AnimationDrawable.java revision 70e68e0ff17f3d47f382b6ac0e6a7eb49be17965
1/* 2 * Copyright (C) 2006 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 android.graphics.drawable; 18 19import com.android.internal.R; 20 21import java.io.IOException; 22 23import org.xmlpull.v1.XmlPullParser; 24import org.xmlpull.v1.XmlPullParserException; 25 26import android.annotation.NonNull; 27import android.content.res.Resources; 28import android.content.res.TypedArray; 29import android.content.res.Resources.Theme; 30import android.os.SystemClock; 31import android.util.AttributeSet; 32 33/** 34 * An object used to create frame-by-frame animations, defined by a series of 35 * Drawable objects, which can be used as a View object's background. 36 * <p> 37 * The simplest way to create a frame-by-frame animation is to define the 38 * animation in an XML file, placed in the res/drawable/ folder, and set it as 39 * the background to a View object. Then, call {@link #start()} to run the 40 * animation. 41 * <p> 42 * An AnimationDrawable defined in XML consists of a single 43 * {@code <animation-list>} element and a series of nested 44 * {@code <item>} tags. Each item defines a frame of the animation. See 45 * the example below. 46 * <p> 47 * spin_animation.xml file in res/drawable/ folder: 48 * <pre> 49 * <!-- Animation frames are wheel0.png through wheel5.png 50 * files inside the res/drawable/ folder --> 51 * <animation-list android:id="@+id/selected" android:oneshot="false"> 52 * <item android:drawable="@drawable/wheel0" android:duration="50" /> 53 * <item android:drawable="@drawable/wheel1" android:duration="50" /> 54 * <item android:drawable="@drawable/wheel2" android:duration="50" /> 55 * <item android:drawable="@drawable/wheel3" android:duration="50" /> 56 * <item android:drawable="@drawable/wheel4" android:duration="50" /> 57 * <item android:drawable="@drawable/wheel5" android:duration="50" /> 58 * </animation-list></pre> 59 * <p> 60 * Here is the code to load and play this animation. 61 * <pre> 62 * // Load the ImageView that will host the animation and 63 * // set its background to our AnimationDrawable XML resource. 64 * ImageView img = (ImageView)findViewById(R.id.spinning_wheel_image); 65 * img.setBackgroundResource(R.drawable.spin_animation); 66 * 67 * // Get the background, which has been compiled to an AnimationDrawable object. 68 * AnimationDrawable frameAnimation = (AnimationDrawable) img.getBackground(); 69 * 70 * // Start the animation (looped playback by default). 71 * frameAnimation.start(); 72 * </pre> 73 * 74 * <div class="special reference"> 75 * <h3>Developer Guides</h3> 76 * <p>For more information about animating with {@code AnimationDrawable}, read the 77 * <a href="{@docRoot}guide/topics/graphics/drawable-animation.html">Drawable Animation</a> 78 * developer guide.</p> 79 * </div> 80 * 81 * @attr ref android.R.styleable#AnimationDrawable_visible 82 * @attr ref android.R.styleable#AnimationDrawable_variablePadding 83 * @attr ref android.R.styleable#AnimationDrawable_oneshot 84 * @attr ref android.R.styleable#AnimationDrawableItem_duration 85 * @attr ref android.R.styleable#AnimationDrawableItem_drawable 86 */ 87public class AnimationDrawable extends DrawableContainer implements Runnable, Animatable { 88 private AnimationState mAnimationState; 89 90 /** The current frame, may be -1 when not animating. */ 91 private int mCurFrame = -1; 92 93 /** Whether the drawable has an animation callback posted. */ 94 private boolean mRunning; 95 96 /** Whether the drawable should animate when visible. */ 97 private boolean mAnimating; 98 99 private boolean mMutated; 100 101 public AnimationDrawable() { 102 this(null, null); 103 } 104 105 /** 106 * Sets whether this AnimationDrawable is visible. 107 * <p> 108 * When the drawable becomes invisible, it will pause its animation. A 109 * subsequent change to visible with <code>restart</code> set to true will 110 * restart the animation from the first frame. If <code>restart</code> is 111 * false, the animation will resume from the most recent frame. 112 * 113 * @param visible true if visible, false otherwise 114 * @param restart when visible, true to force the animation to restart 115 * from the first frame 116 * @return true if the new visibility is different than its previous state 117 */ 118 @Override 119 public boolean setVisible(boolean visible, boolean restart) { 120 final boolean changed = super.setVisible(visible, restart); 121 if (visible) { 122 if (restart || changed) { 123 boolean startFromZero = restart || mCurFrame < 0 || 124 mCurFrame >= mAnimationState.getChildCount(); 125 setFrame(startFromZero ? 