PowerManager.java revision d710fb500c121b3f9563ccfbe488f7c9d3ec4985
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 21/** 22 * This class gives you control of the power state of the device. 23 * 24 * <p><b>Device battery life will be significantly affected by the use of this API.</b> Do not 25 * acquire WakeLocks unless you really need them, use the minimum levels possible, and be sure 26 * to release it as soon as you can. 27 * 28 * <p>You can obtain an instance of this class by calling 29 * {@link android.content.Context#getSystemService(java.lang.String) Context.getSystemService()}. 30 * 31 * <p>The primary API you'll use is {@link #newWakeLock(int, String) newWakeLock()}. This will 32 * create a {@link PowerManager.WakeLock} object. You can then use methods on this object to 33 * control the power state of the device. In practice it's quite simple: 34 * 35 * {@samplecode 36 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 37 * PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag"); 38 * wl.acquire(); 39 * ..screen will stay on during this section.. 40 * wl.release(); 41 * } 42 * 43 * <p>The following flags are defined, with varying effects on system power. <i>These flags are 44 * mutually exclusive - you may only specify one of them.</i> 45 * <table border="2" width="85%" align="center" frame="hsides" rules="rows"> 46 * 47 * <thead> 48 * <tr><th>Flag Value</th> 49 * <th>CPU</th> <th>Screen</th> <th>Keyboard</th></tr> 50 * </thead> 51 * 52 * <tbody> 53 * <tr><th>{@link #PARTIAL_WAKE_LOCK}</th> 54 * <td>On*</td> <td>Off</td> <td>Off</td> 55 * </tr> 56 * 57 * <tr><th>{@link #SCREEN_DIM_WAKE_LOCK}</th> 58 * <td>On</td> <td>Dim</td> <td>Off</td> 59 * </tr> 60 * 61 * <tr><th>{@link #SCREEN_BRIGHT_WAKE_LOCK}</th> 62 * <td>On</td> <td>Bright</td> <td>Off</td> 63 * </tr> 64 * 65 * <tr><th>{@link #FULL_WAKE_LOCK}</th> 66 * <td>On</td> <td>Bright</td> <td>Bright</td> 67 * </tr> 68 * </tbody> 69 * </table> 70 * 71 * <p>*<i>If you hold a partial wakelock, the CPU will continue to run, irrespective of any timers 72 * and even after the user presses the power button. In all other wakelocks, the CPU will run, but 73 * the user can still put the device to sleep using the power button.</i> 74 * 75 * <p>In addition, you can add two more flags, which affect behavior of the screen only. <i>These 76 * flags have no effect when combined with a {@link #PARTIAL_WAKE_LOCK}.</i> 77 * <table border="2" width="85%" align="center" frame="hsides" rules="rows"> 78 * 79 * <thead> 80 * <tr><th>Flag Value</th> <th>Description</th></tr> 81 * </thead> 82 * 83 * <tbody> 84 * <tr><th>{@link #ACQUIRE_CAUSES_WAKEUP}</th> 85 * <td>Normal wake locks don't actually turn on the illumination. Instead, they cause 86 * the illumination to remain on once it turns on (e.g. from user activity). This flag 87 * will force the screen and/or keyboard to turn on immediately, when the WakeLock is 88 * acquired. A typical use would be for notifications which are important for the user to 89 * see immediately.</td> 90 * </tr> 91 * 92 * <tr><th>{@link #ON_AFTER_RELEASE}</th> 93 * <td>If this flag is set, the user activity timer will be reset when the WakeLock is 94 * released, causing the illumination to remain on a bit longer. This can be used to 95 * reduce flicker if you are cycling between wake lock conditions.</td> 96 * </tr> 97 * </tbody> 98 * </table> 99 * 100 * Any application using a WakeLock must request the {@code android.permission.WAKE_LOCK} 101 * permission in an {@code <uses-permission>} element of the application's manifest. 