窗口的显示在手机上，是以屏幕左上角为原点，向右为X轴，向下为Y轴，垂直与屏幕表面并指向屏幕外为Z轴。多个窗口依照顺序排列在Z轴上显示，称为Z order。
1:WindowState的次序
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);
.........................
if (mAttrs.type >= FIRST_SUB_WINDOW && mAttrs.type <= LAST_SUB_WINDOW) {//子窗口
// 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);
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;
.........................
}
在WindowState的构造方法中根据窗口类型确定baseLayer和subLayer, 其中mBaseLayer和mSubLayer可以决定该窗口的显示次序
1.1:BaseLayer的确定
BaseLayer用来确定该窗口在所有窗口DisplayContent中的显示次序
default int getWindowLayerFromTypeLw(int type, boolean canAddInternalSystemWindow) {
if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) {
return APPLICATION_LAYER;
}
switch (type) {
case TYPE_WALLPAPER:
// wallpaper is at the bottom, though the window manager may move it.
return 1;
case TYPE_PRESENTATION:
case TYPE_PRIVATE_PRESENTATION:
return APPLICATION_LAYER;
case TYPE_DOCK_DIVIDER:
return APPLICATION_LAYER;
case TYPE_QS_DIALOG:
return APPLICATION_LAYER;
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_SYSTEM_ALERT:
// like the ANR / app crashed dialogs
return canAddInternalSystemWindow ? 11 : 10;
case TYPE_APPLICATION_OVERLAY:
return 12;
case TYPE_DREAM:
// used for Dreams (screensavers with TYPE_DREAM windows)
return 13;
case TYPE_INPUT_METHOD:
// on-screen keyboards and other such input method user interfaces go here.
return 14;
case TYPE_INPUT_METHOD_DIALOG:
// on-screen keyboards and other such input method user interfaces go here.
return 15;
case TYPE_STATUS_BAR:
return 17;
case TYPE_STATUS_BAR_PANEL:
return 18;
case TYPE_STATUS_BAR_SUB_PANEL:
return 19;
case TYPE_KEYGUARD_DIALOG:
return 20;
case TYPE_VOLUME_OVERLAY:
// the on-screen volume indicator and controller shown when the user
// changes the device volume
return 21;
case TYPE_SYSTEM_OVERLAY:
// the on-screen volume indicator and controller shown when the user
// changes the device volume
return canAddInternalSystemWindow ? 22 : 11;
case TYPE_NAVIGATION_BAR:
// the navigation bar, if available, shows atop most things
return 23;
case TYPE_NAVIGATION_BAR_PANEL:
// some panels (e.g. search) need to show on top of the navigation bar
return 24;
case TYPE_SCREENSHOT:
// screenshot selection layer shouldn't go above system error, but it should cover
// navigation bars at the very least.
return 25;
case TYPE_SYSTEM_ERROR:
// system-level error dialogs
return canAddInternalSystemWindow ? 26 : 10;
case TYPE_MAGNIFICATION_OVERLAY:
// used to highlight the magnified portion of a display
return 27;
case TYPE_DISPLAY_OVERLAY:
// used to simulate secondary display devices
return 28;
case TYPE_DRAG:
// the drag layer: input for drag-and-drop is associated with this window,
// which sits above all other focusable windows
return 29;
case TYPE_ACCESSIBILITY_OVERLAY:
// overlay put by accessibility services to intercept user interaction
return 30;
case TYPE_SECURE_SYSTEM_OVERLAY:
return 31;
case TYPE_BOOT_PROGRESS:
return 32;
case TYPE_POINTER:
// the (mouse) pointer layer
return 33;
default:
Slog.e("WindowManager", "Unknown window type: " + type);
return APPLICATION_LAYER;
}
}
1.2:subLayer
subLayer只针对子窗口有效，子窗口有可能在父窗口的下面，也有可能在父窗口的上面
default int getSubWindowLayerFromTypeLw(int type) {
switch (type) {
case TYPE_APPLICATION_PANEL:
case TYPE_APPLICATION_ATTACHED_DIALOG:
return APPLICATION_PANEL_SUBLAYER;
case TYPE_APPLICATION_MEDIA:
return APPLICATION_MEDIA_SUBLAYER;
case TYPE_APPLICATION_MEDIA_OVERLAY:
return APPLICATION_MEDIA_OVERLAY_SUBLAYER;
case TYPE_APPLICATION_SUB_PANEL:
return APPLICATION_SUB_PANEL_SUBLAYER;
case TYPE_APPLICATION_ABOVE_SUB_PANEL:
return APPLICATION_ABOVE_SUB_PANEL_SUBLAYER;
}
Slog.e("WindowManager", "Unknown sub-window type: " + type);
return 0;
}
2:DisplayContent中的次序
DisplayContent默认情况下会创建四种类型的容器来存储当前显示设备上的窗口，这四种容器分别是存储壁纸窗口，应用程序窗口，系统窗口和输入法窗口
/** The containers below are the only child containers the display can have. */
// Contains all window containers that are related to apps (Activities)
private final TaskStackContainers mTaskStackContainers = new TaskStackContainers(mService);
// Contains all non-app window containers that should be displayed above the app containers
// (e.g. Status bar)
private final AboveAppWindowContainers mAboveAppWindowsContainers =
new AboveAppWindowContainers("mAboveAppWindowsContainers", mService);
// Contains all non-app window containers that should be displayed below the app containers
// (e.g. Wallpaper).