0 : mCurFrame, true, mAnimating); 126 } 127 } else { 128 unscheduleSelf(this); 129 } 130 return changed; 131 } 132 133 /** 134 * Starts the animation, looping if necessary. This method has no effect 135 * if the animation is running. 136 * <p> 137 * <strong>Note:</strong> Do not call this in the 138 * {@link android.app.Activity#onCreate} method of your activity, because 139 * the {@link AnimationDrawable} is not yet fully attached to the window. 140 * If you want to play the animation immediately without requiring 141 * interaction, then you might want to call it from the 142 * {@link android.app.Activity#onWindowFocusChanged} method in your 143 * activity, which will get called when Android brings your window into 144 * focus. 145 * 146 * @see #isRunning() 147 * @see #stop() 148 */ 149 @Override 150 public void start() { 151 mAnimating = true; 152 153 if (!isRunning()) { 154 run(); 155 } 156 } 157 158 /** 159 * Stops the animation. This method has no effect if the animation is not 160 * running. 161 * 162 * @see #isRunning() 163 * @see #start() 164 */ 165 @Override 166 public void stop() { 167 mAnimating = false; 168 169 if (isRunning()) { 170 unscheduleSelf(this); 171 } 172 } 173 174 /** 175 * Indicates whether the animation is currently running or not. 176 * 177 * @return true if the animation is running, false otherwise 178 */ 179 @Override 180 public boolean isRunning() { 181 return mRunning; 182 } 183 184 /** 185 * This method exists for implementation purpose only and should not be 186 * called directly. Invoke {@link #start()} instead. 187 * 188 * @see #start() 189 */ 190 @Override 191 public void run() { 192 nextFrame(false); 193 } 194 195 @Override 196 public void unscheduleSelf(Runnable what) { 197 mCurFrame = -1; 198 mRunning = false; 199 super.unscheduleSelf(what); 200 } 201 202 /** 203 * @return The number of frames in the animation 204 */ 205 public int getNumberOfFrames() { 206 return mAnimationState.getChildCount(); 207 } 208 209 /** 210 * @return The Drawable at the specified frame index 211 */ 212 public Drawable getFrame(int index) { 213 return mAnimationState.getChild(index); 214 } 215 216 /** 217 * @return The duration in milliseconds of the frame at the 218 * specified index 219 */ 220 public int getDuration(int i) { 221 return mAnimationState.mDurations[i]; 222 } 223 224 /** 225 * @return True of the animation will play once, false otherwise 226 */ 227 public boolean isOneShot() { 228 return mAnimationState.mOneShot; 229 } 230 231 /** 232 * Sets whether the animation should play once or repeat. 233 * 234 * @param oneShot Pass true if the animation should only play once 235 */ 236 public void setOneShot(boolean oneShot) { 237 mAnimationState.mOneShot = oneShot; 238 } 239 240 /** 241 * Adds a frame to the animation 242 * 243 * @param frame The frame to add 244 * @param duration How long in milliseconds the frame should appear 245 */ 246 public void addFrame(@NonNull Drawable frame, int duration) { 247 mAnimationState.addFrame(frame, duration); 248 if (mCurFrame < 0) { 249 setFrame(0, true, false); 250 } 251 } 252 253 private void nextFrame(boolean unschedule) { 254 int nextFrame = mCurFrame + 1; 255 final int numFrames = mAnimationState.getChildCount(); 256 final boolean isLastFrame = mAnimationState.mOneShot && nextFrame >= (numFrames - 1); 257 258 // Loop if necessary. One-shot animations should never hit this case. 259 if (!mAnimationState.mOneShot && nextFrame >= numFrames) { 260 nextFrame = 0; 261 } 262 263 setFrame(nextFrame, unschedule, !isLastFrame); 264 } 265 266 private void setFrame(int frame, boolean unschedule, boolean animate) { 267 if (frame >= mAnimationState.getChildCount()) { 268 return; 269 } 270 mAnimating = animate; 271 mCurFrame = frame; 272 selectDrawable(frame); 273 if (unschedule || animate) { 274 unscheduleSelf(this); 275 mRunning = false; 276 } 277 if (animate) { 278 // Unscheduling may have clobbered these values; restore them 279 mCurFrame = frame; 280 mRunning = true; 281 scheduleSelf(this, SystemClock.uptimeMillis() + mAnimationState.mDurations[frame]); 282 } 283 } 284 285 @Override 286 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 