AnimationDrawable.java revision 4b17118aca1e67963254ab83504b0753a3eac7ce
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 java.io.IOException; 20 21import org.xmlpull.v1.XmlPullParser; 22import org.xmlpull.v1.XmlPullParserException; 23 24import android.content.res.Resources; 25import android.content.res.TypedArray; 26import android.content.res.Resources.Theme; 27import android.os.SystemClock; 28import android.util.AttributeSet; 29 30/** 31 * An object used to create frame-by-frame animations, defined by a series of Drawable objects, 32 * which can be used as a View object's background. 33 * <p> 34 * The simplest way to create a frame-by-frame animation is to define the animation in an XML 35 * file, placed in the res/drawable/ folder, and set it as the background to a View object. Then, call 36 * {@link #start()} to run the animation. 37 * <p> 38 * An AnimationDrawable defined in XML consists of a single <code><animation-list></code> element, 39 * and a series of nested <code><item></code> tags. Each item defines a frame of the animation. 40 * See the example below. 41 * </p> 42 * <p>spin_animation.xml file in res/drawable/ folder:</p> 43 * <pre><!-- Animation frames are wheel0.png -- wheel5.png files inside the 44 * res/drawable/ folder --> 45 * <animation-list android:id="@+id/selected" android:oneshot="false"> 46 * <item android:drawable="@drawable/wheel0" android:duration="50" /> 47 * <item android:drawable="@drawable/wheel1" android:duration="50" /> 48 * <item android:drawable="@drawable/wheel2" android:duration="50" /> 49 * <item android:drawable="@drawable/wheel3" android:duration="50" /> 50 * <item android:drawable="@drawable/wheel4" android:duration="50" /> 51 * <item android:drawable="@drawable/wheel5" android:duration="50" /> 52 * </animation-list></pre> 53 * 54 * <p>Here is the code to load and play this animation.</p> 55 * <pre> 56 * // Load the ImageView that will host the animation and 57 * // set its background to our AnimationDrawable XML resource. 58 * ImageView img = (ImageView)findViewById(R.id.spinning_wheel_image); 59 * img.setBackgroundResource(R.drawable.spin_animation); 60 * 61 * // Get the background, which has been compiled to an AnimationDrawable object. 62 * AnimationDrawable frameAnimation = (AnimationDrawable) img.getBackground(); 63 * 64 * // Start the animation (looped playback by default). 65 * frameAnimation.start(); 66 * </pre> 67 * 68 * <div class="special reference"> 69 * <h3>Developer Guides</h3> 70 * <p>For more information about animating with {@code AnimationDrawable}, read the 71 * <a href="{@docRoot}guide/topics/graphics/drawable-animation.html">Drawable Animation</a> 72 * developer guide.</p> 73 * </div> 74 * 75 * @attr ref android.R.styleable#AnimationDrawable_visible 76 * @attr ref android.R.styleable#AnimationDrawable_variablePadding 77 * @attr ref android.R.styleable#AnimationDrawable_oneshot 78 * @attr ref android.R.styleable#AnimationDrawableItem_duration 79 * @attr ref android.R.styleable#AnimationDrawableItem_drawable 80 */ 81public class AnimationDrawable extends DrawableContainer implements Runnable, Animatable { 82 private final AnimationState mAnimationState; 83 private int mCurFrame = -1; 84 private boolean mAnimating; 85 private boolean mMutated; 86 87 public AnimationDrawable() { 88 this(null, null); 89 } 90 91 @Override 92 public boolean setVisible(boolean visible, boolean restart) { 93 final boolean changed = super.setVisible(visible, restart); 94 if (visible) { 95 if (changed || restart) { 96 setFrame(0, true, mAnimating); 97 } 98 } else { 99 unscheduleSelf(this); 100 } 101 return changed; 102 } 103 104 /** 105 * <p>Starts the animation, looping if necessary. This method has no effect 106 * if the animation is running. Do not call this in the {@link android.app.Activity#onCreate} 107 * method of your activity, because the {@link android.graphics.drawable.AnimationDrawable} is 108 * not yet fully attached to the window. If you want to play 109 * the animation immediately, without requiring interaction, then you might want to call it 110 * from the {@link android.app.Activity#onWindowFocusChanged} method in your activity, 111 * which will get called when Android brings your window into focus.