android 6.0 power按键深度解析

主要分析power按键点亮屏幕和灭屏，而且我们主要分析在PhoneWIndowManager的流程。

之前的博客我们分析过按键的流程，当有按键会先到PhoneWindowManager的interceptKeyBeforeQueueing函数，然后再去分析到应用，而power按键也是如此，并且其最后不会分发到应用中去，下面我们看下PhoneWindowManager的interceptKeyBeforeQueueing函数对power按键处理的代码：
顺便说下这个interactive这个变量是从NativeInputManager中传过来的，在NativeInputManager也是有一个mInteractive的成员变量，是PowerManagerService改变状态的时候在Notifier.Java中调用InputManagerService的Native方法，到NativeInputManager的方法nativeSetInteractive方法来设置的mInteractive变量的。所以这个值也可以说是PowerManagerService关于屏幕的状态。
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case KeyEvent.KEYCODE_POWER: {
result &= ~ACTION_PASS_TO_USER;//不分发到应用
isWakeKey = false; // wake-up will be handled separately
if (down) {
Log.i(TAG, “PowerKey down, interactive = ” + interactive);
interceptPowerKeyDown(event, interactive);//按键down
} else {
Log.i(TAG, “PowerKey up.”);
interceptPowerKeyUp(event, interactive, canceled);//按键up
}
break;
}
一、Powerkey down
我们先来看下按键down的interceptPowerKeyDown函数：
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private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {
// Hold a wake lock until the power key is released.
if (!mPowerKeyWakeLock.isHeld()) {//上层持锁
mPowerKeyWakeLock.acquire();
}

// Cancel multi-press detection timeout.  if (mPowerKeyPressCounter != 0) {//在我们的手机不支持这块，统计多次按键      mHandler.removeMessages(MSG_POWER_DELAYED_PRESS);  }  

…
if (!mPowerKeyHandled) {
if (interactive) {//亮屏
// When interactive, we’re already awake.
// Wait for a long press or for the button to be released to decide what to do.
if (hasLongPressOnPowerBehavior()) {//是否支持长按键
Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);
msg.setAsynchronous(true);
mHandler.sendMessageDelayed(msg,
ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());
}
} else {
wakeUpFromPowerKey(event.getDownTime());

        if (mSupportLongPressPowerWhenNonInteractive && hasLongPressOnPowerBehavior()) {              Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);              msg.setAsynchronous(true);              mHandler.sendMessageDelayed(msg,                      ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());              mBeganFromNonInteractive = true;          } else {              final int maxCount = getMaxMultiPressPowerCount();              if (maxCount <= 1) {                  mPowerKeyHandled = true;              } else {                  mBeganFromNonInteractive = true;              }          }      }  }  

}

1.1 亮屏 长按键处理
我们先来看看hasLongPressOnPowerBehavior函数：
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private boolean hasLongPressOnPowerBehavior() {
return getResolvedLongPressOnPowerBehavior() != LONG_PRESS_POWER_NOTHING;//不为0
}
再来看看getResolvedLongPressOnPowerBehavior函数
[cpp] view plain copy
private int getResolvedLongPressOnPowerBehavior() {
if (FactoryTest.isLongPressOnPowerOffEnabled()) {
return LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM;
}
return mLongPressOnPowerBehavior;
}
其中又调用了isLongPressOnPowerOffEnabled，我们没有支持这个属性。因此只要看mLongPressOnPowerBehavior这个变量
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public static boolean isLongPressOnPowerOffEnabled() {
return SystemProperties.getInt(“factory.long_press_power_off”, 0) != 0;
}
下面再看看mLongPressOnPowerBehavior 这个变量的初始化。
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mLongPressOnPowerBehavior = mContext.getResources().getInteger(
com.android.internal.R.integer.config_longPressOnPowerBehavior);
看资源apk：
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./res/values/config.xml:743: 1也就是mLongPressOnPowerBehavior = 1，最后hasLongPressOnPowerBehavior返回1.
[cpp] view plain copy
if (hasLongPressOnPowerBehavior()) {
Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);
msg.setAsynchronous(true);
mHandler.sendMessageDelayed(msg,
ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());
}
然后就发消息，我们再来看处理消息：
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case MSG_POWER_LONG_PRESS:
powerLongPress();
再来看powerLongPress函数
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private void powerLongPress() {
final int behavior = getResolvedLongPressOnPowerBehavior();
switch (behavior) {
case LONG_PRESS_POWER_NOTHING:
break;
case LONG_PRESS_POWER_GLOBAL_ACTIONS://返回1
mPowerKeyHandled = true;
if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
performAuditoryFeedbackForAccessibilityIfNeed();
}
showGlobalActionsInternal();//下面就是弹出关机，重启之类的对话框了
break;
上面之前我们再添加长按对话框添加重启功能的那篇博客有涉及，这就是在亮屏的时候长按power的流程。

