我来分析应用进程的 WindowManager 如何调用到 WindowManagerService.addWindow() 的完整调用链，并绘制时序图。

应用进程 WindowManager 到 WindowManagerService.addWindow() 调用链分析

核心调用流程

sequenceDiagram
    participant App as 应用进程
    participant WMI as WindowManagerImpl
    participant WMG as WindowManagerGlobal
    participant VRI as ViewRootImpl
    participant Session as Session
    participant WMS as WindowManagerService
    
    App->>WMI: 1. addView(view, params)
    Note over WMI: applyTokens(params)
设置window token等
    WMI->>WMG: 2. addView(view, params, display, parentWindow, userId)
    
    WMG->>WMG: 3. 参数验证和准备
    Note over WMG: 检查view不为null
检查params类型
设置硬件加速标志
    
    WMG->>VRI: 4. new ViewRootImpl(context, display)
    Note over VRI: 创建ViewRootImpl实例
    
    WMG->>WMG: 5. 添加到全局数组
    Note over WMG: mViews.add(view)
mRoots.add(root)
mParams.add(wparams)
    
    WMG->>VRI: 6. root.setView(view, wparams, panelParentView, userId)
    
    VRI->>VRI: 7. setView内部处理
    Note over VRI: 设置mView, mAttrs
requestLayout()
创建InputChannel
    
    VRI->>Session: 8. mWindowSession.addToDisplayAsUser(...)
    Note over Session: 通过IWindowSession接口调用
    
    Session->>WMS: 9. mService.addWindow(this, window, attrs, ...)
    Note over WMS: 最终到达目标方法
    
    WMS->>WMS: 10. addWindow内部逻辑
    Note over WMS: 权限检查
创建WindowState
添加到WindowManager

详细代码调用链

1. 应用调用 WindowManagerImpl.addView()

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// WindowManagerImpl.java
@Override
public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
    applyTokens(params);
    mGlobal.addView(view, params, mContext.getDisplayNoVerify(), mParentWindow,
            mContext.getUserId());
}

2. WindowManagerGlobal.addView() 处理

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// WindowManagerGlobal.java
public void addView(View view, ViewGroup.LayoutParams params,
        Display display, Window parentWindow, int userId) {
    // 参数验证...
    final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
    
    // 创建ViewRootImpl
    root = new ViewRootImpl(view.getContext(), display);
    
    // 添加到全局数组
    mViews.add(view);
    mRoots.add(root);
    mParams.add(wparams);
    
    // 调用ViewRootImpl.setView()
    root.setView(view, wparams, panelParentView, userId);
}

3. ViewRootImpl.setView() 核心处理

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// ViewRootImpl.java
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView, int userId) {
    synchronized (this) {
        if (mView == null) {
            mView = view;
            mWindowAttributes.copyFrom(attrs);
            
            // 请求首次布局
            requestLayout();
            
            // 创建InputChannel
            InputChannel inputChannel = null;
            if ((mWindowAttributes.inputFeatures & INPUT_FEATURE_NO_INPUT_CHANNEL) == 0) {
                inputChannel = new InputChannel();
            }
            
            // 调用Session.addToDisplayAsUser()
            res = mWindowSession.addToDisplayAsUser(mWindow, mWindowAttributes,
                    getHostVisibility(), mDisplay.getDisplayId(), userId,
                    mInsetsController.getRequestedVisibleTypes(), inputChannel, ...);
        }
    }
}

4. Session.addToDisplayAsUser() 代理

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// Session.java
@Override
public int addToDisplayAsUser(IWindow window, WindowManager.LayoutParams attrs,
        int viewVisibility, int displayId, int userId, @InsetsType int requestedVisibleTypes,
        InputChannel outInputChannel, ...) {
    return mService.addWindow(this, window, attrs, viewVisibility, displayId, userId,
            requestedVisibleTypes, outInputChannel, ...);
}

5. WindowManagerService.addWindow() 最终实现

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// WindowManagerService.java
public int addWindow(Session session, IWindow client, LayoutParams attrs, int viewVisibility,
        int displayId, int requestUserId, @InsetsType int requestedVisibleTypes, ...) {
    
    // 权限检查
    int res = mPolicy.checkAddPermission(attrs.type, isRoundedCornerOverlay, attrs.packageName, appOp);
    
    // 创建WindowState
    final WindowState win = new WindowState(this, session, client, token, parentWindow,
            appOp[0], attrs, viewVisibility, session.mUid, userId,
            session.mCanAddInternalSystemWindow);
    
    // 添加到WindowManager
    win.mToken.addWindow(win);
    displayPolicy.addWindowLw(win, attrs);
}

关键组件说明

WindowManagerGlobal：

  • 全局单例，管理所有窗口
  • 维护 mViews、mRoots、mParams 三个数组
  • 负责创建 ViewRootImpl 实例

ViewRootImpl：

  • 每个窗口的根视图容器
  • 负责窗口的布局、绘制、输入事件处理
  • 与 WindowManagerService 通信的桥梁

Session：

  • WindowManagerService 为每个客户端进程创建的唯一会话
  • 封装了客户端与 WMS 之间的通信
  • 记录客户端进程信息（UID、PID等）

WindowState：

  • WindowManagerService 中表示单个窗口的实体
  • 包含窗口的所有状态信息
  • 真正的窗口管理层对象

总结

完整调用链：应用 WindowManagerImpl → WindowManagerGlobal → ViewRootImpl → Session → WindowManagerService.addWindow()