Android P WMS简介

Android P WMS简介

Android P WMS初始化过程

Android P WMS addwindow流程

Android P WMS removewindow流程

Android P WMS relayoutWindow流程

Android P WMS windowanimator

Android P WMS Surface

Android P WMS 问题种类和debug分析技巧

Android P WMS View System 简介

Android P WMS简介

WMS是系统的其他服务，无论对于应用开发还是Framework开发都是重点的知识，它的职责有很多，主要有以下几点：

窗口管理
WMS是窗口的管理者，它负责窗口的启动、添加和删除，另外窗口的大小和层级也是由WMS进行管理的。窗口管理的核心成员有DisplayContent、WindowToken和WindowState。

窗口动画
窗口间进行切换时，使用窗口动画可以显得更炫一些，窗口动画由WMS的动画子系统来负责，动画子系统的管理者为WindowAnimator。

输入系统的中转站
通过对窗口的触摸从而产生触摸事件，InputManagerService（IMS）会对触摸事件进行处理，它会寻找一个最合适的窗口来处理触摸反馈信息，WMS是窗口的管理者，因此，WMS“理所应当”的成为了输入系统的中转站。

Surface管理
窗口并不具备有绘制的功能，因此每个窗口都需要有一块Surface来供自己绘制。为每个窗口分配Surface是由WMS来完成的。

WMS的职责可以简单总结为下图。

2.windowState

windowState就是window，每个window都有一个surface来绘画，window本身是没法画的。

Window的类型

Android系统的Window有很多个，大体上来说，Framework定义了三种窗口类型；

系统Window
常见的系统Window有哪些呢？比如在手机电量低的时候，会有一个提示电量低的Window,我们输入文字的时候，会弹出输入法Window,还有搜索条Window,来电显示Window,Toast对应的Window,可以总结出来，系统Window是独立与我们的应用程序的，对于应用程序而言，我们理论上是无法创建系统Window，因为没有权限，这个权限只有系统进程有。

应用程序Window
所谓应用窗口指的就是该窗口对应一个Activity，因此，要创建应用窗口就必须在Activity中完成了。本节后面会分析Activity对应的Window的创建过程。

子Window
所谓的子Window，是说这个Window必须要有一个父窗体，比如PopWindow，Dialog是属于应用程序Window,这个比较特殊。

每一种窗口类型定义了一种对应的type
应用类型的窗口的type范围是１~99

 

应用类型的窗口

子窗口的type范围是1000~1999

 

子窗口

系统的窗口的type范围是2000以上　

 

系统的窗口

系统窗口的type值>子窗口的type值>应用类型窗口的type值，一般来说，根据type值大小关系，可以推出系统窗口在子窗口的上面，子窗口在应用窗口的上面。

 

3.z-order

手机上采用的是层叠式布局，层叠式布局是一个三维的空间，将手机的水平方向作为Ｘ轴，竖直方向作为Ｙ轴，还有一根垂直与屏幕从里朝外方向的虚拟的Z轴，所有窗口 (WindowState) 按照顺序排列在Ｚ轴上，如下图。z轴座标就是z-order，越大证明他的windowState越在前面。

3.1 、 mBaseLayer 主序 确认

@/frameworks/base/services/core/java/com/android/server/wm/WindowState.java
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) {
        ...
    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    //mBaseLayer 主序
                * TYPE_LAYER_MULTIPLIER + TYPE_LAYER_OFFSET;  ////TYPE_LAYER_MULTIPLIER = 10000    TYPE_LAYER_OFFSET = 1000
        mSubLayer = mPolicy.getSubWindowLayerFromTypeLw(a.type);  //mSubLayer 次序
        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;
    }
...
}

mBaseLayer =窗口类型×10000+1000,窗口类型判断如下

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;
    }
}

3.2 、mSubLayer 子序的确认

SubLayer(称为子序)，SubLayer值是用来描述一个窗口是否属于另外一个窗口的子窗口，或者说SubLayer值是用来确定子窗口和父窗口之间的相对位置的。