1.2 灭屏 按键down处理
下面我们再来看看，interceptPowerKeyDown的另一个分支，关于现在是灭屏的时候，按键down。
[cpp] view plain copy
else {//灭屏
wakeUpFromPowerKey(event.getDownTime());//亮屏

  if (mSupportLongPressPowerWhenNonInteractive && hasLongPressOnPowerBehavior()) {        Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);        msg.setAsynchronous(true);        mHandler.sendMessageDelayed(msg,                ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());        mBeganFromNonInteractive = true;    } else {        final int maxCount = getMaxMultiPressPowerCount();        if (maxCount <= 1) {            mPowerKeyHandled = true;        } else {            mBeganFromNonInteractive = true;        }    }  

第一步直接调用wakeUpFromPowerKey函数，我们看下这个函数：
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private void wakeUpFromPowerKey(long eventTime) {
wakeUp(eventTime, mAllowTheaterModeWakeFromPowerKey, “android.policy:POWER”);//这里mAllowTheaterModeWakeFromPowerKey为true
}

private boolean wakeUp(long wakeTime, boolean wakeInTheaterMode, String reason) {
final boolean theaterModeEnabled = isTheaterModeEnabled();
if (!wakeInTheaterMode && theaterModeEnabled) {
return false;
}

if (theaterModeEnabled) {      Settings.Global.putInt(mContext.getContentResolver(),              Settings.Global.THEATER_MODE_ON, 0);  }  mPolicyLooper.setMessageLogging(mLogPrinter);  mPowerManager.wakeUp(wakeTime, reason);  return true;  

}
这里mAllowTheaterModeWakeFromPowerKey为true，因此就直接调用了PowerManager的wakeUp函数了，reason是”Android.policy:POWER”

[cpp] view plain copy
else {//灭屏
wakeUpFromPowerKey(event.getDownTime());//亮屏

  if (mSupportLongPressPowerWhenNonInteractive && hasLongPressOnPowerBehavior()) {        Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);        msg.setAsynchronous(true);        mHandler.sendMessageDelayed(msg,                ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());        mBeganFromNonInteractive = true;    } else {        final int maxCount = getMaxMultiPressPowerCount();//返回为1，不支持多次按钮        if (maxCount <= 1) {            mPowerKeyHandled = true;//走这里        } else {            mBeganFromNonInteractive = true;        }    }  

而下面mSupportLongPressPowerWhenNonInteractive 我们配置也是false不支持。多按钮也不支持，因此maxCount为1

二、PowerKey On
PowerKey on 又分为之前down的时候是灭屏还是亮屏处理的，逻辑又不一样。

2.1 之前power按键 down是灭屏的
我们先来看之前Power按键 down的时候手机是灭屏的情况下，下面我们分析PowerKey on的interceptPowerKeyUp函数：
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private void interceptPowerKeyUp(KeyEvent event, boolean interactive, boolean canceled) {
final boolean handled = canceled || mPowerKeyHandled;//记得之前灭屏按键down的时候，mPowerKeyHandled = true
mScreenshotChordPowerKeyTriggered = false;
cancelPendingScreenshotChordAction();
cancelPendingPowerKeyAction();

if (!handled) {      // Figure out how to handle the key now that it has been released.      mPowerKeyPressCounter += 1;      final int maxCount = getMaxMultiPressPowerCount();      final long eventTime = event.getDownTime();      if (mPowerKeyPressCounter < maxCount) {          // This could be a multi-press.  Wait a little bit longer to confirm.          // Continue holding the wake lock.          Message msg = mHandler.obtainMessage(MSG_POWER_DELAYED_PRESS,                  interactive ? 1 : 0, mPowerKeyPressCounter, eventTime);          msg.setAsynchronous(true);          mHandler.sendMessageDelayed(msg, ViewConfiguration.getDoubleTapTimeout());          return;      }      // No other actions.  Handle it immediately.      powerPress(eventTime, interactive, mPowerKeyPressCounter);  }  // Done.  Reset our state.  finishPowerKeyPress();  

}
之前在手机灭屏我们按power键down的时候，最后mPowerKeyHandled = true，这里handled = true，最后直接调用
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private void finishPowerKeyPress() {
mBeganFromNonInteractive = false;//我们手机不支持
mPowerKeyPressCounter = 0;//多按键，不支持
if (mPowerKeyWakeLock.isHeld()) {
mPowerKeyWakeLock.release();//之前按power键down时候的锁释放
}
}

