Window，WindowManager学习总结
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一、提到WindowManager，那么很多时候我们会在什么地方用到它呢，我先写一个Demo吧。是一个浮动窗体的，在网上能找到很多。
public class WindowmanagerDemo extends AppCompatActivity implements View.OnClickListener { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_windowmanager); findViewById(R.id.show).setOnClickListener(this); findViewById(R.id.hide).setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()){ case R.id.show:// Intent intent = new Intent(this,ServiceFload.class); startService(intent); break; case R.id.hide:// Intent intent1 = new Intent(this,ServiceFload.class); stopService(intent1); break; } }}利用Service向Window调加view，因为Acitivity迟早会消失的，这样，浮层就会消失；滑动时间处理的很简单，可以细化。public class ServiceFload extends Service { Button mFloatingButton ; WindowManager.LayoutParams mLayoutParams; WindowManager mWndowManager; @Nullable @Override public IBinder onBind(Intent intent) { return null; } @Override public void onCreate() { super.onCreate(); mWndowManager = (WindowManager)getApplication().getSystemService(getApplication().WINDOW_SERVICE); mFloatingButton = new Button(this); mFloatingButton.setText("button"); mLayoutParams = new WindowManager.LayoutParams(); mLayoutParams.type = WindowManager.LayoutParams.TYPE_PHONE; mLayoutParams.format = PixelFormat.RGBA_8888; mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE; mLayoutParams.gravity = Gravity.LEFT | Gravity.TOP; mLayoutParams.x = 100; mLayoutParams.y = 100; mLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT; mLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT; mWndowManager.addView(mFloatingButton,mLayoutParams); mFloatingButton.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_MOVE: mLayoutParams.x = (int) event.getRawX(); mLayoutParams.y = (int) event.getRawY(); mWndowManager.updateViewLayout(mFloatingButton, mLayoutParams); break; default: break; } return false; } }); } @Override public void onDestroy() { super.onDestroy(); mWndowManager.removeView(mFloatingButton); }}二、Window表示一个窗口的意思，在平时开发中不常使用，但有时候还会用到。其实不管是Activity、Dialog、还是Toast他们的视图实际上都是附加在Window上的。然后根据demo介绍下WindowManager.LayoutParams的常用参数
flags：
FLAG_NOT_FOCUSABLE：表示Window不需要获取焦点，也不需要接收各种输入事件，此同时会启动FLAG_NOT_TOUCH_MODAL，最终事件会直接传递给下层具有焦点的Window。
FLAG_NOT_TOUCH_MODAL：在此模式下，系统会将当前Window区域外的单击事件传递给底层的window，当前Window区域内的单击事件则自己处理，这个标记很重要，一般来说，都要开启这个标记，因为不开启这个标记，其他Window就获取不到单击事件了。
type：表示Window的类型，总共有三种：应用Window，子Window和系统Window。
应用Window对应着一个Activity，子Window不能单独存在，必须附属在一个父Window之中，比如一些Dialog就是一个子Window。系统Window创建是需要声明权限的，我们常见的Toast和系统状态栏都是系统的Window。
Window是分层的，应用Window的层级是1~99，子Window的层级是1000~1999，系统Window的层级范围是2000~2999。这些参数都是对应着type参数的，层级越大越在Window的上层。常用的WindowManager.LayoutParams.TYPE_PHONE其实还很多。
更多详解请参考我在网上找的博客：http://blog.csdn.net/i_lovefish/article/details/8050025
常用的WindowManager所提供的功能：addView(添加view)，updateViewLayout(更新view)，removeView(移除view)，getDefaultDisplay(获取显示器)
三、Window的内部机制
首先先说个概况：WindowManager是将Window和View结合的，但WindowManager可以说只是个桥梁，真正使他们结合的是WindowManagerService。
1.Window的添加过程：
Window的添加需要通过WindowManager的addView方法来实现，当我们通过(WindowManager)getApplication().getSystemService(getApplication().WINDOW_SERVICE)获取WindowManager的时候其实返回的是WindowManagerImpl；WindowManager是一个接口，WindowManagerImpl才是它真正的实现：
ContextWrapper中：
