window类关系图
1.每个窗口都对应一个Activity对象,所以创建应用窗口首先是创建Activity.而启动Activity的任务由ActivityThread完成,本质是构造一个Activity对象.当ActivityThread接受到Ams发送的启动Activity通知时,会创建指定的Activity对象,Activity创建PhoneWindow类--DecorView类--创建相应的View或ViewGroup.创建完成后,Activity把创建好的界面显示到屏幕上,于是调用WindowManager类,WindowManager创建ViewRoot类和ViewRoot的内部类W.之后WindowManager在调用Wms提供的远程接口完成窗口的添加并显示在屏幕上
- 代码入口是ActivityThread.performLaunchActivity
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
ActivityInfo aInfo = r.activityInfo;
Activity activity = null;
try { //1.创建activity的对象,用classLoader从程序中装载指定Activity对应的Class文件
java.lang.ClassLoader cl = r.packageInfo.getClassLoader();
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent);
}
//2.创建 系统application,appContext appContext本质是ContextImpl
Application app = r.packageInfo.makeApplication(false, mInstrumentation);
Context appContext = createBaseContextForActivity(r, activity);
//3.为activity 配置内部变量.同时创建Window对象. this变量使Activity对象持有ActivityThread的引用.r 是ActivityClientRecord对象.
r.token是一个Binder,是Ams中的一个HistoryRecord对象. r.parent是一个父Activity,这种理念是为了允许把Activity嵌入到另一个Activity内部执行,
activity.attach(appContext, this, getInstrumentation(), r.token,
r.ident, app, r.intent, r.activityInfo, title, r.parent,
r.embeddedID, r.lastNonConfigurationInstances, config,
r.voiceInteractor);
int theme = r.activityInfo.getThemeResource(); //activity使用的主题
if (theme != 0) {
activity.setTheme(theme);
}
//4 这里会调用Activity的onCreate方法.
if (r.isPersistable()) {
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
//调用 onstart
if (!r.activity.mFinished) {
activity.performStart();
r.stopped = false;
}
//调用 onRestoreInstanceState
if (!r.activity.mFinished) {
if (r.isPersistable()) {
if (r.state != null || r.persistentState != null) {
mInstrumentation.callActivityOnRestoreInstanceState(activity, r.state,
r.persistentState);
}
} else if (r.state != null) {
mInstrumentation.callActivityOnRestoreInstanceState(activity, r.state);
}
}
//调用 onPostCreate
if (!r.activity.mFinished) {
activity.mCalled = false;
if (r.isPersistable()) {
mInstrumentation.callActivityOnPostCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnPostCreate(activity, r.state);
}
}
}
//ArrayMap结构
mActivities.put(r.token, r);
return activity;
}
//2.接着看步骤1.3的Actdivity 的attacth方法
//Activity 类
final void attach(Context context, ActivityThread aThread,
Instrumentation instr, IBinder token, int ident,
Application application, Intent intent, ActivityInfo info,
CharSequence title, Activity parent, String id,
NonConfigurationInstances lastNonConfigurationInstances,
Configuration config, IVoiceInteractor voiceInteractor) {
attachBaseContext(context); //新建的contextImpl赋值给mBase.
//1.创建Window.其实是创建了Window的子类PhoneWindow
mWindow = PolicyManager.makeNewWindow(this);
mWindow.setCallback(this); //表示Activity实现的Window的所有回调函数
//activity配置重要变量
mUiThread = Thread.currentThread();
mMainThread = aThread;
mInstrumentation = instr;
mToken = token; //Binder HistoryRecord类
mApplication = application;
mIntent = intent;
mComponent = intent.getComponent();
mActivityInfo = info;
mTitle = title;
mParent = parent; //activity
//2.给每个window分配WindowManager,其实是WindowManagerImpl.每个Window都对应一个WindowManagerImpl对象,
但WindowManger是一个重量级的类.他的真正实现是WindowManagerGlobal,而WindowManagerImpl只是一个装饰类,只是
把功能交给WindowManagerGlobal来实现
mWindow.setWindowManager(
(WindowManager)context.getSystemService(Context.WINDOW_SERVICE),
mToken, mComponent.flattenToString(),
(info.flags & ActivityInfo.FLAG_HARDWARE_ACCELERATED) != 0);
if (mParent != null) {//如果有父activity,就把父acitivty的window赋值给本Activity的window的container变量.
