public class Activity extends ContextThemeWrapper
implements LayoutInflater.Factory2,
Window.Callback, KeyEvent.Callback,
OnCreateContextMenuListener, ComponentCallbacks2,
Window.OnWindowDismissedCallback,
ContentCaptureManager.ContentCaptureClient {
...
private Window mWindow;
}
mWindow在Activity#attach()方法中进行创建：
public class Activity {
//...
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, String referrer, IVoiceInteractor voiceInteractor,
Window window, ActivityConfigCallback activityConfigCallback, IBinder assistToken,
IBinder shareableActivityToken) {
...
mWindow = new PhoneWindow(this, window, activityConfigCallback);
mWindow.setWindowControllerCallback(mWindowControllerCallback);
mWindow.setCallback(this);
mWindow.setOnWindowDismissedCallback(this);
mWindow.getLayoutInflater().setPrivateFactory(this);
if (info.softInputMode != WindowManager.LayoutParams.SOFT_INPUT_STATE_UNSPECIFIED) {
mWindow.setSoftInputMode(info.softInputMode);
}
if (info.uiOptions != 0) {
mWindow.setUiOptions(info.uiOptions);
}
//...
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());
}
//...
}
}
每个Activity中的mWindowManager是一个WindowManagerImpl对象。一个应用中所有的Activity都是通过这个进程内唯一的WindowManagerGlobal对象和WMS通信。
public final class WindowManagerImpl implements WindowManager {
//...
@Override
public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
applyTokens(params);
mGlobal.addView(view, params, mContext.getDisplayNoVerify(), mParentWindow,
mContext.getUserId());
}
//...
}
WindowManagerGlobal的核心方法
public final class WindowManagerGlobal {
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow, int userId) {
//...
ViewRootImpl root;
View panelParentView = null;
synchronized (mLock) {
//...
int index = findViewLocked(view, false);
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.
}
IWindowSession windowlessSession = null;
// If there is a parent set, but we can't find it, it may be coming
// from a SurfaceControlViewHost hierarchy.
if (wparams.token != null && panelParentView == null) {
for (int i = 0; i < mWindowlessRoots.size(); i++) {
ViewRootImpl maybeParent = mWindowlessRoots.get(i);
if (maybeParent.getWindowToken() == wparams.token) {
windowlessSession = maybeParent.getWindowSession();
break;
}
}
}
if (windowlessSession == null) {
root = new ViewRootImpl(view.getContext(), display);
} else {
root = new ViewRootImpl(view.getContext(), display,
windowlessSession);
}
view.setLayoutParams(wparams);
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
// do this last because it fires off messages to start doing things
try {
root.setView(view, wparams, panelParentView, userId);
} catch (RuntimeException e) {
// BadTokenException or InvalidDisplayException, clean up.
if (index >= 0) {
removeViewLocked(index, true);
}
throw e;
}
}
}
}
ViewRootImpl
public final class ViewRootImpl implements ViewParent,
View.AttachInfo.Callbacks, ThreadedRenderer.DrawCallbacks,
AttachedSurfaceControl {
public ViewRootImpl(Context context, Display display) {
this(context, display, WindowManagerGlobal.getWindowSession(),
false /* useSfChoreographer */);
}
public ViewRootImpl(@UiContext Context context, Display display, IWindowSession session) {
this(context, display, session, false /* useSfChoreographer */);
}
public ViewRootImpl(@UiContext Context context, Display display, IWindowSession session,
boolean useSfChoreographer) {
mContext = context;
mWindowSession = session;
mDisplay = display;
mBasePackageName = context.getBasePackageName();
mThread = Thread.currentThread();
mLocation.fillInStackTrace();
mWidth = -1;
mHeight = -1;
mDirty = new Rect();
mWinFrame = new Rect();
mWindow = new W(this);
mLeashToken = new Binder();
mViewVisibility = View.GONE;
mTransparentRegion = new Region();
mPreviousTransparentRegion = new Region();
mFirst = true; // true for the first time the view is added
mPerformContentCapture = true; // also true for the first time the view is added
mAdded = false;
mAttachInfo = new View.AttachInfo(mWindowSession, mWindow, display, this, mHandler, this,
context);
//...