@Override public Object getSystemService(String name) { return mBase.getSystemService(name); }ContextImpl中：@Override public Object getSystemService(String name) { return SystemServiceRegistry.getSystemService(this, name); }SystemServiceRegistry中：(此处省去其他代码，大家可以通过搜索WINDOW_SERVICE定位)，所以可以证明使用的是WindowManagerImpl的addviewregisterService(Context.WINDOW_SERVICE, WindowManager.class, new CachedServiceFetcher<WindowManager>() { @Override public WindowManager createService(ContextImpl ctx) { return new WindowManagerImpl(ctx.getDisplay()); }});WindowManagerImpl中的代码不多，我们可以很快捷的看到我们平时用的方法。public final class WindowManagerImpl implements WindowManager { private final WindowManagerGlobal mGlobal = WindowManagerGlobal.getInstance(); private final Display mDisplay; private final Window mParentWindow; private IBinder mDefaultToken; public WindowManagerImpl(Display display) { this(display, null); } private WindowManagerImpl(Display display, Window parentWindow) { mDisplay = display; mParentWindow = parentWindow; } public WindowManagerImpl createLocalWindowManager(Window parentWindow) { return new WindowManagerImpl(mDisplay, parentWindow); } public WindowManagerImpl createPresentationWindowManager(Display display) { return new WindowManagerImpl(display, mParentWindow); } /** * Sets the window token to assign when none is specified by the client or * available from the parent window. * * @param token The default token to assign. */ public void setDefaultToken(IBinder token) { mDefaultToken = token; } @Override public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) { applyDefaultToken(params); mGlobal.addView(view, params, mDisplay, mParentWindow); } @Override public void updateViewLayout(@NonNull View view, @NonNull ViewGroup.LayoutParams params) { applyDefaultToken(params); mGlobal.updateViewLayout(view, params); } private void applyDefaultToken(@NonNull ViewGroup.LayoutParams params) { // Only use the default token if we don't have a parent window. if (mDefaultToken != null && mParentWindow == null) { if (!(params instanceof WindowManager.LayoutParams)) { throw new IllegalArgumentException("Params must be WindowManager.LayoutParams"); } // Only use the default token if we don't already have a token. final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params; if (wparams.token == null) { wparams.token = mDefaultToken; } } } @Override public void removeView(View view) { mGlobal.removeView(view, false); } @Override public void removeViewImmediate(View view) { mGlobal.removeView(view, true); } @Override public Display getDefaultDisplay() { return mDisplay; }}代码中我们看到WindowManagerImpl并没有什么做什么，而是直接交给了WindowManagerGlobal，public void addView(View view, ViewGroup.LayoutParams params, Display display, Window parentWindow) {//检查参数是否合法 if (view == null) { throw new IllegalArgumentException("view must not be null"); } if (display == null) { throw new IllegalArgumentException("display must not be null"); } if (!(params instanceof WindowManager.LayoutParams)) { throw new IllegalArgumentException("Params must be WindowManager.LayoutParams"); }//如果是子Window还需要调整一些参数 final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params; if (parentWindow != null) { parentWindow.adjustLayoutParamsForSubWindow(wparams); } else { // If there's no parent, then hardware acceleration for this view is // set from the application's hardware acceleration setting. final Context context = view.getContext(); if (context != null && (context.getApplicationInfo().flags & ApplicationInfo.FLAG_HARDWARE_ACCELERATED) != 0) { wparams.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED; } } 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(); } } } }; SystemProperties.addChangeCallback(mSystemPropertyUpdater); } 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. } // 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) { final int count = mViews.size(); for (int i = 0; i < count; i++) { if (mRoots.get(i).mWindow.asBinder() == wparams.token) { panelParentView = mViews.get(i); } } } //创建ViewRootImpl，并将View添加到列表中 root = new ViewRootImpl(view.getContext(), display); view.setLayoutParams(wparams); //private final ArrayList<View> mViews = new ArrayList<View>();存储的是所有Window对应的View mViews.add(view); //private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>();存储的是所有Window对应的ViewRootImpl mRoots.add(root); //private final ArrayList<WindowManager.LayoutParams> mParams =new ArrayList<WindowManager.LayoutParams>();存储的对应的参数 mParams.add(wparams); } // do this last because it fires off messages to start doing things try { root.setView(view, wparams, panelParentView); } catch (RuntimeException e) { // BadTokenException or InvalidDisplayException, clean up. synchronized (mLock) { final int index = findViewLocked(view, false); if (index >= 0) { removeViewLocked(index, true); } } throw e; } }然后通过ViewRootImpl的setView来更新界面并完成Window的添加过程：在setView方法中通过requestLayout完成异步刷新请求，scheduleTraversals()去绘制View：
@Override public void requestLayout() { if (!mHandlingLayoutInLayoutRequest) { checkThread(); mLayoutRequested = true; scheduleTraversals(); } }然后在setView内部会通过WindowSession完成Window的添加过程，它真正的实现类是Session：
try { mOrigWindowType = mWindowAttributes.type; mAttachInfo.mRecomputeGlobalAttributes = true; collectViewAttributes(); res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes, getHostVisibility(), mDisplay.getDisplayId(), mAttachInfo.mContentInsets, mAttachInfo.mStableInsets, mAttachInfo.mOutsets, mInputChannel); }Session的内部是通过WindowManagerService来完成Window的添加的@Override public int addToDisplay(IWindow window, int seq, WindowManager.LayoutParams attrs, int viewVisibility, int displayId, Rect outContentInsets, Rect outStableInsets, Rect outOutsets, InputChannel outInputChannel) { return mService.addWindow(this, window, seq, attrs, viewVisibility, displayId, outContentInsets, outStableInsets, outOutsets, outInputChannel); }WindowManagerService的addWindow方法实现如下(代码较长)：
public int addWindow(Session session, IWindow client, int seq, WindowManager.LayoutParams attrs, int viewVisibility, int displayId, Rect outContentInsets, Rect outStableInsets, Rect outOutsets, InputChannel outInputChannel) { int[] appOp = new int[1]; int res = mPolicy.checkAddPermission(attrs, appOp); if (res != WindowManagerGlobal.ADD_OKAY) { return res; } boolean reportNewConfig = false; WindowState attachedWindow = null; long origId; final int type = attrs.type; synchronized(mWindowMap) { if (!mDisplayReady) { throw new IllegalStateException("Display has not been initialialized"); } final DisplayContent displayContent = getDisplayContentLocked(displayId); if (displayContent == null) { Slog.w(TAG, "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, "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, "Window " + client + " is already added"); return WindowManagerGlobal.ADD_DUPLICATE_ADD; } if (type >= FIRST_SUB_WINDOW && type <= LAST_SUB_WINDOW) { attachedWindow = windowForClientLocked(null, attrs.token, false); if (attachedWindow == null) { Slog.w(TAG, "Attempted to add window with token that is not a window: " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN; } if (attachedWindow.mAttrs.type >= FIRST_SUB_WINDOW && attachedWindow.mAttrs.type <= LAST_SUB_WINDOW) { Slog.w(TAG, "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, "Attempted to add private presentation window to a non-private display. Aborting."); return WindowManagerGlobal.ADD_PERMISSION_DENIED; } boolean addToken = false; WindowToken token = mTokenMap.get(attrs.token); if (token == null) { if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) { Slog.w(TAG, "Attempted to add application window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (type == TYPE_INPUT_METHOD) { Slog.w(TAG, "Attempted to add input method window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (type == TYPE_VOICE_INTERACTION) { Slog.w(TAG, "Attempted to