Intent Filter not calling onceceive for USB_ACCESSORY_ATTACHED

Question

我已經在MyDialogFragment的構造函數中聲明瞭USB_ACCESSORY_ATTACHED的意圖過濾器，並在片段的onResume和方法中註冊/取消註冊。 MyReceiver在內部類中延伸BroadcastReceiver以接收USB_ACCESSORY_ATTACHED意圖。請參見下面的代碼：

public class MyDialogFragment extends DialogFragment { 

    private Context context; 
    private IntentFilter usbIntentFilter; 
    private MyReceiver myReceiver; 

    MyDialogFragment(Context context) { 
     usbIntentFilter = new IntentFilter(UsbManager.ACTION_USB_ACCESSORY_ATTACHED); 
     myReceiver = new myReceiver(); 
     this.context = context; 
    } 


    @Override 
    public void onResume() { 
      super.onResume(); 

      // Register broadcast receiver 
     context.registerReceiver(myReceiver, usbIntentFilter); 
    } 

    @Override 
    public void onPause() { 
      super.onPause(); 

      // Unregister broadcast receiver 
      context.unregisterReceiver(myReceiver); 
    } 

    class MyReceiver extends BroadcastReceiver { 

     @Override 
     public void onReceive(Context context, Intent intent) { 

      Log.d("MyApp","Called USB receiver"); 

     } 
    } 
} 

然而，當我連接USB配件的MyReceiver從來沒有onReceive方法被調用。此外，當我改變的意圖，

usbIntentFilter = new IntentFilter(UsbManager.ACTION_USB_ACCESSORY_DETACHED); 

的MyReceiver的onReceive方法不會被調用。所以我的問題是：爲什麼當我拆下配件時它工作，但是當我連接配件時不工作？

Answer 1

所以看來USB_ACESSORY_ATTACHED意圖實際上從未得到過的活動，看到這麼一個問題：

Android 3.1 USB-Host - BroadcastReceiver does not receive USB_DEVICE_ATTACHED

你必須與onResume方法由USB_ACCESSORY_ATTACHED間接調用工作。我不得不說，這在Android文檔中並不清楚，我懷疑它的實現。