if (!sCompatibilityDone) {
sAlwaysAssignFocus = mTargetSdkVersion < Build.VERSION_CODES.P;
sCompatibilityDone = true;
}
loadSystemProperties();
mImeFocusController = new ImeFocusController(this);
AudioManager audioManager = mContext.getSystemService(AudioManager.class);
mFastScrollSoundEffectsEnabled = audioManager.areNavigationRepeatSoundEffectsEnabled();
mScrollCaptureRequestTimeout = SCROLL_CAPTURE_REQUEST_TIMEOUT_MILLIS;
mOnBackInvokedDispatcher = new WindowOnBackInvokedDispatcher(
context.getApplicationInfo().isOnBackInvokedCallbackEnabled());
}
}
其中IWindowSession是通过WindowManagerGlobal#getWindowSession()方法进行单例创建。对应WindowManagerService中的Session对象。
IWindowSession.aidl
interface IWindowSession {
int addToDisplay(IWindow window, in WindowManager.LayoutParams attrs,
in int viewVisibility, in int layerStackId, int requestedVisibleTypes,
out InputChannel outInputChannel, out InsetsState insetsState,
out InsetsSourceControl.Array activeControls, out Rect attachedFrame,
out float[] sizeCompatScale);
int addToDisplayAsUser(IWindow window, in WindowManager.LayoutParams attrs,
in int viewVisibility, in int layerStackId, in int userId, int requestedVisibleTypes,
out InputChannel outInputChannel, out InsetsState insetsState,
out InsetsSourceControl.Array activeControls, out Rect attachedFrame,
out float[] sizeCompatScale);
int addToDisplayWithoutInputChannel(IWindow window, in WindowManager.LayoutParams attrs,
in int viewVisibility, in int layerStackId, out InsetsState insetsState,
out Rect attachedFrame, out float[] sizeCompatScale);
@UnsupportedAppUsage
void remove(IWindow window);
//...
}
--> ActivityThread#handleResumeActivity(ActivityClientRecord r, boolean finalStateRequest,
boolean isForward, String reason)
--> WindowManagerImpl#addView(View view, ViewGroup.LayoutParams params)
--> WindowManagerGlobal#addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow, int userId)
--> ViewRootImpl#setView(View view, WindowManager.LayoutParams attrs, View panelParentView,
int userId)
--> IWindowSession#addToDisplayAsUser(IWindow window, WindowManager.LayoutParams attrs,
int viewVisibility, int displayId, int userId, InsetsVisibilities requestedVisibilities,
InputChannel outInputChannel, InsetsState outInsetsState,
InsetsSourceControl[] outActiveControls)
--> Session#addToDisplayAsUser(IWindow window, WindowManager.LayoutParams attrs,
int viewVisibility, int displayId, int userId, InsetsVisibilities requestedVisibilities,
InputChannel outInputChannel, InsetsState outInsetsState,
InsetsSourceControl[] outActiveControls
--> WindowManagerService#addWindow(Session session, IWindow client, LayoutParams attrs, int viewVisibility,
int displayId, int requestUserId, InsetsVisibilities requestedVisibilities,
InputChannel outInputChannel, InsetsState outInsetsState,
InsetsSourceControl[] outActiveControls)
其中IWindowSession#addDisplayToUser()方法的第一个参数为IWindow类型，对应的Binder Server端实例为ViewRootImpl中的mWindow。
DecorView
DecorView 是一个 FrameLayout 的子类，作为应用程序窗口的根视图，包含了整个应用程序界面的视图层次结构。DecorView 的内容包括应用程序的标题栏、内容区域、状态栏等。它是整个窗口中所有视图的容器。
在 PhoneWindow 中，当 Activity 启动时，系统会创建 PhoneWindow，并在其中创建 DecorView 作为窗口的根视图。DecorView 通过 setContentView 方法加载应用程序的布局资源。
DecorView通过PhoneWindow的getDecorView()方法获取，如果mDecor为空，则通过PhoneWindow#installDecor()进行创建。
