AnimationDrawable.java revision b798689749c64baba81f02e10cf2157c747d6b46
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.os.SystemClock; 27import android.util.AttributeSet; 28 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 #run()} to start 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="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 * @attr ref android.R.styleable#AnimationDrawable_visible 69 * @attr ref android.R.styleable#AnimationDrawable_variablePadding 70 * @attr ref android.R.styleable#AnimationDrawable_oneshot 71 * @attr ref android.R.styleable#AnimationDrawableItem_duration 72 * @attr ref android.R.styleable#AnimationDrawableItem_drawable 73 */ 74public class AnimationDrawable extends DrawableContainer implements Runnable { 75 private final AnimationState mAnimationState; 76 private int mCurFrame = -1; 77 78 public AnimationDrawable() { 79 this(null); 80 } 81 82 @Override 83 public boolean setVisible(boolean visible, boolean restart) { 84 boolean changed = super.setVisible(visible, restart); 85 if (visible) { 86 if (changed || restart) { 87 setFrame(0, true, true); 88 } 89 } else { 90 unscheduleSelf(this); 91 } 92 return changed; 93 } 94 95 /** 96 * <p>Starts the animation, looping if necessary. This method has no effect 97 * if the animation is running.</p> 98 * 99 * @see #isRunning() 100 * @see #stop() 101 */ 102 public void start() { 103 if (!isRunning()) { 104 run(); 105 } 106 } 107 108 /** 109 * <p>Stops the animation. This method has no effect if the animation is 110 * not running.</p> 111 * 112 * @see #isRunning() 113 * @see #start() 114 */ 115 public void stop() { 116 if (isRunning()) { 117 unscheduleSelf(this); 118 } 119 } 120 121 /** 122 * <p>Indicates whether the animation is currently running or not.</p> 123 * 124 * @return true if the animation is running, false otherwise 125 */ 126 public boolean isRunning() { 127 return mCurFrame > -1; 128 } 129 130 /** 131 * <p>This method exists for implementation purpose only and should not be 132 * called directly. Invoke {@link #start()} instead.</p> 133 * 134 * @see #start() 135 */ 136 public void run() { 137 nextFrame(false); 138 } 139 140 @Override 141 public void unscheduleSelf(Runnable what) { 142 mCurFrame = -1; 143 super.unscheduleSelf(what); 144 } 145 146 /** 147 * @return The number of frames in the animation 148 */ 149 public int getNumberOfFrames() { 150 return mAnimationState.getChildCount(); 151 } 152 153 /** 154 * @return The Drawable at the specified frame index 155 */ 156 public Drawable getFrame(int index) { 157 return mAnimationState.getChildren()[index]; 158 } 159 160 /** 161 * @return The duration in milliseconds of the frame at the 162 * specified index 163 */ 164 public int getDuration(int i) { 165 return mAnimationState.mDurations[i]; 166 } 167 168 /** 169 * @return True of the animation will play once, false otherwise 170 */ 171 public boolean isOneShot() { 172 return mAnimationState.mOneShot; 173 } 174 175 /** 176 * Sets whether the animation should play once or repeat. 177 * 178 * @param oneShot Pass true if the animation should only play once 179 */ 180 public void setOneShot(boolean oneShot) { 181 mAnimationState.mOneShot = oneShot; 182 } 183 184 /** 185 * Add a frame to the animation 186 * 187 * @param frame The frame to add 188 * @param duration How long in milliseconds the frame should appear 189 */ 190 public void addFrame(Drawable frame, int duration) { 191 mAnimationState.addFrame(frame, duration); 192 } 193 194 private void nextFrame(boolean unschedule) { 195 int next = mCurFrame+1; 196 final int N = mAnimationState.getChildCount(); 197 if (next >= N) { 198 next = 0; 199 } 200 setFrame(next, unschedule, !mAnimationState.mOneShot || next < (N - 1)); 201 } 202 203 private