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这篇文章主要介绍“Android10原理机制系列之Activity窗口添加到WMS过程是什么”,在日常操作中,相信很多人在Android10原理机制系列之Activity窗口添加到WMS过程是什么问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”Android10原理机制系列之Activity窗口添加到WMS过程是什么”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!
前言
首先看一个Android界面的布局层次结构,最直观的看一下:
我们能清晰看到,这个界面分成了3部分:顶部状态栏(statusbar)、底部导航栏(navigationbar)、应用界面。
题外话:
查看布局的层次结构,工具或途径可以参考下面的。
Android Studio:Tools->Layout Inspector->选择要查看的进程;
SDK Tools:tools/hierarchyviewer.bat。 不过最新推荐用tools/monitor.bat代替单独的hierarchyviewer.bat;hierarchyviewer.bat在工程目录下也存在prebuilts/devtools/tools
第二部分 综述总结 ,先将上述两个过程的内容做了比较简洁的总结。
第三部分 Activity窗口添加过程 ,跟踪源码详细 讲述了 Activity窗口的创建过程 以及 添加到WMS过程。
由于第三部分 跟踪源码,这个过程比较长,涉及比较多,相对枯燥。所以把总结先放到了第二部分。这样,如果了解过源码或这个过程的,可以只看第二部分。没了解过的,也可以通过第二部分有个大概了解,再查看第三部分,若遇到不太清楚的部分,可以再回到第二部分,对比理解。
该篇也是基于Android10的源码。
若有不对或不足,欢迎指点。
综述总结
前言已经介绍了为什么将总结放在了前面。下面具体看下。
第二部分,主要介绍了下面几个内容:
Window类型:窗口类型介绍
几个重要类:窗口创建添加到WMS过程中常见的一些类,了解下他们之间的关系
Activity创建窗口添加到WMS综述:简单总结了下 Activity的创建过程 和 添加到WMS过程
Activity中的一些结构示意图:整个过程,Activity中关联的一些类/结构的 关系,理解这个个人觉得很有必要
Token传递到WMS:Token是很重要的参数,参与整个过程。这里将该篇涉及的过程中的 Token的传递过程单独总结了下
Window类型
//WindowManager.java public static class LayoutParams extends ViewGroup.LayoutParams implements Parcelable { public static final int FIRST_APPLICATION_WINDOW = 1; public static final int LAST_APPLICATION_WINDOW = 99; public static final int FIRST_SUB_WINDOW = 1000; public static final int LAST_SUB_WINDOW = 1999; public static final int FIRST_SYSTEM_WINDOW = 2000; public static final int LAST_SYSTEM_WINDOW = 2999; //状态栏 public static final int TYPE_STATUS_BAR = FIRST_SYSTEM_WINDOW; //搜索栏 public static final int TYPE_SEARCH_BAR = FIRST_SYSTEM_WINDOW+1; //来电显示 public static final int TYPE_PHONE = FIRST_SYSTEM_WINDOW+2; //警告窗口,常见如:低电量警告 public static final int TYPE_SYSTEM_ALERT = FIRST_SYSTEM_WINDOW+3; //锁屏 public static final int TYPE_KEYGUARD = FIRST_SYSTEM_WINDOW+4; //toast public static final int TYPE_TOAST = FIRST_SYSTEM_WINDOW+5; public static final int TYPE_SYSTEM_OVERLAY = FIRST_SYSTEM_WINDOW+6;//显示在所有窗口之上,覆盖 //来电优先,即使锁屏状态下 public static final int TYPE_PRIORITY_PHONE = FIRST_SYSTEM_WINDOW+7; //输入法窗口 public static final int TYPE_INPUT_METHOD = FIRST_SYSTEM_WINDOW+11; //壁纸 public static final int TYPE_WALLPAPER = FIRST_SYSTEM_WINDOW+13; }
应用窗口(1 ~ 99):FIRST_APPLICATION_WINDOW ~ LAST_APPLICATION_WINDOW。对应一个Activity,token需设置成Activity的token。 如:Activity。
子窗口(1000 ~ 1999):FIRST_SUB_WINDOW ~ LAST_SUB_WINDOW。必须要有一个父窗口,token需设置成父窗口的token。 如:PopupWindow,依附于Activity。
系统窗口(2000 ~ 2999):FIRST_SYSTEM_WINDOW ~ LAST_SYSTEM_WINDOW。系统级的 不需要对应Activity 也不需要有父窗口,应用进程一般没有权限创建,只有系统进程可以创建。如:上面列出了部分常见的系统窗口,状态栏、来电、toast、输入法等等。
几个重要类
下面几个类是后续经常看到的,这里主要看下他们直接的继承关系,后面看到比较容易理解。
public abstract class Window {} public class PhoneWindow extends Window implements MenuBuilder.Callback {} public interface WindowManagerPolicy extends WindowManagerPolicyConstants {} public class PhoneWindowManager implements WindowManagerPolicy {} public interface ViewManager { public void addView(View view, ViewGroup.LayoutParams params); public void updateViewLayout(View view, ViewGroup.LayoutParams params); public void removeView(View view); } public interface WindowManager extends ViewManager {} public final class WindowManagerImpl implements WindowManager {} /** A window in the window manager. */ class WindowState extends WindowContainer<WindowState> implements WindowManagerPolicy.WindowState {}
Window是一个抽象类,Activity、Toast、Dialog等都是靠Window来呈现。
PhoneWindow是Window的具体实现类(几乎是唯一实现类)。
WindowManager是个接口,继承接口 ViewManager(ViewManager定义了3个操作:增加、更新、移除)。
WindowManagerImpl是WindowManager的实现类。
不过查看WindowManagerImpl中 关于ViewManager的3个操作可以看出,这3个实现 最终是交由WindowManagerGlobal完成的。
WindowState维护着窗口的所有信息。WMS通过WindowState对窗口进行管理、保存状态等。
Activity创建窗口添加到WMS综述
这是跟踪的代码过程,这里汇总下 方便后续查看理解。 红色是比较主要的几个节点方法。