mWindow.setContainer(mParent.getWindow());
}
//activity 也持有WindowManager变量
mWindowManager = mWindow.getWindowManager();
}
//3.接下来是步骤1.4的 mInstrumentation.callActivityOnCreate(activity, r.state);
//1.Instrumentation类 他又调用Activity的performCreate方法
public void callActivityOnCreate(Activity activity, Bundle icicle) {
prePerformCreate(activity);
activity.performCreate(icicle);
postPerformCreate(activity);
}
//2.Activity 类 此时走到了onCreate ,我们会在onCreate中调用setContentView方法.接着看
final void performCreate(Bundle icicle) {
onCreate(icicle);
mActivityTransitionState.readState(icicle);
performCreateCommon();
}
//3.主要还是调用 getWindow().setContentView().而 getWindow()就是我们第一步生的Window类PhoneWindow对象.
public void setContentView(View view, ViewGroup.LayoutParams params) {
getWindow().setContentView(view, params);
initWindowDecorActionBar();
}
//4.phoneWindow类
@Override
public void setContentView(View view, ViewGroup.LayoutParams params) {
if (mContentParent == null) {
installDecor(); //5.初始化Decor,为Window创建界面.
} else if (!hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
mContentParent.removeAllViews();
}
//6.把要添加的view放在 mContentParent中.下边一个是有位移的添加方法,一个是直接添加.
mContentParnet其实就是我们setcontView是的那个view.他的id就是R.id.content.
我们平时定义的lauout.xml就成了mContentParnet 的子View
if (hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
view.setLayoutParams(params);
final Scene newScene = new Scene(mContentParent, view);
transitionTo(newScene);
} else {
mContentParent.addView(view, params);
}
//7.此时的callback就是2.1时创建Window时设置的回调.既Activity自己.
final Callback cb = getCallback();
if (cb != null && !isDestroyed()) {
cb.onContentChanged(); //调用activity的onContentChanged回调方法.
}
}
//4.看3.5的installDecor()方法
private void installDecor() {
if (mDecor == null) {
mDecor = generateDecor(); //1.创建一个DecorView.继承自FrameLayout,是窗口的最顶层View.
}
if (mContentParent == null) {
//2.这是我们自定义View的父View.
mContentParent = generateLayout(mDecor);
}
// Set up decor part of UI to ignore fitsSystemWindows if appropriate.
mDecor.makeOptionalFitsSystemWindows();//设置view适配系统窗口
//下边是根据设定的主题来设置标题栏样式.先不关注
...
}
//5.接着看 generateLayout()方法.
protected ViewGroup generateLayout(DecorView decor) {//decor是刚创建的DecorView
TypedArray a = getWindowStyle(); //1.指定Window样式
//2.requestFeature()启用窗体的扩展特性,用户可调用这个方法更改window样式
if (a.getBoolean(R.styleable.Window_windowNoTitle, false)) {
requestFeature(FEATURE_NO_TITLE);
} else if (a.getBoolean(R.styleable.Window_windowActionBar, false)) {
// Don't allow an action bar if there is no title.
requestFeature(FEATURE_ACTION_BAR);
}
...
//3.得到最终要使用的resource文件id.这个文件肯定包含一个id=content的FrameLayout,
int layoutResource;
int features = getLocalFeatures();
mDecor.startChanging();
//4.把该resource文件添加到Decorview里.它是DevorView的唯一view,同时赋值给变量mContentRoot
View in = mLayoutInflater.inflate(layoutResource, null);
decor.addView(in, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT));
mContentRoot = (ViewGroup) in;
//5.contentParent是mContentRoot的子view
ViewGroup contentParent = (ViewGroup)findViewById(ID_ANDROID_CONTENT);
if (contentParent == null) {
throw new RuntimeException("Window couldn't find content container view");
}
mDecor.finishChanging();
return contentParent;
}
//6.这样.window的窗口元素就设置完成,接下来通知Wms创建窗口.首先是Activity通知Ams,Ams处理完后调用Activity的makeVisible()方法,该方法和后续操作将把窗口真正添加进Wms中.
//Activity类
void makeVisible() {
if (!mWindowAdded) {
ViewManager wm = getWindowManager();//1.这里就是Activity内部的WindowManager类,具体其实是
WindowManagerImpl类,然后会调用WindowManagerGlobal的addView方法.
wm.addView(mDecor, getWindow().getAttributes());
mWindowAdded = true;
}
mDecor.setVisibility(View.VISIBLE);
}
//2.接着看WindowManagerGlobal的addView
//1.WindowMangerGlobal有三个变量.ArrayList mViews 每个View都将成为Wms所认为的一个窗口.
