窗口的顯示在手機上镇眷，是以屏幕左上角為原點咬最，向右為X軸，向下為Y軸欠动，垂直與屏幕表面并指向屏幕外為Z軸永乌。多個窗口依照順序排列在Z軸上顯示，稱為Z order具伍。
WindowState中的序列
在WMS.addWindow的時候翅雏，會為每個窗口創(chuàng)建WindowState用來記錄window 的狀態(tài)。
WindowState(WindowManagerService service, Session s, IWindow c, WindowToken token,
WindowState parentWindow, int appOp, int seq, WindowManager.LayoutParams a,
int viewVisibility, int ownerId, boolean ownerCanAddInternalSystemWindow,
PowerManagerWrapper powerManagerWrapper) {
super(service);
......
//為窗口分配z order
if (mAttrs.type >= FIRST_SUB_WINDOW && mAttrs.type <= LAST_SUB_WINDOW) {
// The multiplier here is to reserve space for multiple
// windows in the same type layer.
mBaseLayer = mPolicy.getWindowLayerLw(parentWindow)
* TYPE_LAYER_MULTIPLIER + TYPE_LAYER_OFFSET;
mSubLayer = mPolicy.getSubWindowLayerFromTypeLw(a.type);
mIsChildWindow = true;
if (DEBUG_ADD_REMOVE) Slog.v(TAG, "Adding " + this + " to " + parentWindow);
//將子窗口windowState添加到父窗口的windowState中
parentWindow.addChild(this, sWindowSubLayerComparator);
mLayoutAttached = mAttrs.type !=
WindowManager.LayoutParams.TYPE_APPLICATION_ATTACHED_DIALOG;
mIsImWindow = parentWindow.mAttrs.type == TYPE_INPUT_METHOD
|| parentWindow.mAttrs.type == TYPE_INPUT_METHOD_DIALOG;
mIsWallpaper = parentWindow.mAttrs.type == TYPE_WALLPAPER;
} else {
// The multiplier here is to reserve space for multiple
// windows in the same type layer.
mBaseLayer = mPolicy.getWindowLayerLw(this)
* TYPE_LAYER_MULTIPLIER + TYPE_LAYER_OFFSET;
mSubLayer = 0;
mIsChildWindow = false;
mLayoutAttached = false;
mIsImWindow = mAttrs.type == TYPE_INPUT_METHOD
|| mAttrs.type == TYPE_INPUT_METHOD_DIALOG;
mIsWallpaper = mAttrs.type == TYPE_WALLPAPER;
}
mIsFloatingLayer = mIsImWindow || mIsWallpaper;
}
其中mBaseLayer與mSubLayer人芽，用于描述窗口顯示次序望几。
- mBaseLayer為主序，用于描述窗口及其所有子窗口在所有窗口的顯示位置萤厅。mBaseLayer值越大橄抹，顯示越靠前
- mSubLayer為子序，描述了一個子窗口在其兄弟窗口中的顯示位置祈坠，mSubLayer值越大害碾，其顯示在同mBaseLayer中的位置越靠前。
主序和子序的關(guān)系赦拘，可以通俗的理解成：主序?qū)c劇院里的樓層慌随，而子序?qū)谠摌菍拥牡趲着拧?br> 對于父窗口，主序取決于其類型躺同，子序則為0阁猜；而對于子窗口，主序與父窗口一致蹋艺，子序取決于子窗口類型剃袍。
DisplayContent中的次序
在DisplayContent構(gòu)造函數(shù)中有按順序依次添加四個子Container：
mBelowAppWindowsContainers、mTaskStackContainers捎谨、
mAboveAppWindowsContainers民效、mImeWindowsContainers。
它們的顯示順序也是依次從里到外顯示涛救，在addWindowToken函數(shù)中根據(jù)windowType添加到對應的Container中畏邢，并且根據(jù)type值進行排序：
/*DisplayContent.java*/
private final NonAppWindowContainers mBelowAppWindowsContainers =
new NonAppWindowContainers("mBelowAppWindowsContainers", mService);
private class NonAppWindowContainers extends DisplayChildWindowContainer<WindowToken> {
/**
* Compares two child window tokens returns -1 if the first is lesser than the second in
* terms of z-order and 1 otherwise.