//attach() -performLaunchActivity() --activity.attach()//创建了PhoneWindow(mWindow)。mWindowManager保存的是 从mWindow处获取的 setWindowManager()创建的WindowManagerImpl ---mWindow.setWindowManager()//PhoneWindow内部 创建了WindowManagerImpl(mWindowManager),并保存了appToken、appName。 //onCreate() -setContentView() --installDecor() ---generateDecor()//创建了DecorView(mDecor) ---generateLayout()//将activity的布局作为子视图(ViewGroup)添加到mDecor中 //onResume() -r.activity.makeVisible()// --wm.addView(mDecor, ...)//wm即mWindowManager(WindowManagerImpl对象) ---WindowManagerGlobal.addView()//创建了ViewRootImpl。addView的view是mDecor,ViewRootImpl中创建了mWindow(这里是一个IBinder,而非attach()中创建的) ----ViewRootImpl.setView()//openSession()创建了Session(IWindowSession的代理类),view也是mDecor。mDecor传入到ViewRootImpl的mView -----Session.addToDisplay()//通过Session进入system_server进程 ------mService.addWindow()//进入WMS,执行addWindow()添加窗口
attach阶段:
一个Activity 创建了一个PhoneWindow对象 ,PhoneWindow通过setWindowManager() 创建了WindowManagerImpl 。
即Activity 对应一个PhoneWindow,并得到了一个WindowManager(WindowManagerImpl,Window创建的)。
onCreate阶段:
创建了DecorView,并将 activity的布局添加到DecorView中 。
onResume阶段:
创建了ViewRootImpl,通过setView()最终由Session进入system_server进程。最终执行addWindow添加窗口到WMS。
Activity中的一些结构示意图
下面是我学习总结中 根据理解画的,方便自己查看时一眼可得。
(若有什么不对,多谢指点)
public final class WindowManagerImpl implements WindowManager { private final WindowManagerGlobal mGlobal = WindowManagerGlobal.getInstance(); } public final class WindowManagerGlobal { private static IWindowManager sWindowManagerService;//WMS客户端, private static IWindowSession sWindowSession;//Session private final ArrayList<View> mViews = new ArrayList<View>(); private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>(); private final ArrayList<WindowManager.LayoutParams> mParams = new ArrayList<WindowManager.LayoutParams>(); }
一个Activity对应了一个PhoneWindow对象。即 每个Activity对应一个Window (具体实现类是PhoneWindow)。
一个PhoneWindow 持有一个 DecorView 实例, DecorView实际是一个FrameLayout,它是Activity中所有View的根(最顶层的View)。
一个PhoneWindow有一个WindowManagerImpl。WindowManagerImpl持有一个单例WindowManagerGlobal。
Token传递到WMS
Activity启动时 AMS会为其创建一个ActivityRecord。可以参考: AMS之应用的第一次启动过程 。
下面先看下ActivityRecord中关于token的几处代码:
final class ActivityRecord extends ConfigurationContainer { final IApplicationToken.Stub appToken; // window manager token // TODO: Remove after unification AppWindowToken mAppWindowToken; ActivityRecord(ActivityTaskManagerService _service, WindowProcessController _caller,...) { appToken = new Token(this, _intent); } void createAppWindowToken() { mAppWindowToken = createAppWindow(mAtmService.mWindowManager, appToken,...); } static class Token extends IApplicationToken.Stub { Token(ActivityRecord activity, Intent intent) { weakActivity = new WeakReference<>(activity); name = intent.getComponent().flattenToShortString(); } } }
ActivityRecord中的成员变量 appToken ,这个很重要,后续很多地方会一直涉及到。
ActivityRecord中有个 appToken ,其是一个IBinder(内部类Token继承了IApplicationToken接口)。Token内部持有Activity的弱引用。
在ActivityRecord中会通过createAppWindow()创建并保存 AppWindowToken对象 到mAppWindowToken。
mAppWindowToken:这个appToken会被封装在其中。路径:ActivityStack.startActivityLocked()->ActivityRecord.createAppWindowToken()。AppWindowToken是WindowToken子类。WindowToken可以标志一个窗口。
这个appToken,会在Activity.attach()中作为参数传递到Activity。
Activity保存到mToken。
然后通过 Activity.attach()->mWindow.setWindowManager() 传入到Window(PhoneWindow)中。
Window保存到mAppToken。
WindowManagerGlobal.addView()->Window.adjustLayoutParamsForSubWindow()保存到WindowManager.LayoutParams中的token变量中。
最后WindowManager.LayoutParams(其中token即ActivityRecord中的appToken)作为参数传入ViewRootImpl.setView()。
ViewRootImpl中mWindowAttributes拷贝了WindowManager.LayoutParams,作为参数通过Session.addToDisplay()传入WMS中,进行后续操作。
这是整个添加窗口(到addWindow())过程 appToken参与的过程及传递过程。
appToken如何参与窗口的添加,这个在 “第三部分的2.8:mService.addWindow()” 注释中能大致看到,比较详细。
Activity窗口添加过程
这里主要介绍 Activity对应Window的创建 以及 Window添加到WMS的过程。
Activity窗口创建
在 AMS之应用的第一次启动过程 中,从点击应用图标到activity创建并执行onCreate()。 下面部分是后面部分的截取,不清楚可以参考下那篇文章。
1.1:handleLaunchActivity()
这里从handleLaunchActivity()开始。
//ActivityThread.java @Override public Activity handleLaunchActivity(ActivityClientRecord r, PendingTransactionActions pendingActions, Intent customIntent) { ... WindowManagerGlobal.initialize(); final Activity a = performLaunchActivity(r, customIntent); ... } private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) { ... try { java.lang.ClassLoader cl = appContext.getClassLoader(); activity = mInstrumentation.newActivity( cl, component.getClassName(), r.intent); } try { Application app = r.packageInfo.makeApplication(false, mInstrumentation); if (activity != null) { Window window = null; ... //attach(),注意这个r.token。参考1.2 activity.attach(appContext, this, getInstrumentation(), r.token, r.ident, app, r.intent, r.activityInfo, title, r.parent, r.embeddedID, r.lastNonConfigurationInstances, config, r.referrer, r.voiceInteractor, window, r.configCallback, r.assistToken); if (r.isPersistable()) { //callActivityOnCreate() 最终执行到的activity的onCreate()方法。 //参考1.4 mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState); } else { mInstrumentation.callActivityOnCreate(activity, r.state); } } } ... return activity; }
