PowerManager.java revision 237a29923a05663a2195bf93b392768dbaf31ebf
1/* 2 * Copyright (C) 2007 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.os; 18 19import android.util.Log; 20 21import com.android.internal.os.RuntimeInit; 22 23/** 24 * This class gives you control of the power state of the device. 25 * 26 * <p><b>Device battery life will be significantly affected by the use of this API.</b> Do not 27 * acquire WakeLocks unless you really need them, use the minimum levels possible, and be sure 28 * to release it as soon as you can. 29 * 30 * <p>You can obtain an instance of this class by calling 31 * {@link android.content.Context#getSystemService(java.lang.String) Context.getSystemService()}. 32 * 33 * <p>The primary API you'll use is {@link #newWakeLock(int, String) newWakeLock()}. This will 34 * create a {@link PowerManager.WakeLock} object. You can then use methods on this object to 35 * control the power state of the device. In practice it's quite simple: 36 * 37 * {@samplecode 38 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 39 * PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag"); 40 * wl.acquire(); 41 * ..screen will stay on during this section.. 42 * wl.release(); 43 * } 44 * 45 * <p>The following flags are defined, with varying effects on system power. <i>These flags are 46 * mutually exclusive - you may only specify one of them.</i> 47 * <table border="2" width="85%" align="center" frame="hsides" rules="rows"> 48 * 49 * <thead> 50 * <tr><th>Flag Value</th> 51 * <th>CPU</th> <th>Screen</th> <th>Keyboard</th></tr> 52 * </thead> 53 * 54 * <tbody> 55 * <tr><th>{@link #PARTIAL_WAKE_LOCK}</th> 56 * <td>On*</td> <td>Off</td> <td>Off</td> 57 * </tr> 58 * 59 * <tr><th>{@link #SCREEN_DIM_WAKE_LOCK}</th> 60 * <td>On</td> <td>Dim</td> <td>Off</td> 61 * </tr> 62 * 63 * <tr><th>{@link #SCREEN_BRIGHT_WAKE_LOCK}</th> 64 * <td>On</td> <td>Bright</td> <td>Off</td> 65 * </tr> 66 * 67 * <tr><th>{@link #FULL_WAKE_LOCK}</th> 68 * <td>On</td> <td>Bright</td> <td>Bright</td> 69 * </tr> 70 * </tbody> 71 * </table> 72 * 73 * <p>*<i>If you hold a partial wakelock, the CPU will continue to run, irrespective of any timers 74 * and even after the user presses the power button. In all other wakelocks, the CPU will run, but 75 * the user can still put the device to sleep using the power button.</i> 76 * 77 * <p>In addition, you can add two more flags, which affect behavior of the screen only. <i>These 78 * flags have no effect when combined with a {@link #PARTIAL_WAKE_LOCK}.</i> 79 * <table border="2" width="85%" align="center" frame="hsides" rules="rows"> 80 * 81 * <thead> 82 * <tr><th>Flag Value</th> <th>Description</th></tr> 83 * </thead> 84 * 85 * <tbody> 86 * <tr><th>{@link #ACQUIRE_CAUSES_WAKEUP}</th> 87 * <td>Normal wake locks don't actually turn on the illumination. Instead, they cause 88 * the illumination to remain on once it turns on (e.g. from user activity). This flag 89 * will force the screen and/or keyboard to turn on immediately, when the WakeLock is 90 * acquired. A typical use would be for notifications which are important for the user to 91 * see immediately.</td> 92 * </tr> 93 * 94 * <tr><th>{@link #ON_AFTER_RELEASE}</th> 95 * <td>If this flag is set, the user activity timer will be reset when the WakeLock is 96 * released, causing the illumination to remain on a bit longer. This can be used to 97 * reduce flicker if you are cycling between wake lock conditions.</td> 98 * </tr> 99 * </tbody> 100 * </table> 101 * 102 * 103 */ 104public class PowerManager 105{ 106 private static final String TAG = "PowerManager"; 107 108 /** 109 * These internal values define the underlying power elements that we might 110 * want to control individually. Eventually we'd like to expose them. 111 */ 112 private static final int WAKE_BIT_CPU_STRONG = 1; 113 private static final int WAKE_BIT_CPU_WEAK = 2; 114 private static final int WAKE_BIT_SCREEN_DIM = 4; 115 private static final int WAKE_BIT_SCREEN_BRIGHT = 8; 116 private static final int WAKE_BIT_KEYBOARD_BRIGHT = 16; 117 private static final int WAKE_BIT_PROXIMITY_SCREEN_OFF = 32; 118 119 private static final int LOCK_MASK = WAKE_BIT_CPU_STRONG 120 | WAKE_BIT_CPU_WEAK 121 | WAKE_BIT_SCREEN_DIM 122 | WAKE_BIT_SCREEN_BRIGHT 123 | WAKE_BIT_KEYBOARD_BRIGHT 124 | WAKE_BIT_PROXIMITY_SCREEN_OFF; 125 126 /** 127 * Wake lock that ensures that the CPU is running. The screen might 128 * not be on. 129 */ 130 public static final int PARTIAL_WAKE_LOCK = WAKE_BIT_CPU_STRONG; 131 132 /** 133 * Wake lock that ensures that the screen and keyboard are on at 134 * full brightness. 