Activity创建Window和View分析
2020-12-13 04:47
标签：android style blog http java 使用 一.Activity启动 转自：http://blog.csdn.net/ljsbuct/article/details/7094575 Activity创建Window和View分析,搜素材,soscw.com Activity创建Window和View分析 标签：android style blog http java 使用 原文地址：http://www.cnblogs.com/chyl411/p/3850615.html
Activity由ActivityThread负责启动。 ActivityThread的分析将在《ActivityThread分析》中，在此，只需要知道创建activity的入口在ActivityThread就行，不影响以下的分析。
ActivityThread.java
private final Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
Activity activity = null;
try {
java.lang.ClassLoader cl = r.packageInfo.getClassLoader();
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent);
r.intent.setExtrasClassLoader(cl);
if (r.state != null) {
r.state.setClassLoader(cl);
}
} catch (Exception e) {
if (!mInstrumentation.onException(activity, e)) {
throw new RuntimeException(
"Unable to instantiate activity " + component
+ ": " + e.toString(), e);
}
}
return activity;
}
二。调用Activity的attach方法。
ActivityThread.java
private final Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
ContextImpl appContext = new ContextImpl();
appContext.init(r.packageInfo, r.token, this);
appContext.setOuterContext(activity);
CharSequence title = r.activityInfo.loadLabel(appContext.getPackageManager());
Configuration config = new Configuration(mConfiguration);
if (DEBUG_CONFIGURATION) Slog.v(TAG, "Launching activity "
+ r.activityInfo.name + " with config " + config);
activity.attach(appContext, this, getInstrumentation(), r.token,
r.ident, app, r.intent, r.activityInfo, title, r.parent,
r.embeddedID, r.lastNonConfigurationInstance,
r.lastNonConfigurationChildInstances, config);
}
三。Activity的attach实现
1.attach的实现
Activity.java //Activity implement Window.Callback
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,
Object lastNonConfigurationInstance,
HashMap
Configuration config) {
attachBaseContext(context); //ContextThemeWrapper中实现，赋值给mBase
mWindow = PolicyManager.makeNewWindow(this); //创建window，实际上是一个PhoneWindow对象
mWindow.setCallback(this); //设置Window.Callback，因为Activity implement Window.Callback
mWindow.setWindowManager(null, mToken, mComponent.flattenToString());
mWindowManager = mWindow.getWindowManager();
}
2.PolicyManager.makeNewWindow实现
(1).PolicyManager.java
private static final String POLICY_IMPL_CLASS_NAME =
"com.android.internal.policy.impl.Policy";
private static final IPolicy sPolicy;
static {
// Pull in the actual implementation of the policy at run-time
Class policyClass = Class.forName(POLICY_IMPL_CLASS_NAME);
sPolicy = (IPolicy)policyClass.newInstance();
}
public static Window makeNewWindow(Context context) {
return sPolicy.makeNewWindow(context);
}
(2).Policy.java //Policy implements IPolicy
public PhoneWindow makeNewWindow(Context context) {
return new PhoneWindow(context);
}
3.设置WindowManager
mWindow.setWindowManager(null, mToken, mComponent.flattenToString()); //为Window中的WindowManager赋值
mWindowManager = mWindow.getWindowManager(); //为Acitivity中的WindowManager赋值
WindowManager只是一个interface，实现类有两个：Window.LocalWindowManager和WindowManagerImpl。
(1).Window.LocalWindowManager实现，只是对WindowManagerImpl的封装调用。
private class LocalWindowManager implements WindowManager {
private final WindowManager mWindowManager;
LocalWindowManager(WindowManager wm) {
mWindowManager = wm;
}
public final void addView(View view, ViewGroup.LayoutParams params) {
//some code to check params here
mWindowManager.addView(view, params);
}
public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
mWindowManager.updateViewLayout(view, params);
}
public final void removeView(View view) {
mWindowManager.removeView(view);
}
public final void removeViewImmediate(View view) {
mWindowManager.removeViewImmediate(view);
}
}
(2).Window.setWindowManager实现分析
public void setWindowManager(WindowManager wm, IBinder appToken, String appName) {
if (wm == null) {
wm = WindowManagerImpl.getDefault();
}
mWindowManager = new LocalWindowManager(wm);
}
四。回调Activity的onCreate方法。
(1). ActivityThread.java
private final Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
(2). Instrumentation.java
public void callActivityOnCreate(Activity activity, Bundle icicle) {
activity.onCreate(icicle);
}
五。Activity中setContentView(int layout)分析
Activity.java
public void setContentView(int layoutResID) {
getWindow().setContentView(layoutResID);
}
public Window getWindow() {
return mWindow; //mWindow = PolicyManager.makeNewWindow(this);
}
六。Window中setContentView(int layout)分析
(1)PhoneWindow.java //因为Window是个abstract class， mWindow实际上是一个PhoneWindow对象
public void setContentView(int layoutResID) {
if (mContentParent == null) {
installDecor();
} else {
mContentParent.removeAllViews();
}
mLayoutInflater.inflate(layoutResID, mContentParent);
final Callback cb = getCallback();
if (cb != null) {
cb.onContentChanged();
}
}
(2) installDecor()分析 //PhoneWindow.java中
private void installDecor() {
if (mDecor == null) {
mDecor = generateDecor();
}
if (mContentParent == null) {
mContentParent = generateLayout(mDecor);
}
}
mDecor： class DecorView extends FrameLayout
mContentParent： class ViewGroup
(3)generateDecor()分析
protected DecorView generateDecor() {
return new DecorView(getContext(), -1);
}
DecorView:继承自FrameLayout，可以理解成窗口修饰，这个窗口修饰可以有各种style，比如标题栏，显示进度条等。常见的窗口修饰的layout路径为：frameworks/base/core/res/res/layout，比如R.layout.dialog_title_icons, R.layout.screen_title_icons.