*/
private final Comparator<WindowToken> mWindowComparator = (token1, token2) ->
// Tokens with higher base layer are z-ordered on-top.
mService.mPolicy.getWindowLayerFromTypeLw(token1.windowType,
token1.mOwnerCanManageAppTokens)
< mService.mPolicy.getWindowLayerFromTypeLw(token2.windowType,
token2.mOwnerCanManageAppTokens) ? -1 : 1;
void addChild(WindowToken token) {
addChild(token, mWindowComparator);
}
......
}
DisplayContent Z order.jpg
其DisplayContent中的顯示層級如圖所示
窗口顯示次序的第二次調(diào)整
在DisplayContent中按照顯示順序?qū)蛹墑澐趾螅呀?jīng)形成基本的Z Order次序检吆，有些特殊情況需要第二次調(diào)整舒萎，如執(zhí)行窗口動畫。
public int addWindow(Session session, IWindow client, int seq,
LayoutParams attrs, int viewVisibility, int displayId, Rect outFrame,
Rect outContentInsets, Rect outStableInsets, Rect outOutsets,
DisplayCutout.ParcelableWrapper outDisplayCutout, InputChannel outInputChannel) {
......
synchronized(mWindowMap) {
......
//完成驗證添加窗口令牌的有效性
//為新窗口創(chuàng)建WindowState,其初始化主序和子序
final WindowState win = new WindowState(this, session, client, token, parentWindow,
appOp[0], seq, attrs, viewVisibility, session.mUid,
session.mCanAddInternalSystemWindow);
......
win.attach();
mWindowMap.put(client.asBinder(), win);
......
win.mToken.addWindow(win); // 注釋1
if (type == TYPE_INPUT_METHOD) {
win.mGivenInsetsPending = true;
setInputMethodWindowLocked(win);
imMayMove = false;
} else if (type == TYPE_INPUT_METHOD_DIALOG) {
//注釋2
displayContent.computeImeTarget(true /* updateImeTarget */);
imMayMove = false;
} else {
if (type == TYPE_WALLPAPER) {
displayContent.mWallpaperController.clearLastWallpaperTimeoutTime();
displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER;
} else if ((attrs.flags&FLAG_SHOW_WALLPAPER) != 0) {
displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER;
} else if (displayContent.mWallpaperController.isBelowWallpaperTarget(win)) {
// 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;
}
}
// If the window is being added to a stack that's currently adjusted for IME,
// make sure to apply the same adjust to this new window.
win.applyAdjustForImeIfNeeded();
if (type == TYPE_DOCK_DIVIDER) {
mRoot.getDisplayContent(displayId).getDockedDividerController().setWindow(win);
}
final WindowStateAnimator winAnimator = win.mWinAnimator;
winAnimator.mEnterAnimationPending = true;
winAnimator.mEnteringAnimation = true;
// Check if we need to prepare a transition for replacing window first.
if (atoken != null && atoken.isVisible()
&& !prepareWindowReplacementTransition(atoken)) {
// If not, check if need to set up a dummy transition during display freeze
// so that the unfreeze wait for the apps to draw. This might be needed if
// the app is relaunching.
prepareNoneTransitionForRelaunching(atoken);
}
final DisplayFrames displayFrames = displayContent.mDisplayFrames;
// TODO: Not sure if onDisplayInfoUpdated() call is needed.