add voice interaction window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (type == TYPE_WALLPAPER) { Slog.w(TAG, "Attempted to add wallpaper window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (type == TYPE_DREAM) { Slog.w(TAG, "Attempted to add Dream window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } if (type == TYPE_ACCESSIBILITY_OVERLAY) { Slog.w(TAG, "Attempted to add Accessibility overlay window with unknown token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } token = new WindowToken(this, attrs.token, -1, false); addToken = true; } else if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) { AppWindowToken atoken = token.appWindowToken; if (atoken == null) { Slog.w(TAG, "Attempted to add window with non-application token " + token + ". Aborting."); return WindowManagerGlobal.ADD_NOT_APP_TOKEN; } else if (atoken.removed) { Slog.w(TAG, "Attempted to add window with exiting application token " + token + ". Aborting."); return WindowManagerGlobal.ADD_APP_EXITING; } if (type == TYPE_APPLICATION_STARTING && atoken.firstWindowDrawn) { // No need for this guy! if (localLOGV) Slog.v( TAG, "**** NO NEED TO START: " + attrs.getTitle()); return WindowManagerGlobal.ADD_STARTING_NOT_NEEDED; } } else if (type == TYPE_INPUT_METHOD) { if (token.windowType != TYPE_INPUT_METHOD) { Slog.w(TAG, "Attempted to add input method window with bad token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } } else if (type == TYPE_VOICE_INTERACTION) { if (token.windowType != TYPE_VOICE_INTERACTION) { Slog.w(TAG, "Attempted to add voice interaction window with bad token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } } else if (type == TYPE_WALLPAPER) { if (token.windowType != TYPE_WALLPAPER) { Slog.w(TAG, "Attempted to add wallpaper window with bad token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } } else if (type == TYPE_DREAM) { if (token.windowType != TYPE_DREAM) { Slog.w(TAG, "Attempted to add Dream window with bad token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } } else if (type == TYPE_ACCESSIBILITY_OVERLAY) { if (token.windowType != TYPE_ACCESSIBILITY_OVERLAY) { Slog.w(TAG, "Attempted to add Accessibility overlay window with bad token " + attrs.token + ". Aborting."); return WindowManagerGlobal.ADD_BAD_APP_TOKEN; } } else if (token.appWindowToken != null) { Slog.w(TAG, "Non-null appWindowToken for system window of type=" + type); // It is not valid to use an app token with other system types; we will // instead make a new token for it (as if null had been passed in for the token). attrs.token = null; token = new WindowToken(this, null, -1, false); addToken = true; } WindowState win = new WindowState(this, session, client, token, attachedWindow, appOp[0], seq, attrs, viewVisibility, displayContent); if (win.mDeathRecipient == null) { // Client has apparently died, so there is no reason to // continue. Slog.w(TAG, "Adding window client " + client.asBinder() + " that is dead, aborting."); return WindowManagerGlobal.ADD_APP_EXITING; } if (win.getDisplayContent() == null) { Slog.w(TAG, "Adding window to Display that has been removed."); return WindowManagerGlobal.ADD_INVALID_DISPLAY; } mPolicy.adjustWindowParamsLw(win.mAttrs); win.setShowToOwnerOnlyLocked(mPolicy.checkShowToOwnerOnly(attrs)); res = mPolicy.prepareAddWindowLw(win, attrs); if (res != WindowManagerGlobal.ADD_OKAY) { return res; } if (outInputChannel != null && (attrs.inputFeatures & WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHANNEL) == 0) { String name = win.makeInputChannelName(); InputChannel[] inputChannels = InputChannel.openInputChannelPair(name); win.setInputChannel(inputChannels[0]); inputChannels[1].transferTo(outInputChannel); mInputManager.registerInputChannel(win.mInputChannel, win.mInputWindowHandle); } // From