2.2 之前power按键 down是亮屏的
之前power按键 down的时候手机亮屏，power down又分为长按和短按。我们先来看之前power down亮屏，down是长按的情况下，现在是power up的情况：
[cpp] view plain copy
private void powerLongPress() {
final int behavior = getResolvedLongPressOnPowerBehavior();
switch (behavior) {
case LONG_PRESS_POWER_NOTHING:
break;
case LONG_PRESS_POWER_GLOBAL_ACTIONS://为1
mPowerKeyHandled = true;
if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
performAuditoryFeedbackForAccessibilityIfNeed();
}
showGlobalActionsInternal();
break;
case LONG_PRESS_POWER_SHUT_OFF:
case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:
mPowerKeyHandled = true;
performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);
break;
}
}
之前看过这函数，长按mPowerKeyHandled = true，和上面一样。直接最后interceptPowerKeyUp函数就调用finishPowerKeyPress函数了。

然后我们再来看之前powerKey Down的时候是亮屏的，又是短按的情况，我们再来看interceptPowerKeyUp函数：
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private void interceptPowerKeyUp(KeyEvent event, boolean interactive, boolean canceled) {
final boolean handled = canceled || mPowerKeyHandled;//这个实收handled为false了
mScreenshotChordPowerKeyTriggered = false;
cancelPendingScreenshotChordAction();
cancelPendingPowerKeyAction();

if (!handled) {      // Figure out how to handle the key now that it has been released.      mPowerKeyPressCounter += 1;      final int maxCount = getMaxMultiPressPowerCount();//这个返回为1，本来是多次按钮的。这里没有配置      final long eventTime = event.getDownTime();      if (mPowerKeyPressCounter < maxCount) {          // This could be a multi-press.  Wait a little bit longer to confirm.          // Continue holding the wake lock.          Message msg = mHandler.obtainMessage(MSG_POWER_DELAYED_PRESS,                  interactive ? 1 : 0, mPowerKeyPressCounter, eventTime);          msg.setAsynchronous(true);          mHandler.sendMessageDelayed(msg, ViewConfiguration.getDoubleTapTimeout());          return;      }      // No other actions.  Handle it immediately.      powerPress(eventTime, interactive, mPowerKeyPressCounter);  }  // Done.  Reset our state.  finishPowerKeyPress();  

}
我们先看看getMaxMultiPressPowerCount函数：
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private int getMaxMultiPressPowerCount() {
if (mTriplePressOnPowerBehavior != MULTI_PRESS_POWER_NOTHING) {// 为0
return 3;
}
if (mDoublePressOnPowerBehavior != MULTI_PRESS_POWER_NOTHING) {//为0
return 2;
}
return 1;
}
最后这个函数返回为1，因此上面函数就直接调用powerPress函数了。
[cpp] view plain copy
private void powerPress(long eventTime, boolean interactive, int count) {
if (mScreenOnEarly && !mScreenOnFully) {
Slog.i(TAG, “Suppressed redundant power key press while ”
+ “already in the process of turning the screen on.”);
return;
}

if (count == 2) {      powerMultiPressAction(eventTime, interactive, mDoublePressOnPowerBehavior);  } else if (count == 3) {      powerMultiPressAction(eventTime, interactive, mTriplePressOnPowerBehavior);  } else if (interactive && !mBeganFromNonInteractive) {//之前我们只支持1，必须亮屏，另一个参数这里为false      switch (mShortPressOnPowerBehavior) {// 这个参数也是资源apk中配置的，为1          case SHORT_PRESS_POWER_NOTHING:              break;          case SHORT_PRESS_POWER_GO_TO_SLEEP://直接调用PowerManager的goToSleep函数了              mPowerManager.goToSleep(eventTime,                      PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON, 0);              break;          case SHORT_PRESS_POWER_REALLY_GO_TO_SLEEP:              mPowerManager.goToSleep(eventTime,                      PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON,                      PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE);              break;          case SHORT_PRESS_POWER_REALLY_GO_TO_SLEEP_AND_GO_HOME:              mPowerManager.goToSleep(eventTime,                      PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON,                      PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE);              launchHomeFromHotKey();              break;          case SHORT_PRESS_POWER_GO_HOME:              launchHomeFromHotKey(true /* awakenFromDreams */, false /*respectKeyguard*/);              break;      }  }  

}
因为我们没有配置多次power按钮，mShortPressOnPowerBehavior配置为1，所以就直接调用了PowerManager的goToSleep函数了。

三、总结
这篇博客我们主要分析了，power按键在PhoneWindowManager的处理。
power按键down：
1.down又分长按亮屏 弹出关闭重启对话框
2. 短按灭屏 调用wakeup
power按键on：
1.之前down的时候亮屏短按才会调用goToSleep
2.之前down的时候亮屏长按不作处理
3.之前down的时候灭屏不作处理