</p> 112 * 113 * @see #isRunning() 114 * @see #stop() 115 */ 116 @Override 117 public void start() { 118 if (!isRunning()) { 119 run(); 120 } 121 } 122 123 /** 124 * <p>Stops the animation. This method has no effect if the animation is 125 * not running.</p> 126 * 127 * @see #isRunning() 128 * @see #start() 129 */ 130 @Override 131 public void stop() { 132 if (isRunning()) { 133 unscheduleSelf(this); 134 } 135 } 136 137 /** 138 * <p>Indicates whether the animation is currently running or not.</p> 139 * 140 * @return true if the animation is running, false otherwise 141 */ 142 @Override 143 public boolean isRunning() { 144 return mAnimating; 145 } 146 147 /** 148 * <p>This method exists for implementation purpose only and should not be 149 * called directly. Invoke {@link #start()} instead.</p> 150 * 151 * @see #start() 152 */ 153 @Override 154 public void run() { 155 nextFrame(false); 156 } 157 158 @Override 159 public void unscheduleSelf(Runnable what) { 160 mCurFrame = -1; 161 mAnimating = false; 162 super.unscheduleSelf(what); 163 } 164 165 /** 166 * @return The number of frames in the animation 167 */ 168 public int getNumberOfFrames() { 169 return mAnimationState.getChildCount(); 170 } 171 172 /** 173 * @return The Drawable at the specified frame index 174 */ 175 public Drawable getFrame(int index) { 176 return mAnimationState.getChild(index); 177 } 178 179 /** 180 * @return The duration in milliseconds of the frame at the 181 * specified index 182 */ 183 public int getDuration(int i) { 184 return mAnimationState.mDurations[i]; 185 } 186 187 /** 188 * @return True of the animation will play once, false otherwise 189 */ 190 public boolean isOneShot() { 191 return mAnimationState.mOneShot; 192 } 193 194 /** 195 * Sets whether the animation should play once or repeat. 196 * 197 * @param oneShot Pass true if the animation should only play once 198 */ 199 public void setOneShot(boolean oneShot) { 200 mAnimationState.mOneShot = oneShot; 201 } 202 203 /** 204 * Add a frame to the animation 205 * 206 * @param frame The frame to add 207 * @param duration How long in milliseconds the frame should appear 208 */ 209 public void addFrame(Drawable frame, int duration) { 210 mAnimationState.addFrame(frame, duration); 211 if (mCurFrame < 0) { 212 setFrame(0, true, false); 213 } 214 } 215 216 private void nextFrame(boolean unschedule) { 217 int next = mCurFrame+1; 218 final int N = mAnimationState.getChildCount(); 219 if (next >= N) { 220 next = 0; 221 } 222 setFrame(next, unschedule, !mAnimationState.mOneShot || next < (N - 1)); 223 } 224 225 private void setFrame(int frame, boolean unschedule, boolean animate) { 226 if (frame >= mAnimationState.getChildCount()) { 227 return; 228 } 229 mCurFrame = frame; 230 selectDrawable(frame); 231 if (unschedule || animate) { 232 unscheduleSelf(this); 233 } 234 if (animate) { 235 // Unscheduling may have clobbered these values; restore them 236 mCurFrame = frame; 237 mAnimating = true; 238 scheduleSelf(this, SystemClock.uptimeMillis() + mAnimationState.mDurations[frame]); 239 } 240 } 241 242 @Override 243 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 244 throws