WindowManagerGlobal.initialize(); 是获取WMS的IBinder代理类,用于与WMS通信。这里不列出代码了。
接着要看的是 activity.attach() 。注意作为参数传入attach()的 r.token 是个IBinder,来自ActivityClientRecord,简单看标识了一个Activity。
1.2:activity.attach()
//Activity.java final void attach(Context context, ActivityThread aThread, Instrumentation instr, IBinder token, ...) { ... //创建PhoneWindow mWindow = new PhoneWindow(this, window, activityConfigCallback);//创建PhoneWindow //设置软键盘 if (info.softInputMode != WindowManager.LayoutParams.SOFT_INPUT_STATE_UNSPECIFIED) { mWindow.setSoftInputMode(info.softInputMode); } //token保存到mToken。 mToken = token; ... //mToken传入到Window,参考1.3 mWindow.setWindowManager( (WindowManager)context.getSystemService(Context.WINDOW_SERVICE), mToken, mComponent.flattenToString(), (info.flags & ActivityInfo.FLAG_HARDWARE_ACCELERATED) != 0); //mWindowManager即setWindowManager()中创建的WindowManagerImpl。 mWindowManager = mWindow.getWindowManager(); ... }
首先创建了Activityd对应的Window,是PhoneWindow-Window的实现类。 接着看 mWindow.setWindowManager() 。
1.3:mWindow.setWindowManager()
//Window.java public void setWindowManager(WindowManager wm, IBinder appToken, String appName, boolean hardwareAccelerated) { //ActivityClientRecord.token mAppToken = appToken; mAppName = appName; mHardwareAccelerated = hardwareAccelerated; if (wm == null) { wm = (WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE); } //创建了WindowManagerImpl,注意WindowManagerImpl中mParentWindow是this,非空 mWindowManager = ((WindowManagerImpl)wm).createLocalWindowManager(this); }
这里创建了WindowManagerImpl对象,即WindowManager的实现类。并保存了appToken、appName、mWindowManager。
通过setWindowManager(),即为Window(或者PhoneWindow)设置创建了WindowManager(WindowManagerImpl)。
1.4:setContentView()
mInstrumentation.callActivityOnCreate() 最终有调用到Activity的onCreate()。
自定义Activity,设置布局都执行了 setContentView() ,下面直接来看下这个方法。
//Activity.java public void setContentView(@LayoutRes int layoutResID) { getWindow().setContentView(layoutResID);// initWindowDecorActionBar(); } public Window getWindow() { return mWindow;//即PhoneWindow对象 } //PhoneWindow.java // This is the top-level view of the window, containing the window decor. private DecorView mDecor; @Override public void setContentView(int layoutResID) { // Note: FEATURE_CONTENT_TRANSITIONS may be set in the process of installing the window // decor, when theme attributes and the like are crystalized. Do not check the feature // before this happens. if (mContentParent == null) { installDecor();// } else if (!hasFeature(FEATURE_CONTENT_TRANSITIONS)) { mContentParent.removeAllViews(); } if (hasFeature(FEATURE_CONTENT_TRANSITIONS)) { final Scene newScene = Scene.getSceneForLayout(mContentParent, layoutResID, getContext()); transitionTo(newScene); } else { mLayoutInflater.inflate(layoutResID, mContentParent); } ... } private void installDecor() { mForceDecorInstall = false; if (mDecor == null) { //生成DecorView,参考1.5 mDecor = generateDecor(-1); ... } else { mDecor.setWindow(this); } if (mContentParent == null) { //布局添加到DecorView,参考1.5 mContentParent = generateLayout(mDecor); // Set up decor part of UI to ignore fitsSystemWindows if appropriate. mDecor.makeOptionalFitsSystemWindows(); final DecorContentParent decorContentParent = (DecorContentParent) mDecor.findViewById( R.id.decor_content_parent); if (decorContentParent != null) { } else { mTitleView = findViewById(R.id.title); } ... } }
这里主要关注下两个方法: mDecor = generateDecor(-1); 和 mContentParent = generateLayout(mDecor); 。
先看下他们的相关代码:
1.5:generateDecor()和generateLayout()