(4)generateLayout()分析
protected ViewGroup generateLayout(DecorView decor) {
// Inflate the window decor.
int layoutResource;
if ((features & ((1 if (mIsFloating) {
layoutResource = com.android.internal.R.layout.dialog_title_icons;
} else {
layoutResource = com.android.internal.R.layout.screen_title_icons;
}
} else if ((features & ((1 layoutResource = com.android.internal.R.layout.screen_progress;
} else if ((features & (1 if (mIsFloating) {
layoutResource = com.android.internal.R.layout.dialog_custom_title;
} else {
layoutResource = com.android.internal.R.layout.screen_custom_title;
}
} else if ((features & (1 if (mIsFloating) {
layoutResource = com.android.internal.R.layout.dialog_title;
} else {
layoutResource = com.android.internal.R.layout.screen_title;
}
} else {
layoutResource = com.android.internal.R.layout.screen_simple;
}
View in = mLayoutInflater.inflate(layoutResource, null);
decor.addView(in, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT));
ViewGroup contentParent = (ViewGroup)findViewById(ID_ANDROID_CONTENT);
if (contentParent == null) {
throw new RuntimeException("Window couldn‘t find content container view");
}
return contentParent;
}
DecorView的样式的定义：第一种是在Activity中onCreate中调用requestFeature（）。另一种是在AndroidManifest.xml中配置android:theme="xxx".
DecorView添加View：generateLayout的前部分代码，就是确定DecorView的样式，然后inflate这个layout文件，再调用DecorView.addView()添加到DecorView上。
mContentParent赋值：窗口修饰的layout中必须有一个FrameLayout，id为ID_ANDROID_CONTENT（实际上id=content），将这个FrameLayout赋值给mContentParent。
(5)添加窗口内容到mContentParent。
mLayoutInflater.inflate(layoutResID, mContentParent);
将activity传入的layoutRes添加到窗口装饰中。
(6)Window.Callback回调
final Callback cb = getCallback(); //Activity实现了Window.Callback接口，并且在创建PhoneWindow后，调用mWindow.setCallback(this)
if (cb != null) {
cb.onContentChanged();
}
七。通知WmS，显示DecorView
Activity准备好后会通知AmS，AmS通过一些条件判断，回调Activity的makeVisible().
(1.) Activity.java
public void setVisible(boolean visible) {
if (mVisibleFromClient != visible) {
mVisibleFromClient = visible;
if (mVisibleFromServer) {
if (visible) makeVisible();
else mDecor.setVisibility(View.INVISIBLE);
}
}
}
void makeVisible() {
if (!mWindowAdded) {
ViewManager wm = getWindowManager();
wm.addView(mDecor, getWindow().getAttributes()); //通过WindowManager将DecorView添加到window。
mWindowAdded = true;
}
mDecor.setVisibility(View.VISIBLE);
}
public Window getWindow() {
return mWindow;
}
(2.) Window.java
public final WindowManager.LayoutParams getAttributes() {
return mWindowAttributes;
}
private final WindowManager.LayoutParams mWindowAttributes =
new WindowManager.LayoutParams();
(3.) WindowManager.LayoutParams
public LayoutParams() {
super(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
type = TYPE_APPLICATION;
format = PixelFormat.OPAQUE;
}
(4.)Window.LocalWindowManager
wm.addView(mDecor, getWindow().getAttributes())分析
这个wm是LocalWindowManager，是对WindowManagerImpl的封装，目地是对params进行一些校验后，再调用WindowManagerImpl的addView。
校验params：
if (wp.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW &&
wp.type } else {
}
八。WindowManagerImpl.addView分析
方法：addView(View view, ViewGroup.LayoutParams params, boolean nest)；
class WindowManagerImpl extends WindowManager， interface WindowManager extends ViewManager
3个成员变量：
private View[] mViews;//每个view对象都将成为WmS所认为的一个窗口
private ViewRoot[] mRoots;//每个view对应一个ViewRoot
private WindowManager.LayoutParams[] mParams;//对应mViews的每个view的param
(1.)检查view是否已经添加过，不允许重复添加
int index = findViewLocked(view, false);
if (index >= 0) {
if (!nest) {
throw new IllegalStateException("View " + view
+ " has already been added to the window manager.");
}
root = mRoots[index];
root.mAddNesting++;
// Update layout parameters.
