這篇博客我們主要分析下,窗口位置排序的一些原理。
一、添加窗口的時候 調整窗口位置
上篇博客我們分析了WMS的addWindow函數,這裏我們就窗口的次序問題繼續分析。
- boolean imMayMove = true;
-
- if (type == TYPE_INPUT_METHOD) {//如果窗口類是輸入法窗口
- win.mGivenInsetsPending = true;
- mInputMethodWindow = win;
- addInputMethodWindowToListLocked(win);//插入輸入法窗口到應用窗口上層
- imMayMove = false;
- } else if (type == TYPE_INPUT_METHOD_DIALOG) {//如果窗口是輸入法對話框
- mInputMethodDialogs.add(win);
- addWindowToListInOrderLocked(win, true);//插入到正常位置
- moveInputMethodDialogsLocked(findDesiredInputMethodWindowIndexLocked(true));//調整對話框位置
- imMayMove = false;
- } else {
- addWindowToListInOrderLocked(win, true);//插入正常位置
- 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;
- }
- }
DisplayContent類的mWindows列表按Z序保存了每個窗口,這段代碼就是在根據窗口類型把窗口加入到DisplayContent合適位置。
addInputMethodWindowToListLocked方法作用就是一個輸入法窗口放子啊需要顯示輸入法窗口的上面。
addWindowToListInOrderLocked將一個窗口插入到窗口堆棧的當前位置。
我們繼續看addWindow函數,
- final WindowStateAnimator winAnimator = win.mWinAnimator;
- winAnimator.mEnterAnimationPending = true;
- winAnimator.mEnteringAnimation = true;
-
- if (displayContent.isDefaultDisplay) {
- mPolicy.getInsetHintLw(win.mAttrs, mRotation, outContentInsets, outStableInsets,//計算窗口大小
- outOutsets);
- } else {
- outContentInsets.setEmpty();
- outStableInsets.setEmpty();
- }
-
- if (mInTouchMode) {
- res |= WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE;//加入支持觸屏的標誌
- }
- if (win.mAppToken == null || !win.mAppToken.clientHidden) {
- res |= WindowManagerGlobal.ADD_FLAG_APP_VISIBLE;//加入應用可用的標誌
- }
-
- mInputMonitor.setUpdateInputWindowsNeededLw();//設置更新輸入法窗口的標誌
-
- boolean focusChanged = false;
- if (win.canReceiveKeys()) {//如果窗口能接受輸入計算是否引起焦點變化
- focusChanged = updateFocusedWindowLocked(UPDATE_FOCUS_WILL_ASSIGN_LAYERS,
- false /*updateInputWindows*/);
- if (focusChanged) {
- imMayMove = false;
- }
- }
-
- if (imMayMove) {
- moveInputMethodWindowsIfNeededLocked(false);//調整輸入法的窗口位置
- }
-
- assignLayersLocked(displayContent.getWindowList());//重新計算z軸的位置
- // 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*/);//更新輸入法窗口的信息
-
- 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;//配置發生變化
- }
- }
-
- if (reportNewConfig) {
- sendNewConfiguration();//發送新的配置
- }
-
- Binder.restoreCallingIdentity(origId);
-
- return res;
- }
如果窗口顯示在缺省的顯示設備,調用mPolicy的getInsetHintLw函數來獲得除了狀態條、導航條所佔區域後的窗口大小。
接下來如果窗口能接受輸入,調用updateFocusedWindowLocked來重新確定系統的焦點位置。如果焦點發生變化,則將imMayMove置爲false。
新加入的窗口的位置在前面調用addWindowToListInOrderLocked的時候位置已經確定了,所以這裏調用assignLayersLocked只是重新計算Z軸的位置。如果調用updateOrientationFromAppTokensLocked函數計算窗口的配置發生變化,調用sendNewConfiguration函數發送配置。