135 */ 136 public static final int FULL_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_BRIGHT 137 | WAKE_BIT_KEYBOARD_BRIGHT; 138 139 /** 140 * Wake lock that ensures that the screen is on at full brightness; 141 * the keyboard backlight will be allowed to go off. 142 */ 143 public static final int SCREEN_BRIGHT_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_BRIGHT; 144 145 /** 146 * Wake lock that ensures that the screen is on (but may be dimmed); 147 * the keyboard backlight will be allowed to go off. 148 */ 149 public static final int SCREEN_DIM_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_DIM; 150 151 /** 152 * Wake lock that turns the screen off when the proximity sensor activates. 153 * Since not all devices have proximity sensors, use 154 * {@link #getSupportedWakeLockFlags() getSupportedWakeLockFlags()} to determine if 155 * this wake lock mode is supported. 156 * 157 * {@hide} 158 */ 159 public static final int PROXIMITY_SCREEN_OFF_WAKE_LOCK = WAKE_BIT_PROXIMITY_SCREEN_OFF; 160 161 /** 162 * Normally wake locks don't actually wake the device, they just cause 163 * it to remain on once it's already on. Think of the video player 164 * app as the normal behavior. Notifications that pop up and want 165 * the device to be on are the exception; use this flag to be like them. 166 * <p> 167 * Does not work with PARTIAL_WAKE_LOCKs. 168 */ 169 public static final int ACQUIRE_CAUSES_WAKEUP = 0x10000000; 170 171 /** 172 * When this wake lock is released, poke the user activity timer 173 * so the screen stays on for a little longer. 174 * <p> 175 * Will not turn the screen on if it is not already on. See {@link #ACQUIRE_CAUSES_WAKEUP} 176 * if you want that. 177 * <p> 178 * Does not work with PARTIAL_WAKE_LOCKs. 179 */ 180 public static final int ON_AFTER_RELEASE = 0x20000000; 181 182 /** 183 * Class lets you say that you need to have the device on. 184 * 185 * <p>Call release when you are done and don't need the lock anymore. 186 */ 187 public class WakeLock 188 { 189 static final int RELEASE_WAKE_LOCK = 1; 190 191 Runnable mReleaser = new Runnable() { 192 public void run() { 193 release(); 194 } 195 }; 196 197 int mFlags; 198 String mTag; 199 IBinder mToken; 200 int mCount = 0; 201 boolean mRefCounted = true; 202 boolean mHeld = false; 203 204 WakeLock(int flags, String tag) 205 { 206 switch (flags & LOCK_MASK) { 207 case PARTIAL_WAKE_LOCK: 208 case SCREEN_DIM_WAKE_LOCK: 209 case SCREEN_BRIGHT_WAKE_LOCK: 210 case FULL_WAKE_LOCK: 211 case PROXIMITY_SCREEN_OFF_WAKE_LOCK: 212 break; 213 default: 214 throw new IllegalArgumentException(); 215 } 216 217 mFlags = flags; 218 mTag = tag; 219 mToken = new Binder(); 220 } 221 222 /** 223 * Sets whether this WakeLock is ref counted. 224 * 225 * @param value true for ref counted, false for not ref counted. 226 */ 227 public void setReferenceCounted(boolean value) 228 { 229 mRefCounted = value; 230 } 231 232 /** 233 * Makes sure the device is on at the level you asked when you created 234 * the wake lock. 235 */ 236 public void acquire() 237 { 238 synchronized (mToken) { 239 if (!mRefCounted || mCount++ == 0) { 240 try { 241 mService.acquireWakeLock(mFlags, mToken, mTag); 242 } catch (RemoteException e) { 243 } 244 mHeld = true; 245 } 246 } 247 } 248 249 /** 250 * Makes sure the device is on at the level you asked when you created 251 * the wake lock. The lock will be released after the given timeout. 252 * 253 * @param timeout Release the lock after the give timeout in milliseconds. 254 */ 255 public void acquire(long timeout) { 256 acquire(); 257 mHandler.postDelayed(mReleaser, timeout); 258 } 259 260 261 /** 262 * Release your claim to the CPU or screen being on. 263 * 264 * <p> 265 * It may turn off shortly after you release it, or it may not if there 266 * are other wake locks held. 267 */ 268 public void release() 269 { 270 synchronized (mToken) { 271 if (!mRefCounted || --mCount == 0) { 272 try { 273 mService.releaseWakeLock(mToken); 274 } catch (RemoteException e) { 275 } 276 mHeld = false; 277 } 278 if (mCount < 0) { 279 throw new RuntimeException("WakeLock under-locked " + mTag); 280 } 281 } 282 } 283 284 public boolean isHeld() 285 { 286 synchronized (mToken) { 287 return mHeld; 288 } 289 } 290 291 public String toString() { 292 synchronized (mToken) { 293 return "WakeLock{" 294 + Integer.toHexString(System.identityHashCode(this)) 295 + " held=" + mHeld + ", refCount=" + mCount + "}"; 296 } 297 } 298 299 @Override 300 protected void finalize() throws Throwable 301 { 302 synchronized (mToken) { 303 if (mHeld) { 304 try { 305 mService.releaseWakeLock(mToken); 306 } catch (RemoteException e) { 307 } 308 RuntimeInit.crash(TAG, new Exception( 309 "WakeLock finalized while still held: "+mTag)); 310 } 311 } 312 } 313 } 314 315 /** 316 * Get a wake lock at the level of the flags parameter. Call 317 * {@link WakeLock#acquire() acquire()} on the object to acquire the 318 * wake lock, and {@link WakeLock#release release()} when you are done. 319 * 320 * {@samplecode 321 *PowerManager pm = (PowerManager)mContext.getSystemService( 322 * Context.POWER_SERVICE); 323 *PowerManager.WakeLock wl = pm.newWakeLock( 324 * PowerManager.SCREEN_DIM_WAKE_LOCK 325 * | PowerManager.ON_AFTER_RELEASE, 326 * TAG); 327 *wl.acquire(); 328 * // ... 329 *wl.release(); 330 * } 331 * 332 * @param flags Combination of flag values defining the requested behavior of the WakeLock. 333 * @param tag Your class name (or other tag) for debugging purposes. 334 * 335 * @see WakeLock#acquire() 336 * @see WakeLock#release() 337 */ 338 public WakeLock newWakeLock(int flags, String tag) 339 { 340 return new WakeLock(flags, tag); 341 } 342 343 /** 344 * User activity happened. 345 * <p> 346 * Turns the device from whatever state it's in to full on, and resets 347 * the auto-off timer. 348 * 349 * @param when is used to order this correctly with the wake lock calls. 350 * This time should be in the {@link SystemClock#uptimeMillis 351 * SystemClock.uptimeMillis()} time base. 352 * @param noChangeLights should be true if you don't want the lights to 353 * turn on because of this event. This is set when the power 354 * key goes down. We want the device to stay on while the button 355 * is down, but we're about to turn off. Otherwise the lights 356 * flash on and then off and it looks weird. 357 */ 358 public void userActivity(long when, boolean noChangeLights) 359 { 360 try { 361 mService.userActivity(when, noChangeLights); 362 } catch (RemoteException e) { 363 } 364 } 365 366 /** 367 * Force the device to go to sleep. Overrides all the wake locks that are 368 * held. 369 * 370 * @param time is used to order this correctly with the wake lock calls. 371 * The time should be in the {@link SystemClock#uptimeMillis 372 * SystemClock.uptimeMillis()} time base. 373 */ 374 public void goToSleep(long time) 375 { 376 try { 377 mService.goToSleep(time); 378 } catch (RemoteException e) { 379 } 380 } 381 382 /** 383 * sets the brightness of the backlights (screen, keyboard, button). 384 * 385 * @param brightness value from 0 to 255 386 * 387 * {@hide} 388 */ 389 public void setBacklightBrightness(int brightness) 390 { 391 try { 392 mService.setBacklightBrightness(brightness); 393 } catch (RemoteException e) { 394 } 395 } 396 397 /** 398 * Returns the set of flags for {@link #newWakeLock(int, String) newWakeLock()} 399 * that are supported on the device. 400 * For example, to test to see if the {@link #PROXIMITY_SCREEN_OFF_WAKE_LOCK} 401 * is supported: 402 * 403 * {@samplecode 404 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 405 * int supportedFlags = pm.getSupportedWakeLockFlags(); 406 * boolean proximitySupported = ((supportedFlags & PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK) 407 * == PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK); 408 * } 409 * 410 * @return the set of supported WakeLock flags. 411 * 412 * {@hide} 413 */ 414 public int getSupportedWakeLockFlags() 415 { 416 try { 417 return mService.getSupportedWakeLockFlags(); 418 } catch (RemoteException e) { 419 return 0; 420 } 421 } 422 423 private PowerManager() 424 { 425 } 426 427 /** 428 * {@hide} 429 */ 430 public PowerManager(IPowerManager service, Handler handler) 431 { 432 mService = service; 433 mHandler = handler; 434 } 435 436 /** 437 * TODO: It would be nice to be able to set the poke lock here, 438 * but I'm not sure what would be acceptable as an interface - 439 * either a PokeLock object (like WakeLock) or, possibly just a 440 * method call to set the poke lock. 441 */ 442 443 IPowerManager mService; 444 Handler mHandler; 445} 446 447