protected DecorView generateDecor(int featureId) { // System process doesn't have application context and in that case we need to directly use // the context we have. Otherwise we want the application context, so we don't cling to the // activity. Context context; ... return new DecorView(context, featureId, this, getAttributes());// } public class DecorView extends FrameLayout implements RootViewSurfaceTaker, WindowCallbacks { } protected ViewGroup generateLayout(DecorView decor) { ... mDecor.startChanging(); mDecor.onResourcesLoaded(mLayoutInflater, layoutResource); ViewGroup contentParent = (ViewGroup)findViewById(ID_ANDROID_CONTENT); ... mDecor.finishChanging(); return contentParent; } //DecorView.java void onResourcesLoaded(LayoutInflater inflater, int layoutResource) { ... mDecorCaptionView = createDecorCaptionView(inflater); final View root = inflater.inflate(layoutResource, null); if (mDecorCaptionView != null) { if (mDecorCaptionView.getParent() == null) { addView(mDecorCaptionView, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT)); } mDecorCaptionView.addView(root, new ViewGroup.MarginLayoutParams(MATCH_PARENT, MATCH_PARENT)); } else { // Put it below the color views. addView(root, 0, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT)); } mContentRoot = (ViewGroup) root; initializeElevation(); }
通过 generateDecor() 创建了一个DecorView。DecorView实际是一个FrameLayout。
然后通过 generateLayout() ,最终将activity的布局作为子视图(ViewGroup)添加到DecorView中。
上面可以看到,activity生成到执行onCreate(),这个过程,activity生成了关联的PhoneWindow,然后创建了WindowManagerImpl、DecorView。
下面看下Window添加到WMS的过程,看这些创建的对象之前如何联系 形成的一开始介绍的结构示意图。
Window添加到WMS过程
在 AMS之应用的第一次启动过程 中主要讲到onCreate,其实onResume也在其中在,这里不详细解释了,再次列出相关代码:
//ActivityStackSupervisor.java: boolean realStartActivityLocked(ActivityRecord r, WindowProcessController proc, boolean andResume, boolean checkConfig) throws RemoteException { ... try { ... try { // Create activity launch transaction. final ClientTransaction clientTransaction = ClientTransaction.obtain( proc.getThread(), r.appToken); final DisplayContent dc = r.getDisplay().mDisplayContent; clientTransaction.addCallback(LaunchActivityItem.obtain(new Intent(r.intent), ... // Set desired final state. final ActivityLifecycleItem lifecycleItem; if (andResume) { lifecycleItem = ResumeActivityItem.obtain(dc.isNextTransitionForward()); } else { lifecycleItem = PauseActivityItem.obtain(); } clientTransaction.setLifecycleStateRequest(lifecycleItem); // Schedule transaction. mService.getLifecycleManager().scheduleTransaction(clientTransaction); ... } } ... return true; }
通过 LaunchActivityItem 关联 最终执行结果是创建了应用的Activity 并 执行了attach()和onCreate()。 andResume为true(传入的参数为true,可以参考那篇这段代码往前看), 通过 ResumeActivityItem 关联 最终执行到的是 ActivityThread.handleResumeActivity()。
这里从ActivityThread.handleResumeActivity()来看。
2.1:ActivityThread.handleResumeActivity()
//ActivityThread.java @Override public void handleResumeActivity(IBinder token, boolean finalStateRequest, boolean isForward, String reason) { ... // TODO Push resumeArgs into the activity for consideration //执行onStart()->onResume()。参考2.2 final ActivityClientRecord r = performResumeActivity(token, finalStateRequest, reason); final Activity a = r.activity; 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; ... } ... // The window is now visible if it has been added, we are not // simply finishing, and we are not starting another activity. if (!r.activity.mFinished && willBeVisible && r.activity.mDecor != null && !r.hideForNow) { ... r.activity.mVisibleFromServer = true; mNumVisibleActivities++; if (r.activity.mVisibleFromClient) { //参考2.3 r.activity.makeVisible(); } } ... }
注意 View decor = r.window.getDecorView(); 获取了DecorView对象,最后通过 a.mDecor = decor; 将DecorView赋到了Activity中。
这里关注两个:
performResumeActivity() r.activity.makeVisible();
2.2:performResumeActivity()
//ActivityThread.java @VisibleForTesting public ActivityClientRecord performResumeActivity(IBinder token, boolean finalStateRequest, String reason) { final ActivityClientRecord r = mActivities.get(token); ... try { r.activity.onStateNotSaved(); r.activity.mFragments.noteStateNotSaved(); ... r.activity.performResume(r.startsNotResumed, reason); r.state = null; r.persistentState = null; r.setState(ON_RESUME); reportTopResumedActivityChanged(r, r.isTopResumedActivity, "topWhenResuming"); } return r; } //Activity.java final void performResume(boolean followedByPause, String reason) { performRestart(true /* start */, reason); mInstrumentation.callActivityOnResume(this); } final void performRestart(boolean start, String reason) { mInstrumentation.callActivityOnRestart(this); } //Instrumentation.java public void callActivityOnRestart(Activity activity) { activity.onRestart(); } public void callActivityOnResume(Activity activity) { activity.mResumed = true; activity.onResume(); ... }
