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如果有人可以提供帮助，那就太好了。我查看了其他地方提供的解决方案，但它们似乎无法解决我的问题。

我正在使用 DeviceAdminReceiver 并在按下按钮时测试锁定设备。它确实可以工作，但是我第一次运行应用程序时会遇到 Activity 崩溃。（这种崩溃只会在第一次运行时发生）。

java.lang.RuntimeException: Unable to instantiate receiver c: java.lang.InstantiationException: can't instantiate class com.example.deviceadmin.MainActivity$myAdmin; no empty constructor

我已经尝试了很多方法来解决这个问题：

1) 将构造函数添加到 DeviceAdminReceiver 的子类
2) 在构造函数内部调用 Super。

这是我看到的建议的解决方案，但它不起作用。

这是我的应用程序的简化代码：

公共类 MainActivity 扩展 Activity {

protected static final int REQUEST_ENABLE = 0;
private static final String LOG = "adminClient";
private DevicePolicyManager mDPM;
private ComponentName mAdminName;

@Override
protected void onCreate(Bundle savedInstanceState) {
    Log.d(LOG, "onCreate");
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mDPM = (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);
    mAdminName = new ComponentName(this, myAdmin.class);
    Log.d(LOG, "mAdminName = " + mAdminName.toString());

    Button deviceLock = (Button) findViewById(R.id.button1);

    deviceLock.setOnClickListener(new OnClickListener() {


        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Log.d(LOG, "LockPhone clicked");
            lockPhone();
        }

    });

}





protected void lockPhone() {
       if (!mDPM.isAdminActive(mAdminName)) {

            Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
            intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,
            mAdminName);
            intent.putExtra("force-locked", DeviceAdminInfo.USES_POLICY_FORCE_LOCK);        
            startActivityForResult(intent, REQUEST_ENABLE);
            } 
           else {   
            Log.d(LOG, "lockDown phone");
            mDPM.lockNow();
            }
}


class myAdmin extends DeviceAdminReceiver {

    public myAdmin(){
        super();

    }


}

}

日志

08-16 14:46:06.383: E/AndroidRuntime(17963): FATAL EXCEPTION: main
08-16 14:46:06.383: E/AndroidRuntime(17963): java.lang.RuntimeException: Unable to instantiate receiver com.example.deviceadmin.MainActivity$myAdmin: java.lang.InstantiationException: can't instantiate class com.example.deviceadmin.MainActivity$myAdmin; no empty constructor
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.app.ActivityThread.handleReceiver(ActivityThread.java:2356)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.app.ActivityThread.access$1500(ActivityThread.java:140)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1309)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.os.Looper.loop(Looper.java:137)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.app.ActivityThread.main(ActivityThread.java:5047)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at java.lang.reflect.Method.invokeNative(Native Method)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at java.lang.reflect.Method.invoke(Method.java:525)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:588)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at dalvik.system.NativeStart.main(Native Method)
08-16 14:46:06.383: E/AndroidRuntime(17963): Caused by: java.lang.InstantiationException: can't instantiate class com.example.deviceadmin.MainActivity$myAdmin; no empty constructor
08-16 14:46:06.383: E/AndroidRuntime(17963):    at java.lang.Class.newInstanceImpl(Native Method)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at java.lang.Class.newInstance(Class.java:1130)
08-16 14:46:06.383: E/AndroidRuntime(17963):    at android.app.ActivityThread.handleReceiver(ActivityThread.java:2351)
08-16 14:46:06.383: E/AndroidRuntime(17963):    ... 10 more
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1 回答 1

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myAdmin需要是一个public static内部类，或者是一个单独的publicJava 类。你有一个非public，非static内部类，它不起作用。

于 2013-08-16T14:14:14.120 回答