XmlPullParserException, IOException { 245 246 TypedArray a = r.obtainAttributes(attrs, 247 com.android.internal.R.styleable.AnimationDrawable); 248 249 super.inflateWithAttributes(r, parser, a, 250 com.android.internal.R.styleable.AnimationDrawable_visible); 251 252 mAnimationState.setVariablePadding(a.getBoolean( 253 com.android.internal.R.styleable.AnimationDrawable_variablePadding, false)); 254 255 mAnimationState.mOneShot = a.getBoolean( 256 com.android.internal.R.styleable.AnimationDrawable_oneshot, false); 257 258 a.recycle(); 259 260 int type; 261 262 final int innerDepth = parser.getDepth()+1; 263 int depth; 264 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT && 265 ((depth = parser.getDepth()) >= innerDepth || type != XmlPullParser.END_TAG)) { 266 if (type != XmlPullParser.START_TAG) { 267 continue; 268 } 269 270 if (depth > innerDepth || !parser.getName().equals("item")) { 271 continue; 272 } 273 274 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.AnimationDrawableItem); 275 int duration = a.getInt( 276 com.android.internal.R.styleable.AnimationDrawableItem_duration, -1); 277 if (duration < 0) { 278 throw new XmlPullParserException( 279 parser.getPositionDescription() 280 + ": <item> tag requires a 'duration' attribute"); 281 } 282 int drawableRes = a.getResourceId( 283 com.android.internal.R.styleable.AnimationDrawableItem_drawable, 0); 284 285 a.recycle(); 286 287 Drawable dr; 288 if (drawableRes != 0) { 289 dr = r.getDrawable(drawableRes); 290 } else { 291 while ((type=parser.next()) == XmlPullParser.TEXT) { 292 // Empty 293 } 294 if (type != XmlPullParser.START_TAG) { 295 throw new XmlPullParserException(parser.getPositionDescription() + 296 ": <item> tag requires a 'drawable' attribute or child tag" + 297 " defining a drawable"); 298 } 299 dr = Drawable.createFromXmlInner(r, parser, attrs, theme); 300 } 301 302 mAnimationState.addFrame(dr, duration); 303 if (dr != null) { 304 dr.setCallback(this); 305 } 306 } 307 308 setFrame(0, true, false); 309 } 310 311 @Override 312 public Drawable mutate() { 313 if (!mMutated && super.mutate() == this) { 314 mAnimationState.mDurations = mAnimationState.mDurations.clone(); 315 mMutated = true; 316 } 317 return this; 318 } 319 320 private final static class AnimationState extends DrawableContainerState { 321 private int[] mDurations; 322 private boolean mOneShot; 323 324 AnimationState(AnimationState orig, AnimationDrawable owner, 325 Resources res) { 326 super(orig, owner, res); 327 328 if (orig != null) { 329 mDurations = orig.mDurations; 330 mOneShot = orig.mOneShot; 331 } else { 332 mDurations = new int[getCapacity()]; 333 mOneShot = true; 334 } 335 } 336 337 @Override 338 public Drawable newDrawable() { 339 return new AnimationDrawable(this, null); 340 } 341 342 @Override 343 public Drawable newDrawable(Resources res) { 344 return new AnimationDrawable(this, res); 345 } 346 347 public void addFrame(Drawable dr, int dur) { 348 // Do not combine the following. The array index must be evaluated before 349 // the array is accessed because super.addChild(dr) has a side effect on mDurations. 350 int pos = super.addChild(dr); 351 mDurations[pos] = dur; 352 } 353 354 @Override 355 public void growArray(int oldSize, int newSize) { 356 super.growArray(oldSize, newSize); 357 int[] newDurations = new int[newSize]; 358 System.arraycopy(mDurations, 0, newDurations, 0, oldSize); 359 mDurations = newDurations; 360 } 361 } 362 363 private AnimationDrawable(AnimationState state, Resources res) { 364 AnimationState as = new AnimationState(state, this, res); 365 mAnimationState = as; 366 setConstantState(as); 367 if (state != null) { 368 setFrame(0, true, false); 369 } 370 } 371} 372 373