二、確定窗口的mLayer值
顯示設備的水平方向,垂直方向作爲X軸Y軸,我們還可以想象有一個垂直於屏幕的Z軸,Z軸的值越來越靠近屏幕。系統中所有的窗口都按次序排列在Z軸上。窗口對象WindowState的成員變量mLayer表示窗口在Z軸的值,值越小越靠近底層。
WMS作用之一就是管理各個窗口Z軸位置,確保正確顯示。在所有窗口中輸入法和壁紙窗口比較特殊。輸入法窗口出現時,需要顯示在應用窗口的前面。壁紙窗口通常在底層,但是又不是位於所有窗口的底層,而是位於當前Activity窗口的下面。
因此,當系統調整某個應用窗口的位置時,如果需要也會調整輸入法和壁紙窗口,使當前Activity的窗口位於輸入法窗口和壁紙窗口之間。
WindowState的成員變量mLayer的值表示窗口在Z軸的位置,這個值越小,位置越靠下。mLayer是通過計算得到,會經常變化。WindowState的另一個成員變量mBaseLayer的值是固定不變的,只和窗口類型有關。mLayer的值是根據mBaseLayer的值計算而來。
下面我們先來看看mBaseLayer的值如何而來,在WindowState的構造函數中有如下代碼:
- if ((mAttrs.type >= FIRST_SUB_WINDOW &&
- mAttrs.type <= LAST_SUB_WINDOW)) {//如果是子窗口
- // The multiplier here is to reserve space for multiple
- // windows in the same type layer.
- mBaseLayer = mPolicy.windowTypeToLayerLw(//使用依附窗口的類型
- attachedWindow.mAttrs.type) * WindowManagerService.TYPE_LAYER_MULTIPLIER
- + WindowManagerService.TYPE_LAYER_OFFSET;
- mSubLayer = mPolicy.subWindowTypeToLayerLw(a.type);//計算mSubLayer
- ......
- } else {//非子窗口
- // The multiplier here is to reserve space for multiple
- // windows in the same type layer.
- mBaseLayer = mPolicy.windowTypeToLayerLw(a.type)
- * WindowManagerService.TYPE_LAYER_MULTIPLIER
- + WindowManagerService.TYPE_LAYER_OFFSET;
- mSubLayer = 0;
- ......
- }
如果窗口類型是子窗口,則使用它所依附的窗口類型來計算mBaseLayer,否則使用窗口類型來計算mBaseLayer。計算的方法是先調用mPolicy.windowTypeToLayerLw方法將窗口的類型轉化成一個基數,然後再乘以TYPE_LAYER_MULTIPLIER(10000),最後加上TYPE_LAYER_OFFSET(1000),我們先來看看windowTypeToLayerLw函數是如果根據類型返回一個基數的。
- public int windowTypeToLayerLw(int type) {
- if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) {//應用窗口
- return 2;
- }
- switch (type) {
- case TYPE_PRIVATE_PRESENTATION:
- return 2;
- case TYPE_WALLPAPER:
- // wallpaper is at the bottom, though the window manager may move it.
- return 2;
- case TYPE_PHONE:
- return 3;
- case TYPE_SEARCH_BAR:
- case TYPE_VOICE_INTERACTION_STARTING:
- return 4;
- case TYPE_VOICE_INTERACTION:
- // voice interaction layer is almost immediately above apps.
- return 5;
- case TYPE_INPUT_CONSUMER:
- return 6;
- case TYPE_SYSTEM_DIALOG:
- return 7;
- case TYPE_TOAST:
- // toasts and the plugged-in battery thing
- return 8;
- case TYPE_PRIORITY_PHONE:
- // SIM errors and unlock. Not sure if this really should be in a high layer.
- return 9;
- case TYPE_DREAM:
- // used for Dreams (screensavers with TYPE_DREAM windows)
- return 10;
- case TYPE_SYSTEM_ALERT:
- // like the ANR / app crashed dialogs
- return 11;
- case TYPE_INPUT_METHOD:
- // on-screen keyboards and other such input method user interfaces go here.