performResumeActivity()中 r.activity.performResume() 回调Activity的performResume()方法。最终执行了Activity的onResume()方法。
performResume()在执行onResume前,调用了 performRestart() ,最终调用的是activity的onStart()。这里可以看出 onStart()执行在onResume()之前。
2.3:r.activity.makeVisible()
//Activity.java void makeVisible() { if (!mWindowAdded) { ViewManager wm = getWindowManager(); wm.addView(mDecor, getWindow().getAttributes()); mWindowAdded = true; } mDecor.setVisibility(View.VISIBLE); } //WindowManagerImpl.java public final class WindowManagerImpl implements WindowManager { @UnsupportedAppUsage private final WindowManagerGlobal mGlobal = WindowManagerGlobal.getInstance(); @Override public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) { applyDefaultToken(params); //mParentWindow即创建WindowManagerImpl是 传入的。参考2.4 mGlobal.addView(view, params, mContext.getDisplay(), mParentWindow); } }
这里的getWindowManager()获取到的是前面讲到的 attach()时通过setWindowManager()创建的WindowManagerImpl对象。
前面也讲过,addView()等3个操作定义实现 最终在WindowManagerGlobal中,这里就可以看到。
2.4:WindowManagerGlobal.addView()
//WindowManagerGlobal @UnsupportedAppUsage private final ArrayList<View> mViews = new ArrayList<View>(); @UnsupportedAppUsage private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>(); public void addView(View view, ViewGroup.LayoutParams params, Display display, Window parentWindow) { ... final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params; if (parentWindow != null) { //调整Window参数,这个过程将token设置其中了 //参考2.4.1 parentWindow.adjustLayoutParamsForSubWindow(wparams); } ... ViewRootImpl root; View panelParentView = null; synchronized (mLock) { ... root = new ViewRootImpl(view.getContext(), display); view.setLayoutParams(wparams); mViews.add(view); mRoots.add(root); mParams.add(wparams); try { //将view及相关参数设置到ViewRootImpl中。ViewRootImpl会向WMS添加新窗口、申请Surface及绘制工作等。 //参考2.6 root.setView(view, wparams, panelParentView); } ... } } //ViewRootImpl.java @UnsupportedAppUsage final IWindowSession mWindowSession; public ViewRootImpl(Context context, Display display) { mContext = context; //创建了Session(),参考2.5 mWindowSession = WindowManagerGlobal.getWindowSession(); mDisplay = display; mBasePackageName = context.getBasePackageName(); mThread = Thread.currentThread(); mTargetSdkVersion = context.getApplicationInfo().targetSdkVersion; //这里的mWindow不是前面Activity中的PhoneWindow,它是W extends IWindow.Stub mWindow = new W(this); mViewVisibility = View.GONE; //创建AttachInfo mAttachInfo = new View.AttachInfo(mWindowSession, mWindow, display, this, mHandler, this, context); ... } static class W extends IWindow.Stub {...} //ViewRootImpl.java public final class ViewRootImpl implements ViewParent, //View.java final static class AttachInfo { AttachInfo(IWindowSession session, IWindow window, Display display, ViewRootImpl viewRootImpl, Handler handler, Callbacks effectPlayer, Context context) { mSession = session; mWindow = window; mWindowToken = window.asBinder(); mDisplay = display; mViewRootImpl = viewRootImpl; mHandler = handler; mRootCallbacks = effectPlayer; mTreeObserver = new ViewTreeObserver(context); } }
这里主要看到,创建了ViewRootImpl对象。这个类实现了View与WindowManager之间必要的协议。
注意创建中的 mWindow = new W(this); ,这个W继承IWindow.Stub。
创建ViewRootImpl对象时 创建了一个 mAttachInfo = View.AttachInfo() , AttachInfo是一系列绑定信息。mWindowSession、mWindow作为参数传入。AttachInfo创建时注意 mWindowToken = window.asBinder(); 。
mWindowSession在后续2.5/2.6/2.7中讲到,它是Session对象,它是IWindowSession的代理类, 通过他可以与WMS通信的binder接口 。
mWindow这里是W对象,它是IWindow.Stub,通过new创建,后续能看到会传入WMS, 它是WMS回调应用(与应用通信)的binder接口 。
mWindowToken,也就是W的IBinder对象, 也是WMS与应用通信的接口 。
创建ViewRootImpl对象后,WindowManagerGlobal将View、ViewRootImpl、LayoutParams保存到相应的ArrayList中。前面也讲到过,WindowManagerGlobal是单例的,应用进程中只有一个。最后通过root.setView()将View(这里是DecorView)传入到ViewRootImpl中。
2.4.1:adjustLayoutParamsForSubWindow()
前面看到mAppToken是从Activity的传入的。
这里mAppToken被设置到WindowManager.LayoutParams里,后面可以看到最终传入到WMS参与处理。