final DisplayInfo displayInfo = displayContent.getDisplayInfo();
displayFrames.onDisplayInfoUpdated(displayInfo,
displayContent.calculateDisplayCutoutForRotation(displayInfo.rotation));
final Rect taskBounds;
if (atoken != null && atoken.getTask() != null) {
taskBounds = mTmpRect;
atoken.getTask().getBounds(mTmpRect);
} else {
taskBounds = null;
}
if (mPolicy.getLayoutHintLw(win.mAttrs, taskBounds, displayFrames, outFrame,
outContentInsets, outStableInsets, outOutsets, outDisplayCutout)) {
res |= WindowManagerGlobal.ADD_FLAG_ALWAYS_CONSUME_NAV_BAR;
}
if (mInTouchMode) {
res |= WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE;
}
if (win.mAppToken == null || !win.mAppToken.isClientHidden()) {
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) {
//注釋2
displayContent.computeImeTarget(true /* updateImeTarget */);
}
// Don't do layout here, the window must call
// relayout to be displayed, so we'll do it there.
win.getParent().assignChildLayers(); //注釋3
if (focusChanged) {
mInputMonitor.setInputFocusLw(mCurrentFocus, false /*updateInputWindows*/);
}
mInputMonitor.updateInputWindowsLw(false /*force*/);
if (localLOGV || DEBUG_ADD_REMOVE) Slog.v(TAG_WM, "addWindow: New client "
+ client.asBinder() + ": window=" + win + " Callers=" + Debug.getCallers(5));
if (win.isVisibleOrAdding() && updateOrientationFromAppTokensLocked(displayId)) {
reportNewConfig = true;
}
}
if (reportNewConfig) {
sendNewConfiguration(displayId);
}
Binder.restoreCallingIdentity(origId);
return res;
}
- 注釋1處：該處通過WindowToken.addWin將根據(jù)mBaseLayer大小排序添加到WindowToken中的mChildren列表中
/* WindowToken.java*/
void addWindow(final WindowState win) {
if (win.isChildWindow()) {
// Child windows are added to their parent windows.
return;
}
if (!mChildren.contains(win)) {
addChild(win, mWindowComparator); //繼承與WindowContainer
mService.mWindowsChanged = true;
}
}
private final Comparator<WindowState> mWindowComparator =
(WindowState newWindow, WindowState existingWindow) -> {
final WindowToken token = WindowToken.this;
return isFirstChildWindowGreaterThanSecond(newWindow, existingWindow) ? 1 : -1;
};
protected boolean isFirstChildWindowGreaterThanSecond(WindowState newWindow,
WindowState existingWindow) {
// New window is considered greater if it has a higher or equal base layer.
return newWindow.mBaseLayer >= existingWindow.mBaseLayer;
}
在WindowToken中的mChildren列表會按照mBaseLayer 由小到大排序蹭沛。
- 注釋2處：displayContent.computeImeTarget(true /* updateImeTarget */)
該函數(shù)主要用于調(diào)整輸入法彈窗的顯示：
WindowState computeImeTarget(boolean updateImeTarget) {
if (mService.mInputMethodWindow == null) {
//如果當前WMS并沒有輸入法
if (updateImeTarget) {
//設置輸入法動畫
setInputMethodTarget(null, mService.mInputMethodTargetWaitingAnim);
}
return null;
}
final WindowState curTarget = mService.mInputMethodTarget;
if (!canUpdateImeTarget()) {
return curTarget;
}
mUpdateImeTarget = updateImeTarget;
WindowState target = getWindow(mComputeImeTargetPredicate);
//輸入法彈窗是啟動窗口類型
if (target != null && target.mAttrs.type == TYPE_APPLICATION_STARTING) {
final AppWindowToken token = target.mAppToken;
if (token != null) {
final WindowState betterTarget = token.getImeTargetBelowWindow(target);//自動找到下面那一層窗口
if (betterTarget != null) {
target = betterTarget;
}
}
}
// Now, a special case -- if the last target's window is in the process of exiting, and the
// new target is home, keep on the last target to avoid flicker. Home is a special case
// since its above other stacks in the ordering list, but layed out below the others.
