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 17 package android.os; 18 19 import 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 */ 103 public 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 * <p class="note">Most applications should strongly consider using 136 * {@link android.view.WindowManager.LayoutParams#FLAG_KEEP_SCREEN_ON}. 137 * This window flag will be correctly managed by the platform 138 * as the user moves between applications and doesn't require a special permission.</p> 139 */ 140 public static final int FULL_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_BRIGHT 141 | WAKE_BIT_KEYBOARD_BRIGHT; 142 143 /** 144 * @deprecated Most applications should use 145 * {@link android.view.WindowManager.LayoutParams#FLAG_KEEP_SCREEN_ON} instead 146 * of this type of wake lock, as it will be correctly managed by the platform 147 * as the user moves between applications and doesn't require a special permission. 148 * 149 * Wake lock that ensures that the screen is on at full brightness; 150 * the keyboard backlight will be allowed to go off. 151 */ 152 @Deprecated 153 public static final int SCREEN_BRIGHT_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_BRIGHT; 154 155 /** 156 * Wake lock that ensures that the screen is on (but may be dimmed); 157 * the keyboard backlight will be allowed to go off. 158 */ 159 public static final int SCREEN_DIM_WAKE_LOCK = WAKE_BIT_CPU_WEAK | WAKE_BIT_SCREEN_DIM; 160 161 /** 162 * Wake lock that turns the screen off when the proximity sensor activates. 163 * Since not all devices have proximity sensors, use 164 * {@link #getSupportedWakeLockFlags() getSupportedWakeLockFlags()} to determine if 165 * this wake lock mode is supported. 166 * 167 * {@hide} 168 */ 169 public static final int PROXIMITY_SCREEN_OFF_WAKE_LOCK = WAKE_BIT_PROXIMITY_SCREEN_OFF; 170 171 /** 172 * Flag for {@link WakeLock#release release(int)} to defer releasing a 173 * {@link #WAKE_BIT_PROXIMITY_SCREEN_OFF} wakelock until the proximity sensor returns 174 * a negative value. 175 * 176 * {@hide} 177 */ 178 public static final int WAIT_FOR_PROXIMITY_NEGATIVE = 1; 179 180 /** 181 * Normally wake locks don't actually wake the device, they just cause 182 * it to remain on once it's already on. Think of the video player 183 * app as the normal behavior. Notifications that pop up and want 184 * the device to be on are the exception; use this flag to be like them. 185 * <p> 186 * Does not work with PARTIAL_WAKE_LOCKs. 187 */ 188 public static final int ACQUIRE_CAUSES_WAKEUP = 0x10000000; 189 190 /** 191 * When this wake lock is released, poke the user activity timer 192 * so the screen stays on for a little longer. 193 * <p> 194 * Will not turn the screen on if it is not already on. See {@link #ACQUIRE_CAUSES_WAKEUP} 195 * if you want that. 196 * <p> 197 * Does not work with PARTIAL_WAKE_LOCKs. 198 */ 199 public static final int ON_AFTER_RELEASE = 0x20000000; 200 201 /** 202 * Class lets you say that you need to have the device on. 203 * <p> 204 * Call release when you are done and don't need the lock anymore. 205 * <p> 206 * Any application using a WakeLock must request the {@code android.permission.WAKE_LOCK} 207 * permission in an {@code <uses-permission>} element of the application's manifest. 208 */ 209 public class WakeLock 210 { 211 static final int RELEASE_WAKE_LOCK = 1; 212 213 Runnable mReleaser = new Runnable() { 214 public void run() { 215 release(); 216 } 217 }; 218 219 int mFlags; 220 String mTag; 221 IBinder mToken; 222 int mCount = 0; 223 boolean mRefCounted = true; 224 boolean mHeld = false; 225 WorkSource mWorkSource; 226 WakeLock(int flags, String tag)227 WakeLock(int flags, String tag) 228 { 229 switch (flags & LOCK_MASK) { 230 case PARTIAL_WAKE_LOCK: 231 case SCREEN_DIM_WAKE_LOCK: 232 case SCREEN_BRIGHT_WAKE_LOCK: 233 case FULL_WAKE_LOCK: 234 case PROXIMITY_SCREEN_OFF_WAKE_LOCK: 235 break; 236 default: 237 throw new IllegalArgumentException(); 238 } 239 240 mFlags = flags; 241 mTag = tag; 242 mToken = new Binder(); 243 } 244 245 /** 246 * Sets whether this WakeLock is ref counted. 247 * 248 * <p>Wake locks are reference counted by default. 249 * 250 * @param value true for ref counted, false for not ref counted. 