//Window.java void adjustLayoutParamsForSubWindow(WindowManager.LayoutParams wp) { CharSequence curTitle = wp.getTitle(); //子窗口,该篇中是应用窗口,所以不走这,也了解下。 if (wp.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW && wp.type <= WindowManager.LayoutParams.LAST_SUB_WINDOW) { if (wp.token == null) { View decor = peekDecorView(); if (decor != null) { wp.token = decor.getWindowToken(); } } ... //系统窗口,也不走这 } else if (wp.type >= WindowManager.LayoutParams.FIRST_SYSTEM_WINDOW && wp.type <= WindowManager.LayoutParams.LAST_SYSTEM_WINDOW) { ... //应用窗口,该篇走这 } else { if (wp.token == null) { //设置到了WindowManager.LayoutParams中 wp.token = mContainer == null ? mAppToken : mContainer.mAppToken; } ... } ... }
2.4.2:AttachInfo在其中了解下
ViewRootImpl与各个View。通过下面的过程,AttachInfo绑定信息被设置到各个View中了,即各个View能够获取到各种相关信息。
2.6执行到ViewRootImpl.setView()后,参考过程:setView()->requestLayout()->scheduleTraversals()->mTraversalRunnable->doTraversal()->performTraversals()->host.dispatchAttachedToWindow(mAttachInfo, 0)->View.dispatchAttachedToWindow()->ViewGroup.dispatchAttachedToWindow()。
属同个ViewGroup的 AttachInfo是一样的。
//ViewGroup.java @Override @UnsupportedAppUsage void dispatchAttachedToWindow(AttachInfo info, int visibility) { mGroupFlags |= FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW; super.dispatchAttachedToWindow(info, visibility); mGroupFlags &= ~FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW; final int count = mChildrenCount; final View[] children = mChildren; for (int i = 0; i < count; i++) { final View child = children[i]; child.dispatchAttachedToWindow(info, combineVisibility(visibility, child.getVisibility())); } final int transientCount = mTransientIndices == null ? 0 : mTransientIndices.size(); for (int i = 0; i < transientCount; ++i) { View view = mTransientViews.get(i); view.dispatchAttachedToWindow(info, combineVisibility(visibility, view.getVisibility())); } } }
上述过程 performTraversals() 大致了解下:从上而下遍历视图树,每个View绘制自己,ViewGroup通知子View进行绘制。测量performMeasure() 执行布局performLayout() 绘制performDraw()。
Android绘制 重要的部分就在这里,需要了解的可以仔细研究下这个方法(performTraversals()),这里不作关注。
2.5:WindowManagerGlobal.getWindowSession()
// WindowManagerGlobal.java @UnsupportedAppUsage public static IWindowSession getWindowSession() { synchronized (WindowManagerGlobal.class) { if (sWindowSession == null) { try { InputMethodManager.ensureDefaultInstanceForDefaultDisplayIfNecessary(); IWindowManager windowManager = getWindowManagerService(); //创建Session对象 sWindowSession = windowManager.openSession( new IWindowSessionCallback.Stub() { @Override public void onAnimatorScaleChanged(float scale) { ValueAnimator.setDurationScale(scale); } }); } catch (RemoteException e) { throw e.rethrowFromSystemServer(); } } return sWindowSession; } } //WindowManagerService.java @Override public IWindowSession openSession(IWindowSessionCallback callback) { return new Session(this, callback); }
获取Sessiond对象,如果没有则通过 windowManager.openSession() 创建。Session是IWindowSession的代理类,然后返回给ViewRootImpl中的mWindowSession。
2.6:ViewRootImpl.setView()
//ViewRootImpl.java public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) { synchronized (this) { if (mView == null) { mView = view; mWindowAttributes.copyFrom(attrs); ... // Schedule the first layout -before- adding to the window // manager, to make sure we do the relayout before receiving // any other events from the system. requestLayout();//TODO try { mOrigWindowType = mWindowAttributes.type; mAttachInfo.mRecomputeGlobalAttributes = true; collectViewAttributes(); //参考2.7,进入system_server进程 res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes, getHostVisibility(), mDisplay.getDisplayId(), mTmpFrame, mAttachInfo.mContentInsets, mAttachInfo.mStableInsets, mAttachInfo.mOutsets, mAttachInfo.mDisplayCutout, mInputChannel, mTempInsets); setFrame(mTmpFrame); } ... } } }
res = mWindowSession.addToDisplay() :mWindowSession是上面返回的创建的Session, mWindowSession.addToDisplay() 即通过binder进入system_server进程,执行的Session.addToDisplay()。
mView即DecorView。
这里的mWindow是2.4中讲到的,是 W 继承IWindow.Stub。这是一个IBinder对象,在应用进程创建ViewRootImpl时被创建。
这里 mWindowSession.addToDisplay() 往后可以看到被传入到WMS。
2.7:Session.addToDisplay()