102 */ 103public class PowerManager 104{ 105 private static final String TAG = "PowerManager"; 106 107 /** 108 * These internal values define the underlying power elements that we might 109 * want to control individually. Eventually we'd like to expose them. 110 */ 111 private static final int WAKE_BIT_CPU_STRONG = 1; 112 private static final int WAKE_BIT_CPU_WEAK = 2; 113 private static final int WAKE_BIT_SCREEN_DIM = 4; 114 private static final int WAKE_BIT_SCREEN_BRIGHT = 8; 115 private static final int WAKE_BIT_KEYBOARD_BRIGHT = 16; 116 private static final int WAKE_BIT_PROXIMITY_SCREEN_OFF = 32; 117 118 private static final int LOCK_MASK = WAKE_BIT_CPU_STRONG 119 | WAKE_BIT_CPU_WEAK 120 | WAKE_BIT_SCREEN_DIM 121 | WAKE_BIT_SCREEN_BRIGHT 122 | WAKE_BIT_KEYBOARD_BRIGHT 123 | WAKE_BIT_PROXIMITY_SCREEN_OFF; 124 125 /** 126 * Wake lock that ensures that the CPU is running. The screen might 127 * not be on. 128 */ 129 public static final int PARTIAL_WAKE_LOCK = WAKE_BIT_CPU_STRONG; 130 131 /** 132 * Wake lock that ensures that the screen and keyboard are on at 133 * full brightness. 134 */ 135 public static final int FULL_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_BRIGHT 136 | WAKE_BIT_KEYBOARD_BRIGHT; 137 138 /** 139 * Wake lock that ensures that the screen is on at full brightness; 140 * the keyboard backlight will be allowed to go off. 141 */ 142 public static final int SCREEN_BRIGHT_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_BRIGHT; 143 144 /** 145 * Wake lock that ensures that the screen is on (but may be dimmed); 146 * the keyboard backlight will be allowed to go off. 147 */ 148 public static final int SCREEN_DIM_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_DIM; 149 150 /** 151 * Wake lock that turns the screen off when the proximity sensor activates. 152 * Since not all devices have proximity sensors, use 153 * {@link #getSupportedWakeLockFlags() getSupportedWakeLockFlags()} to determine if 154 * this wake lock mode is supported. 155 * 156 * {@hide} 157 */ 158 public static final int PROXIMITY_SCREEN_OFF_WAKE_LOCK = WAKE_BIT_PROXIMITY_SCREEN_OFF; 159 160 /** 161 * Flag for {@link WakeLock#release release(int)} to defer releasing a 162 * {@link #WAKE_BIT_PROXIMITY_SCREEN_OFF} wakelock until the proximity sensor returns 163 * a negative value. 164 * 165 * {@hide} 166 */ 167 public static final int WAIT_FOR_PROXIMITY_NEGATIVE = 1; 168 169 /** 170 * Normally wake locks don't actually wake the device, they just cause 171 * it to remain on once it's already on. Think of the video player 172 * app as the normal behavior. Notifications that pop up and want 173 * the device to be on are the exception; use this flag to be like them. 174 * <p> 175 * Does not work with PARTIAL_WAKE_LOCKs. 176 */ 177 public static final int ACQUIRE_CAUSES_WAKEUP = 0x10000000; 178 179 /** 180 * When this wake lock is released, poke the user activity timer 181 * so the screen stays on for a little longer. 182 * <p> 183 * Will not turn the screen on if it is not already on. See {@link #ACQUIRE_CAUSES_WAKEUP} 184 * if you want that. 185 * <p> 186 * Does not work with PARTIAL_WAKE_LOCKs. 187 */ 188 public static final int ON_AFTER_RELEASE = 0x20000000; 189 190 /** 191 * Class lets you say that you need to have the device on. 192 * <p> 193 * Call release when you are done and don't need the lock anymore. 194 * <p> 195 * Any application using a WakeLock must request the {@code android.permission.WAKE_LOCK} 196 * permission in an {@code <uses-permission>} element of the application's manifest. 197 */ 198 public class WakeLock 199 { 200 static final int RELEASE_WAKE_LOCK = 1; 201 202 Runnable mReleaser = new Runnable() { 203 public void run() { 204 release(); 205 } 206 }; 207 208 int mFlags; 209 String mTag; 210 IBinder mToken; 211 int mCount = 0; 212 boolean mRefCounted = true; 213 boolean mHeld = false; 214 WorkSource mWorkSource; 215 216 WakeLock(int flags, String tag) 217 { 218 switch (flags & LOCK_MASK) { 219 case PARTIAL_WAKE_LOCK: 220 case SCREEN_DIM_WAKE_LOCK: 221 case SCREEN_BRIGHT_WAKE_LOCK: 222 case FULL_WAKE_LOCK: 223 case PROXIMITY_SCREEN_OFF_WAKE_LOCK: 224 break; 225 default: 226 throw new IllegalArgumentException(); 227 } 228 229 mFlags = flags; 230 mTag = tag; 231 mToken = new Binder(); 232 } 233 234 /** 235 * Sets whether this WakeLock is ref counted. 