private final NonAppWindowContainers mBelowAppWindowsContainers =
new NonAppWindowContainers("mBelowAppWindowsContainers", mService);
// Contains all IME window containers. Note that the z-ordering of the IME windows will depend
// on the IME target. We mainly have this container grouping so we can keep track of all the IME
// window containers together and move them in-sync if/when needed. We use a subclass of
// WindowContainer which is omitted from screen magnification, as the IME is never magnified.
private final NonMagnifiableWindowContainers mImeWindowsContainers =
new NonMagnifiableWindowContainers("mImeWindowsContainers", mService);
在窗口创建的时候被添加到对应的容器中，具体在
if (token.asAppWindowToken() == null) {//如果token不是AppWindowToken
// Add non-app token to container hierarchy on the display. App tokens are added through
// the parent container managing them (e.g. Tasks).
switch (token.windowType) {
case TYPE_WALLPAPER:
mBelowAppWindowsContainers.addChild(token);
break;
case TYPE_INPUT_METHOD:
case TYPE_INPUT_METHOD_DIALOG:
mImeWindowsContainers.addChild(token);
break;
default:
mAboveAppWindowsContainers.addChild(token);
break;
}
}
依据就是窗口类型
显示次序.png
3:窗口次序的二次调整
窗口次序的调整时机应该是有新窗口被添加或是旧的窗口被移除，不管是什么类型的窗口被添加到wms中都是走addWindow方法
final boolean suspended = mPmInternal.isPackageSuspended(win.getOwningPackage(),
UserHandle.getUserId(win.getOwningUid()));
win.setHiddenWhileSuspended(suspended);
final boolean hideSystemAlertWindows = !mHidingNonSystemOverlayWindows.isEmpty();
win.setForceHideNonSystemOverlayWindowIfNeeded(hideSystemAlertWindows);
final AppWindowToken aToken = token.asAppWindowToken();
if (type == TYPE_APPLICATION_STARTING && aToken != null) {
aToken.startingWindow = win;
if (DEBUG_STARTING_WINDOW) Slog.v (TAG_WM, "addWindow: " + aToken
+ " startingWindow=" + win);
}
boolean imMayMove = true;
win.mToken.addWindow(win);
if (type == TYPE_INPUT_METHOD) {
win.mGivenInsetsPending = true;
setInputMethodWindowLocked(win);
imMayMove = false;
} else if (type == TYPE_INPUT_METHOD_DIALOG) {
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;
}
}
这个地方有两个关键点
3.1：win.mToken.addWindow(win);添加到windowContainer中，此时会导致容器中的其他窗口位置会发生变化
WindowToken.java
void addWindow(final WindowState win) {
if (DEBUG_FOCUS) Slog.d(TAG_WM,
"addWindow: win=" + win + " Callers=" + Debug.getCallers(5));
if (win.isChildWindow()) {//如果是子窗口，应该添加到父窗口的容器中
// Child windows are added to their parent windows.
return;
}
if (!mChildren.contains(win)) {//如果WindowContainer中没有添加过
if (DEBUG_ADD_REMOVE) Slog.v(TAG_WM, "Adding " + win + " to " + this);
addChild(win, mWindowComparator);
mService.mWindowsChanged = true;
// TODO: Should we also be setting layout needed here and other places?