251 */ setReferenceCounted(boolean value)252 public void setReferenceCounted(boolean value) 253 { 254 mRefCounted = value; 255 } 256 257 /** 258 * Makes sure the device is on at the level you asked when you created 259 * the wake lock. 260 */ acquire()261 public void acquire() 262 { 263 synchronized (mToken) { 264 acquireLocked(); 265 } 266 } 267 268 /** 269 * Makes sure the device is on at the level you asked when you created 270 * the wake lock. The lock will be released after the given timeout. 271 * 272 * @param timeout Release the lock after the give timeout in milliseconds. 273 */ acquire(long timeout)274 public void acquire(long timeout) { 275 synchronized (mToken) { 276 acquireLocked(); 277 mHandler.postDelayed(mReleaser, timeout); 278 } 279 } 280 acquireLocked()281 private void acquireLocked() { 282 if (!mRefCounted || mCount++ == 0) { 283 mHandler.removeCallbacks(mReleaser); 284 try { 285 mService.acquireWakeLock(mFlags, mToken, mTag, mWorkSource); 286 } catch (RemoteException e) { 287 } 288 mHeld = true; 289 } 290 } 291 292 /** 293 * Release your claim to the CPU or screen being on. 294 * 295 * <p> 296 * It may turn off shortly after you release it, or it may not if there 297 * are other wake locks held. 298 */ release()299 public void release() { 300 release(0); 301 } 302 303 /** 304 * Release your claim to the CPU or screen being on. 305 * @param flags Combination of flag values to modify the release behavior. 306 * Currently only {@link #WAIT_FOR_PROXIMITY_NEGATIVE} is supported. 307 * 308 * <p> 309 * It may turn off shortly after you release it, or it may not if there 310 * are other wake locks held. 311 * 312 * {@hide} 313 */ release(int flags)314 public void release(int flags) { 315 synchronized (mToken) { 316 if (!mRefCounted || --mCount == 0) { 317 mHandler.removeCallbacks(mReleaser); 318 try { 319 mService.releaseWakeLock(mToken, flags); 320 } catch (RemoteException e) { 321 } 322 mHeld = false; 323 } 324 if (mCount < 0) { 325 throw new RuntimeException("WakeLock under-locked " + mTag); 326 } 327 } 328 } 329 isHeld()330 public boolean isHeld() 331 { 332 synchronized (mToken) { 333 return mHeld; 334 } 335 } 336 setWorkSource(WorkSource ws)337 public void setWorkSource(WorkSource ws) { 338 synchronized (mToken) { 339 if (ws != null && ws.size() == 0) { 340 ws = null; 341 } 342 boolean changed = true; 343 if (ws == null) { 344 mWorkSource = null; 345 } else if (mWorkSource == null) { 346 changed = mWorkSource != null; 347 mWorkSource = new WorkSource(ws); 348 } else { 349 changed = mWorkSource.diff(ws); 350 if (changed) { 351 mWorkSource.set(ws); 352 } 353 } 354 if (changed && mHeld) { 355 try { 356 mService.updateWakeLockWorkSource(mToken, mWorkSource); 357 } catch (RemoteException e) { 358 } 359 } 360 } 361 } 362 toString()363 public String toString() { 364 synchronized (mToken) { 365 return "WakeLock{" 366 + Integer.toHexString(System.identityHashCode(this)) 367 + " held=" + mHeld + ", refCount=" + mCount + "}"; 368 } 369 } 370 371 @Override finalize()372 protected void finalize() throws Throwable 373 { 374 synchronized (mToken) { 375 if (mHeld) { 376 Log.wtf(TAG, "WakeLock finalized while still held: " + mTag); 377 try { 378 mService.releaseWakeLock(mToken, 0); 379 } catch (RemoteException e) { 380 } 381 } 382 } 383 } 384 } 385 386 /** 387 * Get a wake lock at the level of the flags parameter. Call 388 * {@link WakeLock#acquire() acquire()} on the object to acquire the 389 * wake lock, and {@link WakeLock#release release()} when you are done. 390 * 391 * {@samplecode 392 *PowerManager pm = (PowerManager)mContext.getSystemService( 393 * Context.POWER_SERVICE); 394 *PowerManager.WakeLock wl = pm.newWakeLock( 395 * PowerManager.SCREEN_DIM_WAKE_LOCK 396 * | PowerManager.ON_AFTER_RELEASE, 397 * TAG); 398 *wl.acquire(); 399 * // ... 400 *wl.release(); 401 * } 402 * 403 * <p class="note">If using this to keep the screen on, you should strongly consider using 404 * {@link android.view.WindowManager.LayoutParams#FLAG_KEEP_SCREEN_ON} instead. 405 * This window flag will be correctly managed by the platform 406 * as the user moves between applications and doesn't require a special permission.</p> 407 * 408 * @param flags Combination of flag values defining the requested behavior of the WakeLock. 409 * @param tag Your class name (or other tag) for debugging purposes. 