Android O关机流程
问题起因
*今天测试提出了一个问题，关机过程中（播放关机动画)按Power键可以熄屏、亮屏。
解决方案
*首先我想应该从关机流程开始吧，然后自己一步步跟进代码，修改framework代码逻辑，在关机时，禁用Power键
关机流程
想必都很清楚正常关机是如何操作的，按Power键来确定关机，这里首先来分析一下PhoneWindowManager这个类，这个类Power、volum等事件处理
PhoneWindowManager.java
public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {
...
switch (keyCode) {
...
case KeyEvent.KEYCODE_POWER: {
// Any activity on the power button stops the accessibility shortcut
cancelPendingAccessibilityShortcutAction();
result &= ~ACTION_PASS_TO_USER;
isWakeKey = false; // wake-up will be handled separately
if (down) {
interceptPowerKeyDown(event, interactive);
} else {
interceptPowerKeyUp(event, interactive, canceled);
}
break;
}
...
}
}
因为是按下Power走的interceptPowerKeyDown这个函数。
private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {
...
if (!mPowerKeyHandled) {
if (interactive) {
// 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()) {
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;
}
}
}
}
}
直接看关键部分,判断是否是LongPress，是的话就通过Handler发送消息处理，追踪到mHandler，handlemessage里面调用powerLongPress()这个私有函数来处理长按power。
private void powerLongPress() {
final int behavior = getResolvedLongPressOnPowerBehavior();
switch (behavior) {
case LONG_PRESS_POWER_NOTHING:
break;
case LONG_PRESS_POWER_GLOBAL_ACTIONS:
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;
}
}
将mPowerKeyHandled设置为true表示这个行为已经被处理了，其实是正在处理。showGlobalActionsInternal()这个函数我想应该就是处理长按power显示的对话框吧。
void showGlobalActionsInternal() {
sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
if (mGlobalActions == null) {
mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);
}
final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();
mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned());
if (keyguardShowing) {
// since it took two seconds of long press to bring this up,
// poke the wake lock so they have some time to see the dialog.
mPowerManager.userActivity(SystemClock.uptimeMillis(), false);
}
}
果不其然，创建了GlobalActions类对象，而从注释该类介绍来看是一个创建全局对话框的帮助类，构造方法中获得各种系统服务，其中有AudioManager、WindowManagerFuncs，其中关机我们应该看的是WindowManagerFuncs这个服务，他获取的是WindowManagerService。再来看showDialog这个方法。
public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {
mKeyguardShowing = keyguardShowing;
mDeviceProvisioned = isDeviceProvisioned;
if (mDialog != null) {
mDialog.dismiss();
mDialog = null;
// Show delayed, so that the dismiss of the previous dialog completes
mHandler.sendEmptyMessage(MESSAGE_SHOW);
} else {
handleShow();
}
}
private GlobalActionsDialog createDialog() {
...
if (GLOBAL_ACTION_KEY_POWER.equals(actionKey)) {
mItems.add(new PowerAction());
} else if (GLOBAL_ACTION_KEY_REBOOT.equals(actionKey)) {
mItems.add(new RebootAction());
}
...
}
其中handleShow方法最终调用createDialog();这个方法来创建GlobalActionsDialog这个对话框对象，其中利用各种参数Action来控制item的各种行为，我们这里要看的就是PowerAction
private final class PowerAction extends SinglePressAction implements LongPressAction {
...
@Override
public void onPress() {
mWindowManagerFuncs.shutdown(true/* confirm */);
}
}
看到这里就都明白了，通过对话框关机，这里调用的是mWindowManagerFuncs.shutdown，这个方法，这里mWindowManagerFuncs也就是WindowManagerService这个服务
@Override
public void shutdown(boolean confirm) {
ShutdownThread.shutdown(mContext, PowerManager.SHUTDOWN_USER_REQUESTED, confirm);
}
其中通过名字可以知道调用了一个关机线程来处理，简单点的话就可以直接追踪到run方法。这里就不知道看代码了，通过打印信息来看看做了什么
11-18 20:00:17.061 1361-5920/system_process I/ShutdownThread: Sending shutdown broadcast...
11-18 20:00:18.710 1361-5920/system_process I/ShutdownThread: Shutting down activity manager...
11-18 20:00:18.913 1361-5920/system_process I/ShutdownThread: Shutting down package manager...
11-18 20:00:18.937 1361-6051/system_process W/ShutdownThread: Turning off cellular radios...
11-18 20:00:18.953 1361-6051/system_process I/ShutdownThread: Waiting for NFC, Bluetooth and Radio...
11-18 20:00:19.455 1361-6051/system_process I/ShutdownThread: Radio turned off.
11-18 20:00:19.455 1361-6051/system_process I/ShutdownThread: NFC, Radio and Bluetooth shutdown complete.
11-18 20:00:19.459 1361-5920/system_process I/ShutdownThread: Shutting down MountService
11-18 20:00:20.461 1361-5920/system_process W/ShutdownThread: Shutdown wait timed out
11-18 20:00:20.504 1361-5920/system_process I/ShutdownThread: waitShutdownAnimation true
11-18 20:00:20.510 1361-5920/system_process I/ShutdownThread: wait SHUTDOWN_ANIMATION_SERVICE completed. time out 14
11-18 20:00:20.836 1361-1712/system_process W/ShutdownThread: Result code 0 from MountService.shutdown
11-18 20:00:21.510 1361-5920/system_process I/ShutdownThread: wait SHUTDOWN_ANIMATION_SERVICE completed. time out 13
11-18 20:00:22.511 1361-5920/system_process I/ShutdownThread: wait SHUTDOWN_ANIMATION_SERVICE completed. time out 12
11-18 20:00:23.511 1361-5920/system_process I/ShutdownThread: wait SHUTDOWN_ANIMATION_SERVICE completed. time out 11
11-18 20:00:24.512 1361-5920/system_process I/ShutdownThread: wait SHUTDOWN_ANIMATION_SERVICE completed. time out 10
11-18 20:00:26.014 1361-5920/system_process I/ShutdownThread: Performing low-level shutdown...
首先发送关机广播，关闭一系列服务AMS、PKMS、radio、NFC等等等，等待关机动画完成。
- 流程理清楚了，解决起来就很简单了，在ShutdownThread设置一个静态成员变量 public static boolean isShutDowning = false; ，执行run方法就将这个标示设为true
- 然后在PhoneWindowManager的powerPress函数中添加判断是否禁用Power。
验证了也确实OK