236 * 237 * <p>Wake locks are reference counted by default. 238 * 239 * @param value true for ref counted, false for not ref counted. 240 */ 241 public void setReferenceCounted(boolean value) 242 { 243 mRefCounted = value; 244 } 245 246 /** 247 * Makes sure the device is on at the level you asked when you created 248 * the wake lock. 249 */ 250 public void acquire() 251 { 252 synchronized (mToken) { 253 if (!mRefCounted || mCount++ == 0) { 254 try { 255 mService.acquireWakeLock(mFlags, mToken, mTag, mWorkSource); 256 } catch (RemoteException e) { 257 } 258 mHeld = true; 259 } 260 } 261 } 262 263 /** 264 * Makes sure the device is on at the level you asked when you created 265 * the wake lock. The lock will be released after the given timeout. 266 * 267 * @param timeout Release the lock after the give timeout in milliseconds. 268 */ 269 public void acquire(long timeout) { 270 acquire(); 271 mHandler.postDelayed(mReleaser, timeout); 272 } 273 274 275 /** 276 * Release your claim to the CPU or screen being on. 277 * 278 * <p> 279 * It may turn off shortly after you release it, or it may not if there 280 * are other wake locks held. 281 */ 282 public void release() 283 { 284 release(0); 285 } 286 287 /** 288 * Release your claim to the CPU or screen being on. 289 * @param flags Combination of flag values to modify the release behavior. 290 * Currently only {@link #WAIT_FOR_PROXIMITY_NEGATIVE} is supported. 291 * 292 * <p> 293 * It may turn off shortly after you release it, or it may not if there 294 * are other wake locks held. 295 * 296 * {@hide} 297 */ 298 public void release(int flags) 299 { 300 synchronized (mToken) { 301 if (!mRefCounted || --mCount == 0) { 302 try { 303 mService.releaseWakeLock(mToken, flags); 304 } catch (RemoteException e) { 305 } 306 mHeld = false; 307 } 308 if (mCount < 0) { 309 throw new RuntimeException("WakeLock under-locked " + mTag); 310 } 311 } 312 } 313 314 public boolean isHeld() 315 { 316 synchronized (mToken) { 317 return mHeld; 318 } 319 } 320 321 public void setWorkSource(WorkSource ws) { 322 synchronized (mToken) { 323 if (ws != null && ws.size() == 0) { 324 ws = null; 325 } 326 boolean changed = true; 327 if (ws == null) { 328 mWorkSource = null; 329 } else if (mWorkSource == null) { 330 changed = mWorkSource != null; 331 mWorkSource = new WorkSource(ws); 332 } else { 333 changed = mWorkSource.diff(ws); 334 if (changed) { 335 mWorkSource.set(ws); 336 } 337 } 338 if (changed && mHeld) { 339 try { 340 mService.updateWakeLockWorkSource(mToken, mWorkSource); 341 } catch (RemoteException e) { 342 } 343 } 344 } 345 } 346 347 public String toString() { 348 synchronized (mToken) { 349 return "WakeLock{" 350 + Integer.toHexString(System.identityHashCode(this)) 351 + " held=" + mHeld + ", refCount=" + mCount + "}"; 352 } 353 } 354 355 @Override 356 protected void finalize() throws Throwable 357 { 358 synchronized (mToken) { 359 if (mHeld) { 360 Log.wtf(TAG, "WakeLock finalized while still held: " + mTag); 361 try { 362 mService.releaseWakeLock(mToken, 0); 363 } catch (RemoteException e) { 364 } 365 } 366 } 367 } 368 } 369 370 /** 371 * Get a wake lock at the level of the flags parameter. Call 372 * {@link WakeLock#acquire() acquire()} on the object to acquire the 373 * wake lock, and {@link WakeLock#release release()} when you are done. 374 * 375 * {@samplecode 376 *PowerManager pm = (PowerManager)mContext.getSystemService( 377 * Context.POWER_SERVICE); 378 *PowerManager.WakeLock wl = pm.newWakeLock( 379 * PowerManager.SCREEN_DIM_WAKE_LOCK 380 * | PowerManager.ON_AFTER_RELEASE, 381 * TAG); 382 *wl.acquire(); 383 * // ... 384 *wl.release(); 385 * } 386 * 387 * @param flags Combination of flag values defining the requested behavior of the WakeLock. 388 * @param tag Your class name (or other tag) for debugging purposes. 