一个Activity中有三个子窗口WindowState1、WindowState２、WindowState３，WindowState1WindowState２在窗口Ａ的前面，WindowState３在Ａ的后面，这几个兄弟窗口为什么可以这样排序呢，这就是mSubLayer的作用，子序越大，则相对其他兄弟窗口越靠前，反之，越靠后，如果为负数，就处在父窗口的后面，如窗口Ａ中的WindowState3，子序是根据窗口类型调用subWindowTypeToLayerLw确定的，subWindowTypeToLayerLw同样是在Window的构造方法中调用的。

public int subWindowTypeToLayerLw(int type) {
       switch (type) {
       case TYPE_APPLICATION_PANEL:
       case TYPE_APPLICATION_ATTACHED_DIALOG:
           return APPLICATION_PANEL_SUBLAYER;//返回值是1
       case TYPE_APPLICATION_MEDIA:
           return APPLICATION_MEDIA_SUBLAYER;//返回值是-2  
       case TYPE_APPLICATION_MEDIA_OVERLAY:
           return APPLICATION_MEDIA_OVERLAY_SUBLAYER;//返回值是-1  
       case TYPE_APPLICATION_SUB_PANEL:
           return APPLICATION_SUB_PANEL_SUBLAYER;//返回值是2 
       case TYPE_APPLICATION_ABOVE_SUB_PANEL:
           return APPLICATION_ABOVE_SUB_PANEL_SUBLAYER;//返回值是3  
       }
       Log.e(TAG, "Unknown sub-window type: " + type);
       return 0;
   }

 3.3 、窗口Z序的调整

当WindowState创建完成，并且被添加到WMS维持的数组里面后，就需要调用WindowLayersController的assignLayersLocked(windows)，进行Z序的调整。

//参数windows是窗口列表
final void assignLayersLocked(WindowList windows) {
       if (DEBUG_LAYERS) Slog.v(TAG_WM, "Assigning layers based on windows=" + windows,
               new RuntimeException("here").fillInStackTrace());
 
       clear();
       int curBaseLayer = 0;
       int curLayer = 0;
       boolean anyLayerChanged = false;
      //遍历窗口列表，上面通过Z序的计算公式计算出来的Z序值保存在WindowState的变量mBaseLayer
       中，这个循环的意思是，遇到同类型的窗口，后一个窗口在前一个窗口的基础上偏移５。
       for (int i = 0, windowCount = windows.size(); i < windowCount; i++) {
           final WindowState w = windows.get(i);
           boolean layerChanged = false;
 
           int oldLayer = w.mLayer;
           if (w.mBaseLayer == curBaseLayer || w.mIsImWindow || (i > 0 && w.mIsWallpaper)) {
               curLayer += WINDOW_LAYER_MULTIPLIER;
           } else {
               curBaseLayer = curLayer = w.mBaseLayer;
           }
          // 更新该窗口的mAnimLayer，也就是动画显示时，该窗口的层级
           assignAnimLayer(w, curLayer);
 
           // TODO: Preserved old behavior of code here but not sure comparing
           // oldLayer to mAnimLayer and mLayer makes sense...though the
           // worst case would be unintentionalp layer reassignment.
           if (w.mLayer != oldLayer || w.mWinAnimator.mAnimLayer != oldLayer) {
               layerChanged = true;
               anyLayerChanged = true;
           }
 
　　　　　// 将当前应用窗口的最高显示层级记录在mHighestApplicationLayer中
           if (w.mAppToken != null) {
               mHighestApplicationLayer = Math.max(mHighestApplicationLayer,
                       w.mWinAnimator.mAnimLayer);
           }
        　 //  对于分屏等相关的窗口，它们的显示层级需要再次处理
           collectSpecialWindows(w);
 
           if (layerChanged) {
               w.scheduleAnimationIfDimming();
           }
       }
 
　　　　// 调整特殊窗口的层级
       adjustSpecialWindows();
 
       //TODO (multidisplay): Magnification is supported only for the default display.
       if (mService.mAccessibilityController != null && anyLayerChanged
               && windows.get(windows.size() - 1).getDisplayId() == Display.DEFAULT_DISPLAY) {
           mService.mAccessibilityController.onWindowLayersChangedLocked();
       }
 
       if (DEBUG_LAYERS) logDebugLayers(windows);
   }

4.token

Android AMS(六) Activity与WMS的连接过程之AppWindowToken

WmS详解(一)之token到底是什么？基于Android7.0源码

 

参考：

Android解析WindowManagerService（一）WMS的诞生

Android窗口系统第一篇---Window的类型与Z-Order确定

Android AMS(六) Activity与WMS的连接过程之AppWindowToken

WmS详解(一)之token到底是什么？基于Android7.0源码