WMS中Binder案例

android12-release

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1、FWK层中AIDL形式

Android 接口定义语言 (AIDL)、Android 应用层 到 HAL 层

AIDL形式是Android中binder机制的具体实现。按照规范aidl/hidl文件自动生成相应代码文件：
客户端获取proxy：asInterface(android.os.IBinder obj)
服务端实现Stub：class Stub extends android.os.Binder

1.1 服务端实现Stub

WindowManagerService继承IWindowManager.Stub，SystemServer.java中服务初始化添加到ServiceManager中

frameworks/base/services/java/com/android/server/SystemServer.java

frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java

frameworks/base/core/java/android/view/IWindowManager.aidl

1.2 客户端获取proxy

• 应用端获取服务getSystemService(Context.INPUT_SERVICE))，这里通过中getWindowManagerService()方法操作IWindowManager.Stub.asInterface(ServiceManager.getService("window"))
• 直接获取IWindowManager.Stub.asInterface(ServiceManager.getService(Context.WINDOW_SERVICE))

frameworks/base/core/java/android/app/SystemServiceRegistry.java

registerService(Context.WINDOW_SERVICE, WindowManager.class,
        new CachedServiceFetcher<WindowManager>() {
    
    
    @Override
    public WindowManager createService(ContextImpl ctx) {
    
    
        return new WindowManagerImpl(ctx);
    }});

frameworks/base/core/java/android/view/WindowManagerGlobal.java

@UnsupportedAppUsage
public static IWindowManager getWindowManagerService() {
    
    
    synchronized (WindowManagerGlobal.class) {
    
    
        if (sWindowManagerService == null) {
    
    
            sWindowManagerService = IWindowManager.Stub.asInterface(
                    ServiceManager.getService("window"));
            try {
    
    
                if (sWindowManagerService != null) {
    
    
                    ValueAnimator.setDurationScale(
                            sWindowManagerService.getCurrentAnimatorScale());
                    sUseBLASTAdapter = sWindowManagerService.useBLAST();
                }
            } catch (RemoteException e) {
    
    
                throw e.rethrowFromSystemServer();
            }
        }
        return sWindowManagerService;
    }
}

2、紧密相关SurfaceFlinger

SurfaceFlinger中Binder案例