}
}
WindowContainer.java
protected void addChild(E child, Comparator<E> comparator) {
if (child.getParent() != null) {
throw new IllegalArgumentException("addChild: container=" + child.getName()
+ " is already a child of container=" + child.getParent().getName()
+ " can't add to container=" + getName());
}
int positionToAdd = -1;
if (comparator != null) {
final int count = mChildren.size();
for (int i = 0; i < count; i++) {
if (comparator.compare(child, mChildren.get(i)) < 0) {
positionToAdd = i;
break;
}
}
}
if (positionToAdd == -1) {
mChildren.add(child);
} else {
mChildren.add(positionToAdd, child);
}
onChildAdded(child);
// Set the parent after we've actually added a child in case a subclass depends on this.
child.setParent(this);
}
//自定义的Comparator
private final Comparator<WindowState> mWindowComparator =
(WindowState newWindow, WindowState existingWindow) -> {
final WindowToken token = WindowToken.this;
if (newWindow.mToken != token) {//如果token不同，那么肯定不是一个容器
throw new IllegalArgumentException("newWindow=" + newWindow
+ " is not a child of token=" + token);
}
if (existingWindow.mToken != token) {//确保容器相同
throw new IllegalArgumentException("existingWindow=" + existingWindow
+ " is not a child of token=" + token);
}
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;//比较baseLayer值
}
上面的逻辑也就是根据窗口的baseLayer值来决定其存储的位置
3.2: DisplayContent.computeImeTarget()计算输入法的目标窗口，输入法窗口永远都是在需要输入法窗口的上面，此时也会导致窗口的位置发生变化
WindowState computeImeTarget(boolean updateImeTarget) {
if (mService.mInputMethodWindow == null) {//如果输入法窗口为null
// There isn't an IME so there shouldn't be a target...That was easy!
if (updateImeTarget) {//更新输入法目标窗口
//将输入法的目标窗口设置为null
setInputMethodTarget(null, mService.mInputMethodTargetWaitingAnim);
}
return null;
}
final WindowState curTarget = mService.mInputMethodTarget;
if (!canUpdateImeTarget()) {//如果不能更新输入法目标窗口
return curTarget;//当前的输入法目标窗口
}
mUpdateImeTarget = updateImeTarget;//更新输入法的全局控制变量
WindowState target = getWindow(mComputeImeTargetPredicate);//找到可以成为输入法目标窗口的窗口
if (target != null && target.mAttrs.type == TYPE_APPLICATION_STARTING) {//如果是应用的启动窗口
final AppWindowToken token = target.mAppToken;
if (token != null) {
final WindowState betterTarget = token.getImeTargetBelowWindow(target);//找到启动窗口下面的一个可作为输入法目标窗口的窗口
if (betterTarget != null) {
target = betterTarget;
}
}
}
if (curTarget != null && curTarget.isDisplayedLw() && curTarget.isClosing()
&& (target == null || target.isActivityTypeHome())) {
return curTarget;
}//如果当前窗口正在退出并且新的目标窗口是桌面，为了避免屏幕闪烁，依然将输入法的目标窗口设为前一个窗口上
if (target == null) {
if (updateImeTarget) {
setInputMethodTarget(null, mService.mInputMethodTargetWaitingAnim);
}
return null;
}
if (updateImeTarget) {
AppWindowToken token = curTarget == null ? null : curTarget.mAppToken;
if (token != null) {
WindowState highestTarget = null;
if (token.isSelfAnimating()) {
highestTarget = token.getHighestAnimLayerWindow(curTarget);//获取容器中anim层级最高的窗口
}
if (highestTarget != null) {
final AppTransition appTransition = mService.mAppTransition;
if (appTransition.isTransitionSet()) {
setInputMethodTarget(highestTarget, true);
return highestTarget;
} else if (highestTarget.mWinAnimator.isAnimationSet() &&
highestTarget.mWinAnimator.mAnimLayer > target.mWinAnimator.mAnimLayer) {
setInputMethodTarget(highestTarget, true);
return highestTarget;
}
}
}
setInputMethodTarget(target, false);
}
return target;
}
private void setInputMethodTarget(WindowState target, boolean targetWaitingAnim) {
if (target == mService.mInputMethodTarget
&& mService.mInputMethodTargetWaitingAnim == targetWaitingAnim) {
return;
}
mService.mInputMethodTarget = target;
mService.mInputMethodTargetWaitingAnim = targetWaitingAnim;
assignWindowLayers(false /* setLayoutNeeded */);//分配计算窗口层级
}
4:WindowContainer::assignWindowLayers
void assignWindowLayers(boolean setLayoutNeeded) {
Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "assignWindowLayers");
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();
Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);
}
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()) {//不需要动画的
wc.assignLayer(t, layer++);
}
}
for (int j = 0; j < mChildren.size(); ++j) {
final WindowContainer wc = mChildren.get(j);
if (wc.needsZBoost()) {//需要动画的
wc.assignLayer(t, layer++);
}
}
}
通过上面的两次for循环上面的layer++保证了需要动画的在不需要动画的上面，通过调整分离了需要做动画和不需要做动画的
5:概述
窗口的层级跟窗口的类型有关，在窗口被添加过程中会根据情况来决定在DisplayContent里面的位置