//Session.java class Session extends IWindowSession.Stub implements IBinder.DeathRecipient { final WindowManagerService mService; public Session(WindowManagerService service, IWindowSessionCallback callback) { mService = service; ... } @Override public int addToDisplay(IWindow window, int seq, WindowManager.LayoutParams attrs, int viewVisibility, int displayId, Rect outFrame, Rect outContentInsets, Rect outStableInsets, Rect outOutsets, DisplayCutout.ParcelableWrapper outDisplayCutout, InputChannel outInputChannel, InsetsState outInsetsState) { //参考2.8 return mService.addWindow(this, window, seq, attrs, viewVisibility, displayId, outFrame, outContentInsets, outStableInsets, outOutsets, outDisplayCutout, outInputChannel, outInsetsState); } }
进入WMS,添加Window。
2.8:mService.addWindow()
终于到最后WMS.addWindow(),这里完成窗口添加。可以仔细看下下面源码及注释,这个方法即使缩减了很多还是比较长,需要耐心。
//WindowManagerService.java public int addWindow(Session session, IWindow client, int seq, LayoutParams attrs, int viewVisibility, int displayId, Rect outFrame, Rect outContentInsets, Rect outStableInsets, Rect outOutsets, DisplayCutout.ParcelableWrapper outDisplayCutout, InputChannel outInputChannel, InsetsState outInsetsState) { int[] appOp = new int[1]; //检查权限,无权限不能添加窗口 int res = mPolicy.checkAddPermission(attrs, appOp); if (res != WindowManagerGlobal.ADD_OKAY) { return res; } boolean reportNewConfig = false; WindowState parentWindow = null; ... final int type = attrs.type; synchronized (mGlobalLock) { ... //获取窗口要添加到的DisplayContent。即显示在哪个屏幕上 final DisplayContent displayContent = getDisplayContentOrCreate(displayId, attrs.token); if (displayContent == null) { Slog.w(TAG_WM, "Attempted to add window to a display that does not exist: " + displayId + ". Aborting."); return WindowManagerGlobal.ADD_INVALID_DISPLAY; } if (!displayContent.hasAccess(session.mUid)) { Slog.w(TAG_WM, "Attempted to add window to a display for which the application " + "does not have access: " + displayId + ". Aborting."); return WindowManagerGlobal.ADD_INVALID_DISPLAY; } if (mWindowMap.containsKey(client.asBinder())) { Slog.w(TAG_WM, "Window " + client + " is already added"); return WindowManagerGlobal.ADD_DUPLICATE_ADD; } //添加子窗口,父窗口必须存在。 if (type >= FIRST_SUB_WINDOW && type <= LAST_SUB_WINDOW) { parentWindow = windowForClientLocked(null, attrs.token, false); if (parentWindow == null) { Slog.w(TAG_WM, "Attempted to add window with token that is not a window: " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN; } //这里可以看出WMS要求 窗口的层级 最多为两层 if (parentWindow.mAttrs.type >= FIRST_SUB_WINDOW && parentWindow.mAttrs.type <= LAST_SUB_WINDOW) { Slog.w(TAG_WM, "Attempted to add window with token that is a sub-window: " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN; } } if (type == TYPE_PRIVATE_PRESENTATION && !displayContent.isPrivate()) { Slog.w(TAG_WM, "Attempted to add private presentation window to a non-private display. Aborting."); return WindowManagerGlobal.ADD_PERMISSION_DENIED; } AppWindowToken atoken = null; final boolean hasParent = parentWindow != null; //获取WindowToken,对于子窗口使用父窗口的token。 //通过attrs.token从mTokenMap取出:private final HashMap<IBinder, WindowToken> mTokenMap = new HashMap(); //关于Activity窗口:WindowToken,前面讲过ActivityRecord 创建时会创建AppWindowToken,这个过程中appToken和AppWindowToken被保存到mTokenMap中 WindowToken token = displayContent.getWindowToken( hasParent ? parentWindow.mAttrs.token : attrs.token); // If this is a child window, we want to apply the same type checking rules as the // parent window type. final int rootType = hasParent ? parentWindow.mAttrs.type : type; boolean addToastWindowRequiresToken = false; //以下是WindowToken和窗口之间的关系 if (token == null) { //以下窗口类型,WindowToken不能为空 if (rootType >= FIRST_APPLICATION_WINDOW && rootType <= LAST_APPLICATION_WINDOW) { Slog.w(TAG_WM, "Attempted to add application window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (rootType == TYPE_INPUT_METHOD) { Slog.w(TAG_WM, "Attempted to add input method window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (rootType == TYPE_VOICE_INTERACTION) { Slog.w(TAG_WM, "Attempted to add voice interaction window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (rootType == TYPE_WALLPAPER) { Slog.w(TAG_WM, "Attempted to add wallpaper