android - 为什么在 android setBacklightBrightness(int) 中不起作用

Question

我正在尝试通过我的小部件更改亮度用反射(reflect)的方法但是此代码在 setBacklightBrightness.invoke(power, new Object[]{Brightness}) 时刻失败；并写入调用错误。请帮忙!

public static void LoadIPowerClass(Context context)
{   
    try{
    //Load classes and objects

    Object power;
    Context fContext = context;
    Class <?> ServiceManager = Class.forName("android.os.ServiceManager");
    Class <?> Stub = Class.forName("android.os.IPowerManager$Stub");


    Method getService = ServiceManager.getMethod("getService", new Class[] {String.class});
    //Method asInterface = GetStub.getMethod("asInterface", new Class[] {IBinder.class});//of this class?
    Method asInterface = Stub.getMethod("asInterface", new Class[] {IBinder.class});    //of this class?
    IBinder iBinder = (IBinder) getService.invoke(null, new Object[] {Context.POWER_SERVICE});//
    power = asInterface.invoke(null,iBinder);//or call constructor Stub?//

    Method setBacklightBrightness = power.getClass().getMethod("setBacklightBrightness", new Class[]{int.class}); 

    int Brightness = 5;

    setBacklightBrightness.invoke(power, new Object[]{Brightness});//HERE Failen

    Log.i(TAG, "Load internal IPower classes Ok");               
    }catch(InvocationTargetException e){                     //HERE catch!!!!

....

Answer 1

非常感谢您的代码，它工作得很好!

关于您的异常，您可能错过了 DEVICE_POWER在您的应用程序中获得许可。为了获得此权限，您必须使用 root uid。添加android:sharedUserId="android.uid.system"在<manifest>里面使用手机的 OEM key (构造函数使用的私钥，或您的开发平台的私钥)标记和签署您的应用程序。

问候