view.setLayoutParams(wparams);
root.setLayoutParams(wparams, true);
return;
}
(2.)检查窗口类型是否为sub window。如果是，则找到它的父窗口，并保存在临时变量panelParentView中，为下面调用ViewRoot的setView使用。
if (wparams.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW &&
wparams.type final int count = mViews != null ? mViews.length : 0;
for (int i=0; i
panelParentView = mViews[i];
}
}
}
(3.)创建一个新的ViewRoot，上文说过每个view都对应一个ViewRoot。
root = new ViewRoot(view.getContext());
root.mAddNesting = 1;
ViewRoot的构造方法：
public ViewRoot(Context context) {
super();
// Initialize the statics when this class is first instantiated. This is
// done here instead of in the static block because Zygote does not
// allow the spawning of threads.
getWindowSession(context.getMainLooper()); //init static IWindowSession sWindowSession;
mThread = Thread.currentThread();
mLocation = new WindowLeaked(null);
mLocation.fillInStackTrace();
mWidth = -1;
mHeight = -1;
mDirty = new Rect();
mTempRect = new Rect();
mVisRect = new Rect();
mWinFrame = new Rect();
mWindow = new W(this, context); // class W extends IWindow.Stub
mInputMethodCallback = new InputMethodCallback(this);
mViewVisibility = View.GONE;
mTransparentRegion = new Region();
mPreviousTransparentRegion = new Region();
mFirst = true; // true for the first time the view is added
mAdded = false;
mAttachInfo = new View.AttachInfo(sWindowSession, mWindow, this, this);
mViewConfiguration = ViewConfiguration.get(context);
mDensity = context.getResources().getDisplayMetrics().densityDpi;
}
(4.)将view，root和param添加到上面的3个数组中。
if (mViews == null) {
index = 1;
mViews = new View[1];
mRoots = new ViewRoot[1];
mParams = new WindowManager.LayoutParams[1];
} else {
index = mViews.length + 1;
Object[] old = mViews; //保存原来的数组
mViews = new View[index]; //新建一个数组，长度+1
System.arraycopy(old, 0, mViews, 0, index-1); //将原来的数组copy到新建的数组中
old = mRoots;
mRoots = new ViewRoot[index];
System.arraycopy(old, 0, mRoots, 0, index-1);
old = mParams;
mParams = new WindowManager.LayoutParams[index];
System.arraycopy(old, 0, mParams, 0, index-1);
}
index--;
mViews[index] = view;
mRoots[index] = root;
mParams[index] = wparams;
(5.)调用ViewRoot的setView方法，完成最后的添加工作。
九。ViewRoot的setView分析
参数意义：
view： WindowManagerImpl中mViews数组中的元素，也就是新建的窗口界面
attrs：窗口参数，描述窗口的风格，大小，位置。attrs中的token变量指明了该窗口和activity的关系。
panelParentView：view的父窗口
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
synchronized (this) {
if (mView == null) {
mView = view;//给成员变量赋值。
mWindowAttributes.copyFrom(attrs);//给成员变量赋值。
attrs = mWindowAttributes;//给成员变量赋值。
………………………………
mSoftInputMode = attrs.softInputMode;//给成员变量赋值。
mWindowAttributesChanged = true;//给成员变量赋值。
mAttachInfo.mRootView = view;//给成员变量赋值。
if (panelParentView != null) {
mAttachInfo.mPanelParentWindowToken
= panelParentView.getApplicationWindowToken();
}
………………………………
requestLayout(); //发出重绘请求，使该 在相应消息前变的可见
………………………………
try {
//通知WmS，添加窗口
res = sWindowSession.add(mWindow, mWindowAttributes,
getHostVisibility(), mAttachInfo.mContentInsets,
mInputChannel);
} catch (RemoteException e) {
}
}
}
}
十。sWindowSession.add分析
（1）IWindowSession是一个aidl接口，实现类是在WmS中：class Session extends IWindowSession.Stub
（2）sWindowSession的初始化： //static IWindowSession sWindowSession;
public static IWindowSession getWindowSession(Looper mainLooper) {
synchronized (mStaticInit) {
if (!mInitialized) {
try {
InputMethodManager imm = InputMethodManager.getInstance(mainLooper);
sWindowSession = IWindowManager.Stub.asInterface(
ServiceManager.getService("window")) //先获得WmS
.openSession(imm.getClient(), imm.getInputContext()); //再通过WmS获取分配的IWindowSession
mInitialized = true;
} catch (RemoteException e) {
}
}
return sWindowSession;
}
}
（3）sWindowSession为static，WmS为每个进程只分配1个。调用sWindowSession.add是app请求WmS添加窗口的唯一入口。
总结：至此，从客户端的角度讲，已经完成了窗口创建的全部工作。
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