389 * 390 * @see WakeLock#acquire() 391 * @see WakeLock#release() 392 */ 393 public WakeLock newWakeLock(int flags, String tag) 394 { 395 if (tag == null) { 396 throw new NullPointerException("tag is null in PowerManager.newWakeLock"); 397 } 398 return new WakeLock(flags, tag); 399 } 400 401 /** 402 * User activity happened. 403 * <p> 404 * Turns the device from whatever state it's in to full on, and resets 405 * the auto-off timer. 406 * 407 * @param when is used to order this correctly with the wake lock calls. 408 * This time should be in the {@link SystemClock#uptimeMillis 409 * SystemClock.uptimeMillis()} time base. 410 * @param noChangeLights should be true if you don't want the lights to 411 * turn on because of this event. This is set when the power 412 * key goes down. We want the device to stay on while the button 413 * is down, but we're about to turn off. Otherwise the lights 414 * flash on and then off and it looks weird. 415 */ 416 public void userActivity(long when, boolean noChangeLights) 417 { 418 try { 419 mService.userActivity(when, noChangeLights); 420 } catch (RemoteException e) { 421 } 422 } 423 424 /** 425 * Force the device to go to sleep. Overrides all the wake locks that are 426 * held. 427 * 428 * @param time is used to order this correctly with the wake lock calls. 429 * The time should be in the {@link SystemClock#uptimeMillis 430 * SystemClock.uptimeMillis()} time base. 431 */ 432 public void goToSleep(long time) 433 { 434 try { 435 mService.goToSleep(time); 436 } catch (RemoteException e) { 437 } 438 } 439 440 /** 441 * sets the brightness of the backlights (screen, keyboard, button). 442 * 443 * @param brightness value from 0 to 255 444 * 445 * {@hide} 446 */ 447 public void setBacklightBrightness(int brightness) 448 { 449 try { 450 mService.setBacklightBrightness(brightness); 451 } catch (RemoteException e) { 452 } 453 } 454 455 /** 456 * Returns the set of flags for {@link #newWakeLock(int, String) newWakeLock()} 457 * that are supported on the device. 458 * For example, to test to see if the {@link #PROXIMITY_SCREEN_OFF_WAKE_LOCK} 459 * is supported: 460 * 461 * {@samplecode 462 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 463 * int supportedFlags = pm.getSupportedWakeLockFlags(); 464 * boolean proximitySupported = ((supportedFlags & PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK) 465 * == PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK); 466 * } 467 * 468 * @return the set of supported WakeLock flags. 469 * 470 * {@hide} 471 */ 472 public int getSupportedWakeLockFlags() 473 { 474 try { 475 return mService.getSupportedWakeLockFlags(); 476 } catch (RemoteException e) { 477 return 0; 478 } 479 } 480 481 /** 482 * Returns whether the screen is currently on. The screen could be bright 483 * or dim. 484 * 485 * {@samplecode 486 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 487 * boolean isScreenOn = pm.isScreenOn(); 488 * } 489 * 490 * @return whether the screen is on (bright or dim). 491 */ 492 public boolean isScreenOn() 493 { 494 try { 495 return mService.isScreenOn(); 496 } catch (RemoteException e) { 497 return false; 498 } 499 } 500 501 /** 502 * Reboot the device. Will not return if the reboot is 503 * successful. Requires the {@link android.Manifest.permission#REBOOT} 504 * permission. 505 * 506 * @param reason code to pass to the kernel (e.g., "recovery") to 507 * request special boot modes, or null. 508 */ 509 public void reboot(String reason) 510 { 511 try { 512 mService.reboot(reason); 513 } catch (RemoteException e) { 514 } 515 } 516 517 private PowerManager() 518 { 519 } 520 521 /** 522 * {@hide} 523 */ 524 public PowerManager(IPowerManager service, Handler handler) 525 { 526 mService = service; 527 mHandler = handler; 528 } 529 530 /** 531 * TODO: It would be nice to be able to set the poke lock here, 532 * but I'm not sure what would be acceptable as an interface - 533 * either a PokeLock object (like WakeLock) or, possibly just a 534 * method call to set the poke lock. 535 */ 536 537 IPowerManager mService; 538 Handler mHandler; 539} 540