- return 12;
- case TYPE_INPUT_METHOD_DIALOG:
- // on-screen keyboards and other such input method user interfaces go here.
- return 13;
- case TYPE_KEYGUARD_SCRIM:
- // the safety window that shows behind keyguard while keyguard is starting
- return 14;
- case TYPE_STATUS_BAR_SUB_PANEL:
- return 15;
- case TYPE_STATUS_BAR:
- return 16;
- case TYPE_STATUS_BAR_PANEL:
- return 17;
- case TYPE_KEYGUARD_DIALOG:
- return 18;
- case TYPE_VOLUME_OVERLAY:
- // the on-screen volume indicator and controller shown when the user
- // changes the device volume
- return 19;
- case TYPE_SYSTEM_OVERLAY:
- // the on-screen volume indicator and controller shown when the user
- // changes the device volume
- return 20;
- case TYPE_NAVIGATION_BAR:
- // the navigation bar, if available, shows atop most things
- return 21;
- case TYPE_NAVIGATION_BAR_PANEL:
- // some panels (e.g. search) need to show on top of the navigation bar
- return 22;
- case TYPE_SYSTEM_ERROR:
- // system-level error dialogs
- return 23;
- case TYPE_MAGNIFICATION_OVERLAY:
- // used to highlight the magnified portion of a display
- return 24;
- case TYPE_DISPLAY_OVERLAY:
- // used to simulate secondary display devices
- return 25;
- case TYPE_DRAG:
- // the drag layer: input for drag-and-drop is associated with this window,
- // which sits above all other focusable windows
- return 26;
- case TYPE_ACCESSIBILITY_OVERLAY:
- // overlay put by accessibility services to intercept user interaction
- return 27;
- case TYPE_SECURE_SYSTEM_OVERLAY:
- return 28;
- case TYPE_BOOT_PROGRESS:
- return 29;
- case TYPE_POINTER:
- // the (mouse) pointer layer
- return 30;
- }
- Log.e(TAG, "Unknown window type: " + type);
- return 2;
- }
這個方法很簡單就是根據類型返回一個基數。
WindowState中的成員變量mSubLayer只有在窗口是子窗口的時候纔有作用,它表示在窗口和父窗口之間的相對位置。代碼如下
- public int subWindowTypeToLayerLw(int type) {
- switch (type) {
- case TYPE_APPLICATION_PANEL:
- case TYPE_APPLICATION_ATTACHED_DIALOG:
- return APPLICATION_PANEL_SUBLAYER;//等於1
- case TYPE_APPLICATION_MEDIA:
- return APPLICATION_MEDIA_SUBLAYER;//等於-2
- case TYPE_APPLICATION_MEDIA_OVERLAY:
- return APPLICATION_MEDIA_OVERLAY_SUBLAYER;//等於-1
- case TYPE_APPLICATION_SUB_PANEL:
- return APPLICATION_SUB_PANEL_SUBLAYER;//等於2
- case TYPE_APPLICATION_ABOVE_SUB_PANEL:
- return APPLICATION_ABOVE_SUB_PANEL_SUBLAYER;//等於3
- }
- Log.e(TAG, "Unknown sub-window type: " + type);
- return 0;
- }
理解了mBaseLayer和mSubLayer後,我們再來看看mLayer是如何計算出來的,是通過assignLayersLocked方法:
- private final void assignLayersLocked(WindowList windows) {
- int N = windows.size();
- int curBaseLayer = 0;
- int curLayer = 0;
- int i;
-
- boolean anyLayerChanged = false;
-
- for (i=0; i<N; i++) {
- final WindowState w = windows.get(i);
- final WindowStateAnimator winAnimator = w.mWinAnimator;
- boolean layerChanged = false;
- int oldLayer = w.mLayer;
- if (w.mBaseLayer == curBaseLayer || w.mIsImWindow
- || (i > 0 && w.mIsWallpaper)) {//如果窗口的mBaseLayer和前一個相同、或者是輸入法和壁紙窗口
- curLayer += WINDOW_LAYER_MULTIPLIER;
- w.mLayer = curLayer;
- } else {
- curBaseLayer = curLayer = w.mBaseLayer;
