Android6.0 WMS（一） WMS和应用进程的关系
之前在分析Activity的时候有很多和WMS相关的，我们这里再简单总结下和WMS相关的那部分。
一、appToken在WMS中创建
在博客http://blog.csdn.net/kc58236582/article/details/52413871中在APPWindowToken创建过程这节中，我们分析到在AMS调用startActivityLocked的时候，会调用WMS的addAppToken来创建一个APPWindowToken。
final void startActivityLocked(ActivityRecord r, boolean newTask,
boolean doResume, boolean keepCurTransition, Bundle options) {
TaskRecord rTask = r.task;
final int taskId = rTask.taskId;
// mLaunchTaskBehind tasks get placed at the back of the task stack.
if (!r.mLaunchTaskBehind && (taskForIdLocked(taskId) == null || newTask)) {
// Last activity in task had been removed or ActivityManagerService is reusing task.
// Insert or replace.
// Might not even be in.
insertTaskAtTop(rTask, r);
mWindowManager.moveTaskToTop(taskId);
}
TaskRecord task = null;
if (!newTask) {
// If starting in an existing task, find where that is...
boolean startIt = true;
for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
task = mTaskHistory.get(taskNdx);
if (task.getTopActivity() == null) {
// All activities in task are finishing.
continue;
}
if (task == r.task) {
// Here it is! Now, if this is not yet visible to the
// user, then just add it without starting; it will
// get started when the user navigates back to it.
if (!startIt) {
if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to task "
+ task, new RuntimeException("here").fillInStackTrace());
task.addActivityToTop(r);
r.putInHistory();
mWindowManager.addAppToken(task.mActivities.indexOf(r), r.appToken,
r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
(r.info.flags & ActivityInfo.FLAG_SHOW_FOR_ALL_USERS) != 0,
r.userId, r.info.configChanges, task.voiceSession != null,
r.mLaunchTaskBehind);我们再来看看WMS的addAppToken函数，在WMS中创建了APPWindowToken然后保存在mTokenMap中。
public void addAppToken(int addPos, IApplicationToken token, int taskId, int stackId,
int requestedOrientation, boolean fullscreen, boolean showForAllUsers, int userId,
int configChanges, boolean voiceInteraction, boolean launchTaskBehind) {
......
synchronized(mWindowMap) {
AppWindowToken atoken = findAppWindowToken(token.asBinder());//如果已经有了直接退出
if (atoken != null) {
Slog.w(TAG, "Attempted to add existing app token: " + token);
return;
}
atoken = new AppWindowToken(this, token, voiceInteraction);//新建一个APPWindowToken
atoken.inputDispatchingTimeoutNanos = inputDispatchingTimeoutNanos;
atoken.appFullscreen = fullscreen;
atoken.showForAllUsers = showForAllUsers;
atoken.requestedOrientation = requestedOrientation;
atoken.layoutConfigChanges = (configChanges &
(ActivityInfo.CONFIG_SCREEN_SIZE | ActivityInfo.CONFIG_ORIENTATION)) != 0;
atoken.mLaunchTaskBehind = launchTaskBehind;
if (DEBUG_TOKEN_MOVEMENT || DEBUG_ADD_REMOVE) Slog.v(TAG, "addAppToken: " + atoken
+ " to stack=" + stackId + " task=" + taskId + " at " + addPos);
Task task = mTaskIdToTask.get(taskId);
if (task == null) {
task = createTaskLocked(taskId, stackId, userId, atoken);
}
task.addAppToken(addPos, atoken);
mTokenMap.put(token.asBinder(), atoken);//保存在mTokenMap中 token为key（Activity的binder对象）
// Application tokens start out hidden.
atoken.hidden = true;
atoken.hiddenRequested = true;
}
}
再来看看AppWindowToken的构造函数，它是WindowToken的子类，再调用父类构造函数的时候说明了自己是TYPE_APPLICATION类型的。参数_token指向的是一个ActivityRecord对象的IBinder接口，因此，AppWindowToken类的成员变量appToken描述的就是一个ActivityRecord对象。
AppWindowToken(WindowManagerService _service, IApplicationToken _token,
boolean _voiceInteraction) {
super(_service, _token.asBinder(),
WindowManager.LayoutParams.TYPE_APPLICATION, true);
appWindowToken = this;
appToken = _token;
voiceInteraction = _voiceInteraction;
mInputApplicationHandle = new InputApplicationHandle(this);
mAnimator = service.mAnimator;
mAppAnimator = new AppWindowAnimator(this);
}
二、Activity的attach函数
首先在博客http://blog.csdn.net/kc58236582/article/details/52397657中主要分析了Activity的创建 初始化。
handleLaunchActivity函数先调用performLaunchActivity函数，再调用handleResumeActivity函数。
在performLaunchActivity函数先新建Activity，然后调用其attach函数，最后调用了Activity的onCreate函数。
在Activity的attach函数中，主要代码如下：
......
mWindow = new PhoneWindow(this);//新建PhoneWindow对象
mWindow.setCallback(this);//这window中设置回调，在按键事件分发的时候中用到。如果有这个回调，就调用Activity的dispatchKeyEvent
mWindow.setOnWindowDismissedCallback(this);
......