window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (rootType == TYPE_DREAM) { Slog.w(TAG_WM, "Attempted to add Dream window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (rootType == TYPE_QS_DIALOG) { Slog.w(TAG_WM, "Attempted to add QS dialog window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (rootType == TYPE_ACCESSIBILITY_OVERLAY) { Slog.w(TAG_WM, "Attempted to add Accessibility overlay window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (type == TYPE_TOAST) { // Apps targeting SDK above N MR1 cannot arbitrary add toast windows. if (doesAddToastWindowRequireToken(attrs.packageName, callingUid, parentWindow)) { Slog.w(TAG_WM, "Attempted to add a toast window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } } final IBinder binder = attrs.token != null ? attrs.token : client.asBinder(); final boolean isRoundedCornerOverlay = (attrs.privateFlags & PRIVATE_FLAG_IS_ROUNDED_CORNERS_OVERLAY) != 0; //token为空,除上述窗口类型,其他是允许的。此时新建WindowToken token = new WindowToken(this, binder, type, false, displayContent, session.mCanAddInternalSystemWindow, isRoundedCornerOverlay); //token不为空,且是应用窗口类型,token需要时AppWindowToken类型 } else if (rootType >= FIRST_APPLICATION_WINDOW && rootType <= LAST_APPLICATION_WINDOW) { //判断token是否是AppWindowToken类型 //前面知道,Activity创建的是AppWindowToken,即获得的atoken非空 atoken = token.asAppWindowToken(); if (atoken == null) { Slog.w(TAG_WM, "Attempted to add window with non-application token " + token + ". Aborting."); return WindowManagerGlobal.ADD_NOT_APP_TOKEN; } else if (atoken.removed) { Slog.w(TAG_WM, "Attempted to add window with exiting application token " + token + ". Aborting."); return WindowManagerGlobal.ADD_APP_EXITING; } else if (type == TYPE_APPLICATION_STARTING && atoken.startingWindow != null) { Slog.w(TAG_WM, "Attempted to add starting window to token with already existing" + " starting window"); return WindowManagerGlobal.ADD_DUPLICATE_ADD; } //其他各种窗口类型处理 } else if (rootType == TYPE_INPUT_METHOD) { ... }... //WindowState维护了所有窗口的信息,它是WMS实际管理的“窗口” //它与Z-Order密切相关(多个Window层叠布局),其属性mLayer 越大,窗口越靠前。 final WindowState win = new WindowState(this, session, client, token, parentWindow, appOp[0], seq, attrs, viewVisibility, session.mUid, session.mCanAddInternalSystemWindow); if (win.mDeathRecipient == null) { // Client has apparently died, so there is no reason to // continue. Slog.w(TAG_WM, "Adding window client " + client.asBinder() + " that is dead, aborting."); return WindowManagerGlobal.ADD_APP_EXITING; } ... origId = Binder.clearCallingIdentity(); //创建SurfaceSession,实现与SurfaceFlinger通信。参考2.9 简单说明下 win.attach(); //将WindowState对象加入到mWindowMap中 mWindowMap.put(client.asBinder(), win); win.initAppOpsState(); ... final AppWindowToken aToken = token.asAppWindowToken(); win.mToken.addWindow(win); win.applyAdjustForImeIfNeeded(); ... } ... return res; }
WMS通过WindowState对窗口进行管理、保存状态等。
添加窗口都需要指明其WindowToken;同时窗口需指明其DisplayContent 以确定显示到哪个屏幕设备。
具体请看上面注释,比较详细了。
看完,大致能明白窗口类型、WindowToken在窗口添加中的作用。了解到token的作用。
比如:若添加的时子窗口,则必须有父窗口,且窗口的层级最多为两层。WindowToken为null,可以明显看出那些情况不允许添加。添加的窗口时应用窗口时,WindowToken要是AppWindowToken。等等。
addWindow()暂时就说这些。
这个添加后的结果,通过res 最终反回到了 2.6:ViewRootImpl.setView() 中,根据结果 继续处理。
2.9:win.attach()
为什么 win.attach() 是创建与SurfaceFlinger通信的?简单了解下。
跟踪下去是创建了SurfaceSession对象,这个创建进入native,最终创建了一个与SurfaceFlinger通信的 SurfaceComposerClient。 因此,可以与SurfaceFlinger进行通信。
ViewRootImpl创建时 就创建的mSurface,mSurface是ViewRootImpl的成员变量,此时创建的Surface什么都没有,最后通过relayoutWindow()进入WMS 一步步向SurfaceFlinger发出请求。
这时几处相关代码。
//WindowState.java void attach() { if (localLOGV) Slog.v(TAG, "Attaching " + this + " token=" + mToken); mSession.windowAddedLocked(mAttrs.packageName); } //Session.java void windowAddedLocked(String packageName) { mPackageName = packageName; mRelayoutTag = "relayoutWindow: " + mPackageName; if (mSurfaceSession == null) { mSurfaceSession = new SurfaceSession(); ... } mNumWindow++; } //ViewRootImpl.java // These can be accessed by any thread, must be protected with a lock. // Surface can never be reassigned or cleared (use Surface.clear()). @UnsupportedAppUsage public final Surface mSurface = new Surface(); private final SurfaceControl mSurfaceControl = new SurfaceControl();
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