- w.mLayer = curLayer;
- }
- if (w.mLayer != oldLayer) {//層級發生改變
- layerChanged = true;
- anyLayerChanged = true;
- }
- final AppWindowToken wtoken = w.mAppToken;
- oldLayer = winAnimator.mAnimLayer;//後面都是調整mAnimLayerd的值
- if (w.mTargetAppToken != null) {
- winAnimator.mAnimLayer =
- w.mLayer + w.mTargetAppToken.mAppAnimator.animLayerAdjustment;
- } else if (wtoken != null) {
- winAnimator.mAnimLayer =
- w.mLayer + wtoken.mAppAnimator.animLayerAdjustment;
- } else {
- winAnimator.mAnimLayer = w.mLayer;
- }
- if (w.mIsImWindow) {
- winAnimator.mAnimLayer += mInputMethodAnimLayerAdjustment;
- } else if (w.mIsWallpaper) {
- winAnimator.mAnimLayer += mWallpaperAnimLayerAdjustment;
- }
- if (winAnimator.mAnimLayer != oldLayer) {
- layerChanged = true;
- anyLayerChanged = true;
- }
- final TaskStack stack = w.getStack();
- if (layerChanged && stack != null && stack.isDimming(winAnimator)) {
- // Force an animation pass just to update the mDimLayer layer.
- scheduleAnimationLocked();
- }
- }
-
- if (mAccessibilityController != null && anyLayerChanged
- && windows.get(windows.size() - 1).getDisplayId() == Display.DEFAULT_DISPLAY) {
- mAccessibilityController.onWindowLayersChangedLocked();
- }
- }
在調用assignLayersLocked函數之前,WindowList中的窗口其實已經排好序了,前面調用的函數addWindowToListInOrderLocked就是插入窗口到合適的位置,assignLayersLocked函數並不會改變窗口的位置,只是根據窗口的位置計算mLayer的值。
調整方法是從最底層的窗口開始,具有相同的mBaseLayer的值作爲一組,每組窗口的mLayer的值從mBaseLayer的值開始,依次加上WINDOW_LAYER_MULTIPLIER(等於5),這樣做的目的是在同層的窗口中每隔一個窗口就留下4個空位,方便下次插入新窗口。
這個方法還對輸入法和壁紙窗口做了特殊處理。這兩類窗口和它插入位置前面的窗口處於一個層級,而不是根據他們的mBaseLayer值計算。(就是前面說的當輸入法和壁紙出現是在當前Activity的窗口之間的)。
三、插入窗口的位置
在addWindow函數中我們會調用addAppWindowToListLocked來確定窗口的位置,現在我們來看下這個函數。
- private void addWindowToListInOrderLocked(final WindowState win, boolean addToToken) {
- if (win.mAttachedWindow == null) {//非子窗口
- final WindowToken token = win.mToken;
- int tokenWindowsPos = 0;
- if (token.appWindowToken != null) {//應用窗口的頂層窗口
- tokenWindowsPos = addAppWindowToListLocked(win);
- } else {
- addFreeWindowToListLocked(win);//系統窗口
- }
- if (addToToken) {
- if (DEBUG_ADD_REMOVE) Slog.v(TAG, "Adding " + win + " to " + token);
- token.windows.add(tokenWindowsPos, win);
- }
- } else {
- addAttachedWindowToListLocked(win, addToToken);//添加子窗口
- }
-
- if (win.mAppToken != null && addToToken) {
- win.mAppToken.allAppWindows.add(win);
- }
- }
上面這個函數根據窗口的類型,應用頂層窗口,系統窗口,子窗口。
我們現在分別對這三類窗口的處理方法進行解析,先來看插入Activity頂層窗口的addAppWindowToListLocked
1.插入Activity頂層方法的addAppWindowToListLocked方法
addAppWindowToListLocked方法先判斷系統中是否存在和待插入的窗口是否有相同的Token,如果有代表它不是Activity的第一個窗口,因此再判斷這個窗口的類型是不是TYPE_BASE_APPLICATION,如果是這類窗口需要放在所有和它相同Token的窗口下面,否則在判斷這個應用的啓動窗口是否位於最前面(說明正在啓動),如果是放在啓動窗口的下面。如果不是下面兩種情況,則尋找同一應用中位置最高的窗口,然後插在它上面,這表示加入的窗口將覆蓋在前面的窗口之上。
下面是部分代碼,
- private int addAppWindowToListLocked(final WindowState win) {
- final IWindow client = win.mClient;
- final WindowToken token = win.mToken;
- final DisplayContent displayContent = win.getDisplayContent();
- if (displayContent == null) {
- // It doesn't matter this display is going away.