287 throws XmlPullParserException, IOException { 288 final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.AnimationDrawable); 289 super.inflateWithAttributes(r, parser, a, R.styleable.AnimationDrawable_visible); 290 updateStateFromTypedArray(a); 291 a.recycle(); 292 293 inflateChildElements(r, parser, attrs, theme); 294 295 setFrame(0, true, false); 296 } 297 298 private void inflateChildElements(Resources r, XmlPullParser parser, AttributeSet attrs, 299 Theme theme) throws XmlPullParserException, IOException { 300 int type; 301 302 final int innerDepth = parser.getDepth()+1; 303 int depth; 304 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT 305 && ((depth = parser.getDepth()) >= innerDepth || type != XmlPullParser.END_TAG)) { 306 if (type != XmlPullParser.START_TAG) { 307 continue; 308 } 309 310 if (depth > innerDepth || !parser.getName().equals("item")) { 311 continue; 312 } 313 314 final TypedArray a = obtainAttributes(r, theme, attrs, 315 R.styleable.AnimationDrawableItem); 316 317 final int duration = a.getInt(R.styleable.AnimationDrawableItem_duration, -1); 318 if (duration < 0) { 319 throw new XmlPullParserException(parser.getPositionDescription() 320 + ": <item> tag requires a 'duration' attribute"); 321 } 322 323 Drawable dr = a.getDrawable(R.styleable.AnimationDrawableItem_drawable); 324 325 a.recycle(); 326 327 if (dr == null) { 328 while ((type=parser.next()) == XmlPullParser.TEXT) { 329 // Empty 330 } 331 if (type != XmlPullParser.START_TAG) { 332 throw new XmlPullParserException(parser.getPositionDescription() 333 + ": <item> tag requires a 'drawable' attribute or child tag" 334 + " defining a drawable"); 335 } 336 dr = Drawable.createFromXmlInner(r, parser, attrs, theme); 337 } 338 339 mAnimationState.addFrame(dr, duration); 340 if (dr != null) { 341 dr.setCallback(this); 342 } 343 } 344 } 345 346 private void updateStateFromTypedArray(TypedArray a) { 347 mAnimationState.mVariablePadding = a.getBoolean( 348 R.styleable.AnimationDrawable_variablePadding, mAnimationState.mVariablePadding); 349 350 mAnimationState.mOneShot = a.getBoolean( 351 R.styleable.AnimationDrawable_oneshot, mAnimationState.mOneShot); 352 } 353 354 @Override 355 @NonNull 356 public Drawable mutate() { 357 if (!mMutated && super.mutate() == this) { 358 mAnimationState.mutate(); 359 mMutated = true; 360 } 361 return this; 362 } 363 364 @Override 365 AnimationState cloneConstantState() { 366 return new AnimationState(mAnimationState, this, null); 367 } 368 369 /** 370 * @hide 371 */ 372 public void clearMutated() { 373 super.clearMutated(); 374 mMutated = false; 375 } 376 377 private final static class AnimationState extends DrawableContainerState { 378 private int[] mDurations; 379 private boolean mOneShot = false; 380 381 AnimationState(AnimationState orig, AnimationDrawable owner, Resources res) { 382 super(orig, owner, res); 383 384 if (orig != null) { 385 mDurations = orig.mDurations; 386 mOneShot = orig.mOneShot; 387 } else { 388 mDurations = new int[getCapacity()]; 389 mOneShot = false; 390 } 391 } 392 393 private void mutate() { 394 mDurations = mDurations.clone(); 395 } 396 397 @Override 398 public Drawable newDrawable() { 399 return new AnimationDrawable(this, null); 400 } 401 402 @Override 403 public Drawable newDrawable(Resources res) { 404 return new AnimationDrawable(this, res); 405 } 406 407 public void addFrame(Drawable dr, int dur) { 408 // Do not combine the following. The array index must be evaluated before 409 // the array is accessed because super.addChild(dr) has a side effect on mDurations. 410 int pos = super.addChild(dr); 411 mDurations[pos] = dur; 412 } 413 414 @Override 415 public void growArray(int oldSize, int newSize) { 416 super.growArray(oldSize, newSize); 417 int[] newDurations = new int[newSize]; 418 System.arraycopy(mDurations, 0, newDurations, 0, oldSize); 419 mDurations = newDurations; 420 } 421 } 422 423 @Override 424 protected void setConstantState(@NonNull DrawableContainerState state) { 425 super.setConstantState(state); 426 427 if (state instanceof AnimationState) { 428 mAnimationState = (AnimationState) state; 429 } 430 } 431 432 private AnimationDrawable(AnimationState state, Resources res) { 433 final AnimationState as = new AnimationState(state, this, res); 434 setConstantState(as); 435 if (state != null) { 436 setFrame(0, true, false); 437 } 438 } 439} 440 441