410 * 411 * @see WakeLock#acquire() 412 * @see WakeLock#release() 413 */ newWakeLock(int flags, String tag)414 public WakeLock newWakeLock(int flags, String tag) 415 { 416 if (tag == null) { 417 throw new NullPointerException("tag is null in PowerManager.newWakeLock"); 418 } 419 return new WakeLock(flags, tag); 420 } 421 422 /** 423 * User activity happened. 424 * <p> 425 * Turns the device from whatever state it's in to full on, and resets 426 * the auto-off timer. 427 * 428 * @param when is used to order this correctly with the wake lock calls. 429 * This time should be in the {@link SystemClock#uptimeMillis 430 * SystemClock.uptimeMillis()} time base. 431 * @param noChangeLights should be true if you don't want the lights to 432 * turn on because of this event. This is set when the power 433 * key goes down. We want the device to stay on while the button 434 * is down, but we're about to turn off. Otherwise the lights 435 * flash on and then off and it looks weird. 436 */ userActivity(long when, boolean noChangeLights)437 public void userActivity(long when, boolean noChangeLights) 438 { 439 try { 440 mService.userActivity(when, noChangeLights); 441 } catch (RemoteException e) { 442 } 443 } 444 445 /** 446 * Force the device to go to sleep. Overrides all the wake locks that are 447 * held. 448 * 449 * @param time is used to order this correctly with the wake lock calls. 450 * The time should be in the {@link SystemClock#uptimeMillis 451 * SystemClock.uptimeMillis()} time base. 452 */ goToSleep(long time)453 public void goToSleep(long time) 454 { 455 try { 456 mService.goToSleep(time); 457 } catch (RemoteException e) { 458 } 459 } 460 461 /** 462 * sets the brightness of the backlights (screen, keyboard, button). 463 * 464 * @param brightness value from 0 to 255 465 * 466 * {@hide} 467 */ setBacklightBrightness(int brightness)468 public void setBacklightBrightness(int brightness) 469 { 470 try { 471 mService.setBacklightBrightness(brightness); 472 } catch (RemoteException e) { 473 } 474 } 475 476 /** 477 * Returns the set of flags for {@link #newWakeLock(int, String) newWakeLock()} 478 * that are supported on the device. 479 * For example, to test to see if the {@link #PROXIMITY_SCREEN_OFF_WAKE_LOCK} 480 * is supported: 481 * 482 * {@samplecode 483 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 484 * int supportedFlags = pm.getSupportedWakeLockFlags(); 485 * boolean proximitySupported = ((supportedFlags & PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK) 486 * == PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK); 487 * } 488 * 489 * @return the set of supported WakeLock flags. 490 * 491 * {@hide} 492 */ getSupportedWakeLockFlags()493 public int getSupportedWakeLockFlags() 494 { 495 try { 496 return mService.getSupportedWakeLockFlags(); 497 } catch (RemoteException e) { 498 return 0; 499 } 500 } 501 502 /** 503 * Returns whether the screen is currently on. The screen could be bright 504 * or dim. 505 * 506 * {@samplecode 507 * PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); 508 * boolean isScreenOn = pm.isScreenOn(); 509 * } 510 * 511 * @return whether the screen is on (bright or dim). 512 */ isScreenOn()513 public boolean isScreenOn() 514 { 515 try { 516 return mService.isScreenOn(); 517 } catch (RemoteException e) { 518 return false; 519 } 520 } 521 522 /** 523 * Reboot the device. Will not return if the reboot is 524 * successful. Requires the {@link android.Manifest.permission#REBOOT} 525 * permission. 526 * 527 * @param reason code to pass to the kernel (e.g., "recovery") to 528 * request special boot modes, or null. 529 */ reboot(String reason)530 public void reboot(String reason) 531 { 532 try { 533 mService.reboot(reason); 534 } catch (RemoteException e) { 535 } 536 } 537 PowerManager()538 private PowerManager() 539 { 540 } 541 542 /** 543 * {@hide} 544 */ PowerManager(IPowerManager service, Handler handler)545 public PowerManager(IPowerManager service, Handler handler) 546 { 547 mService = service; 548 mHandler = handler; 549 } 550 551 /** 552 * TODO: It would be nice to be able to set the poke lock here, 553 * but I'm not sure what would be acceptable as an interface - 554 * either a PokeLock object (like WakeLock) or, possibly just a 555 * method call to set the poke lock. 556 */ 557 558 IPowerManager mService; 559 Handler mHandler; 560 } 561