- return 0;
- }
-
- final WindowList windows = win.getWindowList();
- final int N = windows.size();
- WindowList tokenWindowList = getTokenWindowsOnDisplay(token, displayContent);
- int tokenWindowsPos = 0;
- int windowListPos = tokenWindowList.size();
- if (!tokenWindowList.isEmpty()) {//如果有,說明它不是第一個窗口
- // If this application has existing windows, we
- // simply place the new window on top of them... but
- // keep the starting window on top.
- if (win.mAttrs.type == TYPE_BASE_APPLICATION) {//放在和它相同Token的窗口下面
- // Base windows go behind everything else.
- WindowState lowestWindow = tokenWindowList.get(0);//第一個0,代表最底層的window
- placeWindowBefore(lowestWindow, win);//放在這個window前面
- tokenWindowsPos = indexOfWinInWindowList(lowestWindow, token.windows);
- } else {
- AppWindowToken atoken = win.mAppToken;
- WindowState lastWindow = tokenWindowList.get(windowListPos - 1);
- if (atoken != null && lastWindow == atoken.startingWindow) {
- placeWindowBefore(lastWindow, win);
- tokenWindowsPos = indexOfWinInWindowList(lastWindow, token.windows);
- } else {
- int newIdx = findIdxBasedOnAppTokens(win);//尋找同一token位置最前面的window
- //there is a window above this one associated with the same
- //apptoken note that the window could be a floating window
- //that was created later or a window at the top of the list of
- //windows associated with this token.
- windows.add(newIdx + 1, win);//插在它前面
- if (newIdx < 0) {
- // No window from token found on win's display.
- tokenWindowsPos = 0;
- } else {
- tokenWindowsPos = indexOfWinInWindowList(
- windows.get(newIdx), token.windows) + 1;
- }
- mWindowsChanged = true;
- }
- }
- return tokenWindowsPos;
- }
我們再來看幾個函數
placeWindowBefore函數就是插入到windows這個位置前
- private void placeWindowBefore(WindowState pos, WindowState window) {
- final WindowList windows = pos.getWindowList();
- int i = windows.indexOf(pos);
- if (i < 0) {
- Slog.w(TAG, "placeWindowBefore: Unable to find " + pos + " in " + windows);
- i = 0;
- }
- windows.add(i, window);
- mWindowsChanged = true;
- }
findIdxBasedOnAppTokens函數就是尋找相同token的最前面的window,所以要注意遍歷循環的時候是從window的size最大的時候反過來遍歷的。
- private int findIdxBasedOnAppTokens(WindowState win) {
- WindowList windows = win.getWindowList();
- for(int j = windows.size() - 1; j >= 0; j--) {
- WindowState wentry = windows.get(j);
- if(wentry.mAppToken == win.mAppToken) {
- return j;
- }
- }
- return -1;
- }
繼續看這個函數,如果系統中不存在和窗口具有相同token的窗口(說明Activity剛啓動,第一個窗口還沒有創建完成),這時就會遍歷系統所有的task以及task中包含的AppWindowToken,找到窗口的位置,再在task中排在本窗口前面的窗口中,找出離自己最近的,並且APPWindowToken的窗口列表不爲NULL的窗口,插入到它的最後一個子窗口後面。如果前面的窗口的列表也都爲NULL,則尋找排在本窗口後面的第一個包含有窗口對象的APPWindowToken,把本窗口插在前面。
