android：靠近脸部时关闭屏幕

Question

我的应用程序允许用户访问他们的公司语音邮件。通常，在通话过程中，当用户将设备放在耳边时，屏幕会关闭，这样他们就不会意外地用脸按下按钮。我想让我的应用程序在用户收听语音邮件时执行相同的操作。

有人知道该怎么做吗？

Answer 1

如果允许您查看开源代码而不会给自己带来问题，请检查 的源代码Android 手机应用程序。具体来说 src/com/android/phone/PhoneApp.java 和 src/com/android/phone/InCallScreen.java。

来自 src/com/android/phone/PhoneApp.java：

 //Around line 519
 // Wake lock used to control proximity sensor behavior.
 if ((pm.getSupportedWakeLockFlags()
          & PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK) != 0x0) {
     mProximityWakeLock = pm.newWakeLock(
         PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK,
         LOG_TAG);
 }

 ....
// Around line 1334
if (((state == Phone.State.OFFHOOK) || mBeginningCall)&& !screenOnImmediately) {
  // Phone is in use!  Arrange for the screen to turn off
  // automatically when the sensor detects a close object.
  if (!mProximityWakeLock.isHeld()) {
      if (DBG) Log.d(LOG_TAG, "updateProximitySensorMode: acquiring...");
      mProximityWakeLock.acquire();
  } else {
      if (VDBG) Log.d(LOG_TAG, "updateProximitySensorMode: lock already held.");
  }
} else {
  // Phone is either idle, or ringing.  We don't want any
  // special proximity sensor behavior in either case.
  if (mProximityWakeLock.isHeld()) {
    if (DBG) Log.d(LOG_TAG, "updateProximitySensorMode: releasing...");
    // Wait until user has moved the phone away from his head if we are
    // releasing due to the phone call ending.
    // Qtherwise, turn screen on immediately
    int flags =
        (screenOnImmediately ? 0 : PowerManager.WAIT_FOR_PROXIMITY_NEGATIVE);
    mProximityWakeLock.release(flags);
  }
}

此外，如果您查看 PowerManager 类的代码，PROXIMITY_SCREEN_OFF_WAKE_LOCK 已记录（但隐藏）并且应该执行您想要的操作（我不确定这适用于哪个 API 级别） ，但是）——但由于某种原因不在表中。

/**
 * Wake lock that turns the screen off when the proximity sensor activates.
 * Since not all devices have proximity sensors, use
 * {@link #getSupportedWakeLockFlags() getSupportedWakeLockFlags()} to determine if
 * this wake lock mode is supported.
 *
 * {@hide}
 */
public static final int PROXIMITY_SCREEN_OFF_WAKE_LOCK = WAKE_BIT_PROXIMITY_SCREEN_OFF;

如果您不害怕使用潜在的未记录功能，那么它应该完全满足您的需要。

Answer 2

从 API 级别 21 (Lollipop) 开始，您可以获得邻近唤醒锁，就像这样：

if(powerManager.isWakeLockLevelSupported(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK)) {
        PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, TAG);
        wakeLock.setReferenceCounted(false);
        return wakeLock;
    } else {
        return null;
    }
}

然后由您来获取和释放锁。

PS：PowerManager#getSupportedWakeLockFlags 曾被隐藏，但现在不再存在。他们发明了 isWakeLockLevelSupported。

Answer 3

您所看到的是接近传感器的使用。对于具有该功能的设备，您可以通过 SensorManager 访问它。

Answer 4

也许您不再需要它，但对于那些对代码感兴趣的人，您可以查看我的SpeakerProximity项目，网址为http://code.google.com/p/speakerproximity/