//當前的輸入法彈窗不為空臂寝，同時當前的進程還存在章鲤，并且下一個要啟動的窗口是Home。則直接返回當前進程的輸入法彈窗
if (curTarget != null && curTarget.isDisplayedLw() && curTarget.isClosing()
&& (target == null || target.isActivityTypeHome())) {
if (DEBUG_INPUT_METHOD) Slog.v(TAG_WM, "New target is home while current target is "
+ "closing, not changing");
return curTarget;
}
//輸入法彈窗為空
if (target == null) {
if (updateImeTarget) {
if (DEBUG_INPUT_METHOD) Slog.w(TAG_WM, "Moving IM target from " + curTarget
+ " to null." + (SHOW_STACK_CRAWLS ? " Callers="
+ Debug.getCallers(4) : ""));
setInputMethodTarget(null, mService.mInputMethodTargetWaitingAnim);
}
return null;
}
//根據(jù)updateImeTarget來確定是否需要輸入法動畫
if (updateImeTarget) {
AppWindowToken token = curTarget == null ? null : curTarget.mAppToken;
if (token != null) {
// Now some fun for dealing with window animations that modify the Z order. We need
// to look at all windows below the current target that are in this app, finding the
// highest visible one in layering.
WindowState highestTarget = null;
if (token.isSelfAnimating()) {
highestTarget = token.getHighestAnimLayerWindow(curTarget);
}
if (highestTarget != null) {
final AppTransition appTransition = mService.mAppTransition;
if (DEBUG_INPUT_METHOD) Slog.v(TAG_WM, appTransition + " " + highestTarget
+ " animating=" + highestTarget.mWinAnimator.isAnimationSet()
+ " layer=" + highestTarget.mWinAnimator.mAnimLayer
+ " new layer=" + target.mWinAnimator.mAnimLayer);
if (appTransition.isTransitionSet()) {
// If we are currently setting up for an animation, hold everything until we
// can find out what will happen.
setInputMethodTarget(highestTarget, true);
return highestTarget;
} else if (highestTarget.mWinAnimator.isAnimationSet() &&
highestTarget.mWinAnimator.mAnimLayer > target.mWinAnimator.mAnimLayer) {
// If the window we are currently targeting is involved with an animation,
// and it is on top of the next target we will be over, then hold off on
// moving until that is done.
setInputMethodTarget(highestTarget, true);
return highestTarget;
}
}
}
if (DEBUG_INPUT_METHOD) Slog.w(TAG_WM, "Moving IM target from " + curTarget + " to "
+ target + (SHOW_STACK_CRAWLS ? " Callers=" + Debug.getCallers(4) : ""));
setInputMethodTarget(target, false);
}
return target;
}
其中setInputMethodTarget主要記錄當前mService.mInputMethodTarget以及mInputMethodTargetWaitingAnim狀態(tài)咆贬，并調(diào)用assignWindowLayers
/** Updates the layer assignment of windows on this display. */
void assignWindowLayers(boolean setLayoutNeeded) {
assignChildLayers(getPendingTransaction());
if (setLayoutNeeded) {
setLayoutNeeded();
}
// We accumlate the layer changes in-to "getPendingTransaction()" but we defer
// the application of this transaction until the animation pass triggers
// prepareSurfaces. This allows us to synchronize Z-ordering changes with
// the hiding and showing of surfaces.
scheduleAnimation();
}
調(diào)用到WindowContainer中函數(shù)
void assignChildLayers(Transaction t) {
int layer = 0;
// We use two passes as a way to promote children which
// need Z-boosting to the end of the list.
for (int j = 0; j < mChildren.size(); ++j) {
final WindowContainer wc = mChildren.get(j);
wc.assignChildLayers(t);
if (!wc.needsZBoost()) {
wc.assignLayer(t, layer++);
}
}
for (int j = 0; j < mChildren.size(); ++j) {
final WindowContainer wc = mChildren.get(j);
if (wc.needsZBoost()) {
wc.assignLayer(t, layer++);
}
}
}
void assignChildLayers() {
assignChildLayers(getPendingTransaction());
scheduleAnimation();
}
assignChildLayers通過 兩個循環(huán)败徊，先將不需要動畫的層級調(diào)整，再調(diào)整需要動畫的層級在不需要動畫的層級之上素征。通過調(diào)整來分離了需要做動畫的層級集嵌，以及普通層級。保證了做動畫的窗口一定在普通窗口之上