- WindowState pos = null;
-
- final ArrayList<Task> tasks = displayContent.getTasks();
- int taskNdx;
- int tokenNdx = -1;
- for (taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) {
- AppTokenList tokens = tasks.get(taskNdx).mAppTokens;
- for (tokenNdx = tokens.size() - 1; tokenNdx >= 0; --tokenNdx) {
- final AppWindowToken t = tokens.get(tokenNdx);
- if (t == token) {
- --tokenNdx;
- if (tokenNdx < 0) {
- --taskNdx;
- if (taskNdx >= 0) {
- tokenNdx = tasks.get(taskNdx).mAppTokens.size() - 1;
- }
- }
- break;
- }
-
- // We haven't reached the token yet; if this token
- // is not going to the bottom and has windows on this display, we can
- // use it as an anchor for when we do reach the token.
- tokenWindowList = getTokenWindowsOnDisplay(t, displayContent);
- if (!t.sendingToBottom && tokenWindowList.size() > 0) {
- pos = tokenWindowList.get(0);
- }
- }
- if (tokenNdx >= 0) {
- // early exit
- break;
- }
- }
-
- // We now know the index into the apps. If we found
- // an app window above, that gives us the position; else
- // we need to look some more.
- if (pos != null) {
- // Move behind any windows attached to this one.
- WindowToken atoken = mTokenMap.get(pos.mClient.asBinder());
- if (atoken != null) {
- tokenWindowList =
- getTokenWindowsOnDisplay(atoken, displayContent);
- final int NC = tokenWindowList.size();
- if (NC > 0) {
- WindowState bottom = tokenWindowList.get(0);
- if (bottom.mSubLayer < 0) {
- pos = bottom;
- }
- }
- }
- placeWindowBefore(pos, win);
- return tokenWindowsPos;
- }
-
- // Continue looking down until we find the first
- // token that has windows on this display.
- for ( ; taskNdx >= 0; --taskNdx) {
- AppTokenList tokens = tasks.get(taskNdx).mAppTokens;
- for ( ; tokenNdx >= 0; --tokenNdx) {
- final AppWindowToken t = tokens.get(tokenNdx);
- tokenWindowList = getTokenWindowsOnDisplay(t, displayContent);
- final int NW = tokenWindowList.size();
- if (NW > 0) {
- pos = tokenWindowList.get(NW-1);
- break;
- }
- }
- if (tokenNdx >= 0) {
- // found
- break;
- }
- }
-
- if (pos != null) {
- // Move in front of any windows attached to this
- // one.
- WindowToken atoken = mTokenMap.get(pos.mClient.asBinder());
- if (atoken != null) {
- final int NC = atoken.windows.size();
- if (NC > 0) {
- WindowState top = atoken.windows.get(NC-1);
- if (top.mSubLayer >= 0) {
- pos = top;
- }
- }
- }
- placeWindowAfter(pos, win);
- return tokenWindowsPos;
- }
-
- ......
