Android L使用adb命令获取FocusedApp 包名错误

一、命令如下
adb shell dumpsys window windows | grep -E "mCurrentFocus | mFocusedApp" | egrep "ActivityRecord.*" | cut -d " " -f7 | cut -d "/" -f1

通过adb shell dumpsys window windows命令可以得知以上命令获取的是什么内容：

  mCurConfiguration={1.0 ?mcc?mnc en_US ?layoutDir sw320dp w320dp h544dp 240dpi nrml long port finger -keyb/v/h -nav/h s.5}

  mHasPermanentDpad=false

  mCurrentFocus=Window{343a0a2c u0 com.tct.launcher/com.tct.launcher.Launcher}
  mFocusedApp=AppWindowToken{158efe19 token=Token{1f33d960 ActivityRecord{3ad78963 u0 com.tct.launcher/.Launcher t56}}}

二、步骤

root@aclgcl-ubnt:~# 桌面执行命令
root@aclgcl-ubnt:~# adb shell dumpsys window windows | grep -E "mCurrentFocus | mFocusedApp" | egrep "ActivityRecord.*" | cut -d " " -f7 | cut -d "/" -f1
com.tct.launcher
root@aclgcl-ubnt:~#
root@aclgcl-ubnt:~# 下面点击mms后执行命令
root@aclgcl-ubnt:~# adb shell dumpsys window windows | grep -E "mCurrentFocus | mFocusedApp" | egrep "ActivityRecord.*" | cut -d " " -f7 | cut -d "/" -f1
com.android.mms
root@aclgcl-ubnt:~#
root@aclgcl-ubnt:~# 按Home键回到桌面执行命令
root@aclgcl-ubnt:~# adb shell dumpsys window windows | grep -E "mCurrentFocus | mFocusedApp" | egrep "ActivityRecord.*" | cut -d " " -f7 | cut -d "/" -f1
com.android.mms
 

返回桌面后执行命令得到的结果不正确。

三、分析

从adb shell dumpsys window windows结果来看，即为mFocusedApp获取错误，mFocusedApp的设置在WMS中：

@Override
public void setFocusedApp(IBinder token, boolean moveFocusNow) {
if (!checkCallingPermission(android.Manifest.permission.MANAGE_APP_TOKENS,
"setFocusedApp()")) {
throw new SecurityException("Requires MANAGE_APP_TOKENS permission");
}

synchronized(mWindowMap) {
final AppWindowToken newFocus;
if (token == null) {
if (DEBUG_FOCUS_LIGHT) Slog.v(TAG, "Clearing focused app, was " + mFocusedApp);
newFocus = null;
} else {
newFocus = findAppWindowToken(token);
if (newFocus == null) {
Slog.w(TAG, "Attempted to set focus to non-existing app token: " + token);
}
if (DEBUG_FOCUS_LIGHT) Slog.v(TAG, "Set focused app to: " + newFocus
+ " old focus=" + mFocusedApp + " moveFocusNow=" + moveFocusNow);
}

final boolean changed = mFocusedApp != newFocus;
if (changed) {
mFocusedApp = newFocus;
mInputMonitor.setFocusedAppLw(newFocus);
}

if (moveFocusNow && changed) {
final long origId = Binder.clearCallingIdentity();
updateFocusedWindowLocked(UPDATE_FOCUS_NORMAL, true /*updateInputWindows*/);
Binder.restoreCallingIdentity(origId);
}
}
}

setFocusedApp在AMS中调用：

final void setFocusedActivityLocked(ActivityRecord r, String reason) {
if (mFocusedActivity != r) {
if (DEBUG_FOCUS) Slog.d(TAG, "setFocusedActivityLocked: r=" + r);
mFocusedActivity = r;
if (r.task != null && r.task.voiceInteractor != null) {
startRunningVoiceLocked();
} else {
finishRunningVoiceLocked();
}
mStackSupervisor.setFocusedStack(r, reason + " setFocusedActivity");
if (r != null) {
mWindowManager.setFocusedApp(r.appToken, true);
}
applyUpdateLockStateLocked(r);
}
EventLog.writeEvent(EventLogTags.AM_FOCUSED_ACTIVITY, mCurrentUserId,
mFocusedActivity == null ? "NULL" : mFocusedActivity.shortComponentName);
}