now on, no exceptions or errors allowed! res = WindowManagerGlobal.ADD_OKAY; origId = Binder.clearCallingIdentity(); if (addToken) { mTokenMap.put(attrs.token, token); } win.attach(); mWindowMap.put(client.asBinder(), win); if (win.mAppOp != AppOpsManager.OP_NONE) { int startOpResult = mAppOps.startOpNoThrow(win.mAppOp, win.getOwningUid(), win.getOwningPackage()); if ((startOpResult != AppOpsManager.MODE_ALLOWED) && (startOpResult != AppOpsManager.MODE_DEFAULT)) { win.setAppOpVisibilityLw(false); } } if (type == TYPE_APPLICATION_STARTING && token.appWindowToken != null) { token.appWindowToken.startingWindow = win; if (DEBUG_STARTING_WINDOW) Slog.v (TAG, "addWindow: " + token.appWindowToken + " startingWindow=" + win); } boolean imMayMove = true; if (type == TYPE_INPUT_METHOD) { win.mGivenInsetsPending = true; mInputMethodWindow = win; addInputMethodWindowToListLocked(win); imMayMove = false; } else if (type == TYPE_INPUT_METHOD_DIALOG) { mInputMethodDialogs.add(win); addWindowToListInOrderLocked(win, true); moveInputMethodDialogsLocked(findDesiredInputMethodWindowIndexLocked(true)); imMayMove = false; } else { addWindowToListInOrderLocked(win, true); if (type == TYPE_WALLPAPER) { mLastWallpaperTimeoutTime = 0; displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER; } else if ((attrs.flags&FLAG_SHOW_WALLPAPER) != 0) { displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER; } else if (mWallpaperTarget != null && mWallpaperTarget.mLayer >= win.mBaseLayer) { // If there is currently a wallpaper being shown, and // the base layer of the new window is below the current // layer of the target window, then adjust the wallpaper. // This is to avoid a new window being placed between the // wallpaper and its target. displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER; } } final WindowStateAnimator winAnimator = win.mWinAnimator; winAnimator.mEnterAnimationPending = true; winAnimator.mEnteringAnimation = true; if (displayContent.isDefaultDisplay) { mPolicy.getInsetHintLw(win.mAttrs, mRotation, outContentInsets, outStableInsets, outOutsets); } else { outContentInsets.setEmpty(); outStableInsets.setEmpty(); } if (mInTouchMode) { res |= WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE; } if (win.mAppToken == null || !win.mAppToken.clientHidden) { res |= WindowManagerGlobal.ADD_FLAG_APP_VISIBLE; } mInputMonitor.setUpdateInputWindowsNeededLw(); boolean focusChanged = false; if (win.canReceiveKeys()) { focusChanged = updateFocusedWindowLocked(UPDATE_FOCUS_WILL_ASSIGN_LAYERS, false /*updateInputWindows*/); if (focusChanged) { imMayMove = false; } } if (imMayMove) { moveInputMethodWindowsIfNeededLocked(false); } assignLayersLocked(displayContent.getWindowList()); // Don't do layout here, the window must call // relayout to be displayed, so we'll do it there. if (focusChanged) { mInputMonitor.setInputFocusLw(mCurrentFocus, false /*updateInputWindows*/); } mInputMonitor.updateInputWindowsLw(false /*force*/); if (localLOGV || DEBUG_ADD_REMOVE) Slog.v(TAG, "addWindow: New client " + client.asBinder() + ": window=" + win + " Callers=" + Debug.getCallers(5)); if (win.isVisibleOrAdding() && updateOrientationFromAppTokensLocked(false)) { reportNewConfig = true; } } if (reportNewConfig) { sendNewConfiguration(); } Binder.restoreCallingIdentity(origId); return res; }而WindowManagerService的操作是很复杂的：这里先不说，详细请看：
http://blog.csdn.net/luoshengyang/article/details/8462738
2.Window的删除过程
和添加过程相似，首先通过WindowManagerImpl