ArrayList mRoots 每个View都对应的一个ViewRootImpl对象,
ArrayList mParams 每个View对应的参数,
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow) {
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams)params;
ViewRootImpl root;
View panelParentView = null;
synchronized (mLock) {
// Start watching for system property changes.
if (mSystemPropertyUpdater == null) {
mSystemPropertyUpdater = new Runnable() {
@Override public void run() {
synchronized (mLock) {
for (int i = mRoots.size() - 1; i >= 0; --i) {
mRoots.get(i).loadSystemProperties(); //加载系统属性
}
}
}
};
SystemProperties.addChangeCallback(mSystemPropertyUpdater);
}
int index = findViewLocked(view, false); //2.如果该View已经添加过了.就不允许重复添加
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();
} else {
throw new IllegalStateException("View " + view
+ " has already been added to the window manager.");
}
// The previous removeView() had not completed executing. Now it has.
}
// If this is a panel window, then find the window it is being
// attached to for future reference.
if (wparams.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW &&
wparams.type <= WindowManager.LayoutParams.LAST_SUB_WINDOW) {
//3.1000-1999之间,是子窗口,需要找他的父窗口保存在panelParentView变量中
final int count = mViews.size();
for (int i = 0; i < count; i++) {
if (mRoots.get(i).mWindow.asBinder() == wparams.token) {
panelParentView = mViews.get(i);
}
}
}
//4.生成ViewRootImpl.用来沟通Wms和View,
root = new ViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
//5.把该view对应的变量添加到WindowManagerGlobal的三个对象中.
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
}
// do this last because it fires off messages to start doing things
try {
//6.完成最后的真正意义的添加动作 view是要添加的窗口 wParams是窗口的参数LayoutParams,panelParentView表示该窗口的父窗口,可以为空
root.setView(view, wparams, panelParentView);
} catch (RuntimeException e) {
throw e;
}
}
//接下来看ViewRootImpl的setView方法
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
synchronized (this) {
if (mView == null) {
mView = view;
//1.赋值attrs
mWindowAttributes.copyFrom(attrs);
if (mWindowAttributes.packageName == null) {
mWindowAttributes.packageName = mBasePackageName;
}
attrs = mWindowAttributes;
//2.配置参数
mSoftInputMode = attrs.softInputMode;
mWindowAttributesChanged = true;
mWindowAttributesChangesFlag = WindowManager.LayoutParams.EVERYTHING_CHANGED;
mAttachInfo.mRootView = view;
mAttachInfo.mScalingRequired = mTranslator != null;
mAttachInfo.mApplicationScale =
mTranslator == null ? 1.0f : mTranslator.applicationScale;
//3.如果有父窗口,把父窗口的token赋值给mAttachInfo
if (panelParentView != null) {
mAttachInfo.mPanelParentWindowToken
= panelParentView.getApplicationWindowToken();
}
mAdded = true;
int res; /* = WindowManagerImpl.ADD_OKAY; */
// 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.
//4.发出重绘请求,仅是发出一个异步请求,使Ui线程的下一个消息处理是界面重绘,使窗口在相应其他消息之前
先变得可见
requestLayout();
try { //5.通知Wms添加窗口,mWindowSession是WindowManagerGlobla的一个镜头变量,每个应用程序仅有一个mWindowSession对象,类型为IWindowSession,是一个Binder引用,对应Wms中的Session子类,Wms为每个应用程序分配一个Session对象.
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
getHostVisibility(), mDisplay.getDisplayId(),
mAttachInfo.mContentInsets, mInputChannel);
} catch (RemoteException {
throw new RuntimeException("Adding window failed", e);
}
}
至此,窗口的创建过程全部结束.
最后总结一下.第一步.是在ActivityThread的performLaunchActivity方法通过反射创建Activity启动的对象,同时为Activity创建添加一个ContextImpl对象,调用Activity.attach方法,然后执行Activity的onCreate,onStart.第二步Activity.attach中,为该Acitivity创建一个PhoneWindow(继承自Window)对象,这是一个轻量的对象,其实内部是由WindowManagerGlobal实现具体操作.第三步.在执行Activity的onCreate过程中,为activity创建DecorView,这是每个activity的顶层view.他里边包含一个id为content的view.就是我们调用setContentView的父view,第四部,Activity的view设置完成后.Activity通知Ams,Ams处理完后调用Activity的makeVisible()方法,该方法和后续操作将把窗口真正添加进Wms中.此时wms为创建一个ViewRootImpl类,用来沟通wms和view.最后.ViewRootImpl在把view进行一些处理后,通知Wms添加窗口