继续追踪setFocusedActivityLocked的几处调用，分别打log跟踪，发现当从mms按home键回到桌面的时候setFocusedActivityLocked方法没有被调用到，，，随后翻阅ActivityStack.java中的adjustFocusedActivityLocked方法所调用setFocusedActivityLocked的逻辑，

private void adjustFocusedActivityLocked(ActivityRecord r, String reason) {
if (mStackSupervisor.isFrontStack(this) && mService.mFocusedActivity == r) {
ActivityRecord next = topRunningActivityLocked(null);
if (next != r) {
final TaskRecord task = r.task;
if (r.frontOfTask && task == topTask() && task.isOverHomeStack()) {
mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo(),
reason + " adjustFocus");
}
}
ActivityRecord top = mStackSupervisor.topRunningActivityLocked();
if (top != null) {
mService.setFocusedActivityLocked(top, reason + " adjustTopFocus");
}
}
}

final void stopActivityLocked(ActivityRecord r) {
if (DEBUG_SWITCH) Slog.d(TAG, "Stopping: " + r);
if ((r.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_HISTORY) != 0
|| (r.info.flags&ActivityInfo.FLAG_NO_HISTORY) != 0) {
if (!r.finishing) {
if (!mService.isSleeping()) {
if (DEBUG_STATES) {
Slog.d(TAG, "no-history finish of " + r);
}
requestFinishActivityLocked(r.appToken, Activity.RESULT_CANCELED, null,
"no-history", false);
} else {
if (DEBUG_STATES) Slog.d(TAG, "Not finishing noHistory " + r
+ " on stop because we're just sleeping");
}
}
}

if (r.app != null && r.app.thread != null) {
adjustFocusedActivityLocked(r, "stopActivity");
r.resumeKeyDispatchingLocked();

在从mms回到launcher的时候，mms的activity被stop，所以应当是从adjustFocusedActivityLocked调用的setFocusedActivityLocked，所以是上面加红加粗的条件没有走进去，继续跟踪，查看isFrontStack()方法，

boolean isFrontStack(ActivityStack stack) {
final ActivityRecord parent = stack.mActivityContainer.mParentActivity;
if (parent != null) {
stack = parent.task.stack;
}
ArrayList<ActivityStack> stacks = stack.mStacks;
if (stacks != null && !stacks.isEmpty()) {
return stack == stacks.get(stacks.size() - 1);
}
return false;
}

通过log发现mStackSupervisor.isFrontStack(this)总是不成立，this是切换之前的stack，即MMS所在的stack，继续查看Android M中的代码，发现moveTaskToFrontLocked方法中也调用了mService.setFocusedActivityLocked(r, reason);，

final void moveTaskToFrontLocked(TaskRecord tr, boolean noAnimation, Bundle options,
AppTimeTracker timeTracker, String reason) {
System.out.println("ran.zhou-AS-L3721-moveTaskToFrontLocked");
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH, "moveTaskToFront: " + tr);

final int numTasks = mTaskHistory.size();
final int index = mTaskHistory.indexOf(tr);
。。。
。。。
// Shift all activities with this task up to the top
// of the stack, keeping them in the same internal order.
insertTaskAtTop(tr, null);

// Set focus to the top running activity of this stack.
ActivityRecord r = topRunningActivityLocked(null);
mService.setFocusedActivityLocked(r, reason);

if (DEBUG_TRANSITION) Slog.v(TAG_TRANSITION, "Prepare to front transition: task=" + tr);
if (noAnimation) {
mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
if (r != null) {
mNoAnimActivities.add(r);
}
ActivityOptions.abort(options);
} else {
updateTransitLocked(AppTransition.TRANSIT_TASK_TO_FRONT, options);
}

此处调用setFocusedActivityLocked方法走的不是stopActivity那条路了，而是ActivityStackSupervisor.java中的startActivityUncheckedLocked方法中，

final int startActivityUncheckedLocked(final ActivityRecord r, ActivityRecord sourceRecord,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor, int startFlags,
boolean doResume, Bundle options, TaskRecord inTask) {
final Intent intent = r.intent;
final int callingUid = r.launchedFromUid;
。。。。。。。
。。。。。。。
targetStack.moveTaskToFrontLocked(intentActivity.task, noAnimation,
options, r.appTimeTracker, "bringingFoundTaskToFront");

所以M中的处理是在moveTaskToFrontLocked加一个调用setFocusedActivityLocked。

Android M中对stopActivity的逻辑也是和Android L中一样，那个if条件走不进去，个人认为这里依然是Google的代码缺陷。

四、解决方案

仿照M中的处理，在moveTaskToFrontLocked加一个调用setFocusedActivityLocked。

//Added by xxx for PR-1150738 Begin
// Set focus to the top running activity of this stack.
ActivityRecord r = topRunningActivityLocked(null);
mService.setFocusedActivityLocked(r, reason);
//Added by xxx for PR-1150738 End