@Override public void removeView(View view) { mGlobal.removeView(view, false); }然后调用WindowManagerGlobal来实现。public void removeView(View view, boolean immediate) { if (view == null) { throw new IllegalArgumentException("view must not be null"); } synchronized (mLock) { int index = findViewLocked(view, true); View curView = mRoots.get(index).getView(); removeViewLocked(index, immediate); if (curView == view) { return; } throw new IllegalStateException("Calling with view " + view + " but the ViewAncestor is attached to " + curView); } }首先通过findViewLocked找到待删除view的索引，然后通过removeViewLocked来进一步删除private void removeViewLocked(int index, boolean immediate) { ViewRootImpl root = mRoots.get(index); View view = root.getView(); if (view != null) { InputMethodManager imm = InputMethodManager.getInstance(); if (imm != null) { imm.windowDismissed(mViews.get(index).getWindowToken()); } } boolean deferred = root.die(immediate); if (view != null) { view.assignParent(null); if (deferred) { mDyingViews.add(view); } } }然后通过ViewRootImpl的die方法删除，其实在这个里删除有两个方法removeView和removeViewImmediate。他们分别表示异步删除和同步删除。在异步的情况下，die方法只是发送了一个请求删除的消息，这个时候view并没有完成删除，会将其添加到mDyingViews中，mDyingViews中存放的是待删除的view列表。boolean die(boolean immediate) { // Make sure we do execute immediately if we are in the middle of a traversal or the damage // done by dispatchDetachedFromWindow will cause havoc on return. if (immediate && !mIsInTraversal) { doDie(); return false; } if (!mIsDrawing) { destroyHardwareRenderer(); } else { Log.e(TAG, "Attempting to destroy the window while drawing!\n" + " window=" + this + ", title=" + mWindowAttributes.getTitle()); } mHandler.sendEmptyMessage(MSG_DIE); return true; }在doDie方法中主要是通过dispatchDetachedFromWindow方法完成的具体删除动作。void doDie() { checkThread(); if (LOCAL_LOGV) Log.v(TAG, "DIE in " + this + " of " + mSurface); synchronized (this) { if (mRemoved) { return; } mRemoved = true; if (mAdded) { dispatchDetachedFromWindow(); } if (mAdded && !mFirst) { destroyHardwareRenderer(); if (mView != null) { int viewVisibility = mView.getVisibility(); boolean viewVisibilityChanged = mViewVisibility != viewVisibility; if (mWindowAttributesChanged || viewVisibilityChanged) { // If layout params have been changed, first give them // to the window manager to make sure it has the correct // animation info. try { if ((relayoutWindow(mWindowAttributes, viewVisibility, false) & WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) { mWindowSession.finishDrawing(mWindow); } } catch (RemoteException e) { } } mSurface.release(); } } mAdded = false; } WindowManagerGlobal.getInstance().doRemoveView(this); }1.垃圾回收相关的工作，比如清除数据和消息、移除回调2.通过Session的remove方法删除Window，同样，最终会调用WindowManagerService的removeWindow方法
3.调用view的dispatchDetachedFromWindow方法，内部又会调用view的回调，在view从window中移除时，做一些回收资源的操作，终止动画，停止线程等
4.调用WindowManagerGlobal的doRemoveView方法刷新数据，包括mRoots、mParams和mDyingViews，也就是把当前view的数据从这三个集合中删除掉
四、activity的window添加过程
我们是否还记得activity的启动，
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) { attachBaseContext(context); mFragments.attachHost(null /*parent*/); mWindow = new PhoneWindow(this); 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); }在Activity的attach方法中，new出来一个PhoneWindow，activity实现了Window的Callback接口，当window接收到外界的状态改变时就会回调activity的方法了。Window已经创建了，那么activity视图是如何附加到Window上面的呢？我们从setContentView方法可以找到答案。
@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); } mContentParent.requestApplyInsets(); final Callback cb = getCallback(); if (cb != null && !isDestroyed()) { cb.onContentChanged(); } }mContentParent是一个DecorView类型，是一个FrameLayout，它的内容包括标题栏和内部栏。主题不一样可能会发生变化。这里首先判断如果没有DecorView那么就通过installDecor()方法新建一个。然后通过mLayoutInflater.inflate(layoutResID, mContentParent);将view添加到DecorView中。
最后因为activity已经实现了CallBack，调用onContentChange方法通知activity已经添加成功了。
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