mWindow.setWindowManager(
(WindowManager)context.getSystemService(Context.WINDOW_SERVICE),
mToken, mComponent.flattenToString(),
(info.flags & ActivityInfo.FLAG_HARDWARE_ACCELERATED) != 0);
if (mParent != null) {
mWindow.setContainer(mParent.getWindow());
}
mWindowManager = mWindow.getWindowManager();
三、创建ViewRootImpl、DecorView
我们继续分析，在http://blog.csdn.net/kc58236582/article/details/52411791博客，我们分析到了ViewRootImpl和DecorView的创建。
一般在Activity的onCreate函数中会调用setContentView。而在setContentView会创建DecorView对象。
下面我们再从ActivityThread的handleResumeActivity函数看，先调用了performResumeActivity函数来查找这个Activity，后面主要调用了WindowManager的addView函数。
final void handleResumeActivity(IBinder token,
boolean clearHide, boolean isForward, boolean reallyResume) {
// If we are getting ready to gc after going to the background, well
// we are back active so skip it.
unscheduleGcIdler();
mSomeActivitiesChanged = true;
// TODO Push resumeArgs into the activity for consideration
ActivityClientRecord r = performResumeActivity(token, clearHide);
if (r != null) {
final Activity a = r.activity;
if (localLOGV) Slog.v(
TAG, "Resume " + r + " started activity: " +
a.mStartedActivity + ", hideForNow: " + r.hideForNow
+ ", finished: " + a.mFinished);
final int forwardBit = isForward ?
WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION : 0;
// If the window hasn't yet been added to the window manager,
// and this guy didn't finish itself or start another activity,
// then go ahead and add the window.
boolean willBeVisible = !a.mStartedActivity;
if (!willBeVisible) {
try {
willBeVisible = ActivityManagerNative.getDefault().willActivityBeVisible(
a.getActivityToken());
} catch (RemoteException e) {
}
}
if (r.window == null && !a.mFinished && willBeVisible) {
r.window = r.activity.getWindow();
View decor = r.window.getDecorView();
decor.setVisibility(View.INVISIBLE);
ViewManager wm = a.getWindowManager();
WindowManager.LayoutParams l = r.window.getAttributes();
a.mDecor = decor;
l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
l.softInputMode |= forwardBit;
if (a.mVisibleFromClient) {
a.mWindowAdded = true;
wm.addView(decor, l);
}
我们来看WindowManagerImpl的addView函数，其实就是调用了WindowManagerGlobal的addView函数
@Override
public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
applyDefaultToken(params);
mGlobal.addView(view, params, mDisplay, mParentWindow);
}
之前也分析过WindowManagerGlobal，它有3个重要的成员变量：
private final ArrayList<View> mViews = new ArrayList<View>();//所有的DecorView对象
private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>();//所有的ViewRootImpl对象
private final ArrayList<WindowManager.LayoutParams> mParams =//所有顶层View的layout参数
new ArrayList<WindowManager.LayoutParams>();
们再来看WindowManagerGlobal的addView函数，这个函数先是查找是否已经在WindowManagerGlobal中已经有这个view，如果有的话就调用其ViewRootImpl的doDie函数中主要是调用WindowManagerGlobal函数去除这个ViewRootImpl对象，在这个主要是创建了ViewRootImpl，并且把DecorView，RootViewRootImpl，layout参数都保存起来了。然后调用了ViewRootImpl的setView函数。
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow) {
......
int index = findViewLocked(view, false);//查找是否有该view，获取其index
if (index >= 0) {
if (mDyingViews.contains(view)) {
// Don't wait for MSG_DIE to make it's way through root's queue.
mRoots.get(index).doDie();//调用ViewRootImpl的doDie函数
} else {
throw new IllegalStateException("View " + view
+ " has already been added to the window manager.");
}
// The previous removeView() had not completed executing. Now it has.
}
......
root = new ViewRootImpl(view.getContext(), display);//新建ViewRootImpl对象
view.setLayoutParams(wparams);
mViews.add(view);//成员变量增加
mRoots.add(root);
mParams.add(wparams);
}
// do this last because it fires off messages to start doing things
try {
root.setView(view, wparams, panelParentView);//调用ViewRootImpl的setView函数
} catch (RuntimeException e) {
// BadTokenException or InvalidDisplayException, clean up.
synchronized (mLock) {
final int index = findViewLocked(view, false);
if (index >= 0) {
removeViewLocked(index, true);
}
}
throw e;
}
}
四、ViewRootImpl的setView函数
上面在创建完ViewRootImpl之后会调用其setView函数，setView函数主要可以分成两个部分。
4.1 requestLayout函数
在setView中先会调用requestLayout函数，这个函数在http://blog.csdn.net/kc58236582/article/details/52421683博客中有详细分析，主要调用了WMS的relayoutWindow函数，然后通过SurfaceFlinger来创建一个Surface
4.2 addToDisplay
另一部分就是如下代码，最终会调用WMS的addWindow函数，增加窗口。在http://blog.csdn.net/kc58236582/article/details/52413871博客中WindowState的创建过程那节中有详细分析。
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
getHostVisibility(), mDisplay.getDisplayId(),
mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
mAttachInfo.mOutsets, mInputChannel);