void setFrame(int frame, boolean unschedule, boolean animate) { 204 if (frame >= mAnimationState.getChildCount()) { 205 return; 206 } 207 mCurFrame = frame; 208 selectDrawable(frame); 209 if (unschedule) { 210 unscheduleSelf(this); 211 } 212 if (animate) { 213 scheduleSelf(this, SystemClock.uptimeMillis() + mAnimationState.mDurations[frame]); 214 } 215 } 216 217 @Override 218 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 219 throws XmlPullParserException, IOException { 220 221 TypedArray a = r.obtainAttributes(attrs, 222 com.android.internal.R.styleable.AnimationDrawable); 223 224 super.inflateWithAttributes(r, parser, a, 225 com.android.internal.R.styleable.AnimationDrawable_visible); 226 227 mAnimationState.setVariablePadding(a.getBoolean( 228 com.android.internal.R.styleable.AnimationDrawable_variablePadding, false)); 229 230 mAnimationState.mOneShot = a.getBoolean( 231 com.android.internal.R.styleable.AnimationDrawable_oneshot, false); 232 233 a.recycle(); 234 235 int type; 236 237 final int innerDepth = parser.getDepth()+1; 238 int depth; 239 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT && 240 ((depth = parser.getDepth()) >= innerDepth || type != XmlPullParser.END_TAG)) { 241 if (type != XmlPullParser.START_TAG) { 242 continue; 243 } 244 245 if (depth > innerDepth || !parser.getName().equals("item")) { 246 continue; 247 } 248 249 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.AnimationDrawableItem); 250 int duration = a.getInt( 251 com.android.internal.R.styleable.AnimationDrawableItem_duration, -1); 252 if (duration < 0) { 253 throw new XmlPullParserException( 254 parser.getPositionDescription() 255 + ": <item> tag requires a 'duration' attribute"); 256 } 257 int drawableRes = a.getResourceId( 258 com.android.internal.R.styleable.AnimationDrawableItem_drawable, 0); 259 260 a.recycle(); 261 262 Drawable dr; 263 if (drawableRes != 0) { 264 dr = r.getDrawable(drawableRes); 265 } else { 266 while ((type=parser.next()) == XmlPullParser.TEXT) { 267 // Empty 268 } 269 if (type != XmlPullParser.START_TAG) { 270 throw new XmlPullParserException(parser.getPositionDescription() + 271 ": <item> tag requires a 'drawable' attribute or child tag" + 272 " defining a drawable"); 273 } 274 dr = Drawable.createFromXmlInner(r, parser, attrs); 275 } 276 277 mAnimationState.addFrame(dr, duration); 278 if (dr != null) { 279 dr.setCallback(this); 280 } 281 } 282 283 setFrame(0, true, false); 284 } 285 286 private final static class AnimationState extends DrawableContainerState { 287 private int[] mDurations; 288 private boolean mOneShot; 289 290 AnimationState(AnimationState orig, AnimationDrawable owner) { 291 super(orig, owner); 292 293 if (orig != null) { 294 mDurations = orig.mDurations; 295 mOneShot = orig.mOneShot; 296 } else { 297 mDurations = new int[getChildren().length]; 298 mOneShot = true; 299 } 300 } 301 302 @Override 303 public Drawable newDrawable() { 304 return new AnimationDrawable(this); 305 } 306 307 public void addFrame(Drawable dr, int dur) { 308 // Do not combine the following. The array index must be evaluated before 309 // the array is accessed because super.addChild(dr) has a side effect on mDurations. 310 int pos = super.addChild(dr); 311 mDurations[pos] = dur; 312 } 313 314 @Override 315 public void growArray(int oldSize, int newSize) { 316 super.growArray(oldSize, newSize); 317 int[] newDurations = new int[newSize]; 318 System.arraycopy(mDurations, 0, newDurations, 0, oldSize); 319 mDurations = newDurations; 320 } 321 } 322 323 private AnimationDrawable(AnimationState state) { 324 AnimationState as = new AnimationState(state, this); 325 mAnimationState = as; 326 setConstantState(as); 327 if (state != null) { 328 setFrame(0, true, false); 329 } 330 } 331} 332 333