android：靠近脸时关闭屏幕

Question

我的应用允许用户访问他们的公司语音邮件。通常，在打电话时，当用户将设备放在耳边时，屏幕会关闭，这样他们就不会不小心用脸按下按钮。我想让我的应用在用户收听他们的语音邮件时做同样的事情。

有人知道怎么做吗？

Answer 1

如果允许您查看开源代码而不会给自己造成问题，请检查Android Phone Application 的来源。特别是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（但是我不确定这适用于哪个 API 级别）——但不在表中出于某种原因。

/**
 * 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，它应该完全满足您的需要。

Answer 2

从 API 级别 21 (Lollipop) 开始，您可以像这样获得接近唤醒锁定：

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;
    }
}

那么由你来获取和释放锁。

PS：PowerManager#getSupportedWakeLockFlags 被隐藏了，但现在已经不存在了。他们发明了isWakeLockLevelSupported。

Answer 3

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

Answer 4

您看到的是接近传感器的使用。对于拥有一台的设备，您可以通过SensorManager 访问它。