如果前面窗口的APPWindowToken的窗口列表也爲空,則重新遍歷整個窗口,然後根據mBaseLayer的值來確定窗口的位置。
- final int myLayer = win.mBaseLayer;
- int i;
- for (i = N - 1; i >= 0; --i) {
- WindowState w = windows.get(i);
- if (w.mBaseLayer <= myLayer) {
- break;
- }
- }
- if (DEBUG_FOCUS_LIGHT || DEBUG_WINDOW_MOVEMENT || DEBUG_ADD_REMOVE) Slog.v(TAG,
- "Based on layer: Adding window " + win + " at " + (i + 1) + " of " + N);
- windows.add(i + 1, win);
- mWindowsChanged = true;
- return tokenWindowsPos;
2. 插入子窗口的addAttachedWindowToListLocked函數
addAttachedWindowToListLocked方法,如果mSubLayer大於0的子窗口,按mSubLayer的值大小插入到有相同WindowToken的子窗口的合適位置中,如果mSubLayer相同,插入已插入窗口的下層位置,如果mSubLayer小於0,如果還存在mSubLayer小於0,並且大於等於該窗口的mSubLayer的值的子窗口,則插入到該子窗口之下,否則插入到子窗口所依附的窗口下面。
- private void addAttachedWindowToListLocked(final WindowState win, boolean addToToken) {
- final WindowToken token = win.mToken;
- final DisplayContent displayContent = win.getDisplayContent();
- if (displayContent == null) {
- return;
- }
- final WindowState attached = win.mAttachedWindow;
-
- WindowList tokenWindowList = getTokenWindowsOnDisplay(token, displayContent);
-
- // Figure out this window's ordering relative to the window
- // it is attached to.
- final int NA = tokenWindowList.size();
- final int sublayer = win.mSubLayer;
- int largestSublayer = Integer.MIN_VALUE;
- WindowState windowWithLargestSublayer = null;
- int i;
- for (i = 0; i < NA; i++) {
- WindowState w = tokenWindowList.get(i);
- final int wSublayer = w.mSubLayer;
- if (wSublayer >= largestSublayer) {
- largestSublayer = wSublayer;
- windowWithLargestSublayer = w;
- }
- if (sublayer < 0) {
- // For negative sublayers, we go below all windows
- // in the same sublayer.
- if (wSublayer >= sublayer) {
- if (addToToken) {
- if (DEBUG_ADD_REMOVE) Slog.v(TAG, "Adding " + win + " to " + token);
- token.windows.add(i, win);
- }
- placeWindowBefore(wSublayer >= 0 ? attached : w, win);
- break;
- }
- } else {
- // For positive sublayers, we go above all windows
- // in the same sublayer.
- if (wSublayer > sublayer) {
- if (addToToken) {
- if (DEBUG_ADD_REMOVE) Slog.v(TAG, "Adding " + win + " to " + token);
- token.windows.add(i, win);
- }
- placeWindowBefore(w, win);
- break;
- }
- }
- }
- if (i >= NA) {
- if (addToToken) {
- if (DEBUG_ADD_REMOVE) Slog.v(TAG, "Adding " + win + " to " + token);
- token.windows.add(win);
- }
- if (sublayer < 0) {
- placeWindowBefore(attached, win);
- } else {
- placeWindowAfter(largestSublayer >= 0
- ? windowWithLargestSublayer
- : attached,
- win);
- }
- }
- }
3.插入系統窗口的addFreeWindowToListLocked
addFreeWindowToListLocked方法簡單,只是遍歷同一顯示設備上的Windows,比較mBaseLayer值的大小,插入合適位置。
- private void addFreeWindowToListLocked(final WindowState win) {
- final WindowList windows = win.getWindowList();
-
- // Figure out where window should go, based on layer.
- final int myLayer = win.mBaseLayer;
- int i;
- for (i = windows.size() - 1; i >= 0; i--) {
- if (windows.get(i).mBaseLayer <= myLayer) {
- break;
- }
- }
- i++;
- if (DEBUG_FOCUS_LIGHT || DEBUG_WINDOW_MOVEMENT || DEBUG_ADD_REMOVE) Slog.v(TAG,
- "Free window: Adding window " + win + " at " + i + " of " + windows.size());
- windows.add(i, win);
- mWindowsChanged = true;
- }
這篇博客我們分析了window插入到什麼位置,以及mLayer的計算。但是具體裏面有很多變量,stack task windows等,不是很熟悉,下篇博客我們主要分析這。