrVelocity = velocityCoef * mSplineDistance / mSplineDuration * 1000.0f; |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 929 | break; |
| 930 | } |
| 931 | |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 932 | case BALLISTIC: { |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 933 | final float t = currentTime / 1000.0f; |
| 934 | mCurrVelocity = mVelocity + mDeceleration * t; |
| 935 | distance = mVelocity * t + mDeceleration * t * t / 2.0f; |
| 936 | break; |
| 937 | } |
| 938 | |
Gilles Debunne | c35a829 | 2010-12-10 14:36:17 -0800 | [diff] [blame] | 939 | case CUBIC: { |
| 940 | final float t = (float) (currentTime) / mDuration; |
| 941 | final float t2 = t * t; |
| 942 | final float sign = Math.signum(mVelocity); |
| 943 | distance = sign * mOver * (3.0f * t2 - 2.0f * t * t2); |
| 944 | mCurrVelocity = sign * mOver * 6.0f * (- t + t2); |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 945 | break; |
| 946 | } |
| 947 | } |
| 948 | |
| 949 | mCurrentPosition = mStart + (int) Math.round(distance); |
Gilles Debunne | 34961cc | 2010-12-14 15:25:36 -0800 | [diff] [blame] | 950 | |
Adam Powell | 637d337 | 2010-08-25 14:37:03 -0700 | [diff] [blame] | 951 | return true; |
| 952 | } |
| 953 | } |
| 954 | } |