USBDevice为什么onReceive（）一直被调用

Question

我正在创建一个活动，该活动在将USBDevice连接到Android设备时会对其进行检测，然后将文件复制到该USBDevice上，然后加载该文件并删除该文件。现在，我有一个BroadcastReceiver，由于某种原因，只要插入USBDevice，onReceive函数就会被连续调用，即使在移除设备后仍会继续，但是没有选中我的Checkbox。我只是不断看到onReceive函数中的println行。谁知道这是为什么吗？

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        globalVars = ((GlobalVars) getApplicationContext());
        strModel = globalVars.getModel();
        strName = globalVars.getName();

        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        setContentView(R.layout.activity_usb_host_test);

        globalVars.ClearResultFile("USBHostTestResultFAIL.txt", this, Context.MODE_WORLD_READABLE);

        IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);

        manager = (UsbManager) getSystemService(Context.USB_SERVICE);
        permissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);

        initViews();
        registerReceiver(usbReceiver, filter);

        Context context = getApplicationContext();

        filter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
        context.registerReceiver(usbReceiver, filter);

    }

    public void initViews()
    {      
        mPort1 = (CheckBox) findViewById(R.id.checkBoxPort1);
        mPort2 = (CheckBox) findViewById(R.id.checkBoxPort2);
        mPort3 = (CheckBox) findViewById(R.id.checkBoxPort3);
        mTextViewMessage = (TextView) findViewById(R.id.textViewMessage);
        mTextViewCopy = (TextView) findViewById(R.id.TextViewCopy);
        mTextViewLoad = (TextView) findViewById(R.id.TextViewLoad);
        mTextViewDelete = (TextView) findViewById(R.id.TextViewDelete);
        mFailButton = (Button) findViewById(R.id.buttonFail);
        color_default = Color.BLUE;
        color_testing = Color.YELLOW;
        color_pass = Color.GREEN;
        color_fail = Color.RED;
        mTextViewCopy.setTextColor(color_default);
        mTextViewLoad.setTextColor(color_default);
        mTextViewDelete.setTextColor(color_default);
        mModel = (TextView) findViewById(R.id.textViewModel);
        mModel.setText(strModel);
        AllPassed = true;
        mTextViewMessage.setText(getResources().getString(R.string.str_usb_host_test_6000_message));
        CurrentPort = 0;
    }

        private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {

            public void onReceive(Context context, Intent intent) {
                String action = intent.getAction();
                System.out.println(action);
                        UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                        manager.requestPermission(device, permissionIntent);
                        if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                            if (device != null) {
                                if (PortList[CurrentPort] != 1) {
                                    if (CurrentPort < 4) {
                                        switch (CurrentPort) {
                                            case 1:
                                                if (!CopyFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                if (!LoadFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                if (!DeleteFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                PassCurrentPort(CurrentPort);
                                                CheckComplete();
                                                break;
                                            case 2:
                                                if (!CopyFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                if (!LoadFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                if (!DeleteFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                PassCurrentPort(CurrentPort);

                                                break;
                                            case 3:
                                                if (!CopyFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                if (!LoadFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);
                                                if (!DeleteFile(FileToCopy, CurrentPort))
                                                    FailCurrentPort(CurrentPort);


                                                break;
                                            default:
                                                break;

                                        }
                                        if (CurrentPort < TotalPorts)
                                            CurrentPort++;
                                    }
                                }
                            }
                        } else {
                            Log.d(TAG, "permission denied for device " + device);
                        }

                }
        };



    public boolean CopyFile(String Filename, int PortNumber)
    {
        AssetManager am = this.getAssets();
        AssetFileDescriptor afd;
        try {
            afd = am.openFd(Filename);

            File file;

            file = new File("/mnt/ext_HSusb" + PortNumber + "/" + java.io.File.separator + Filename);

            if(file.exists())
                mTextViewCopy.setTextColor(color_pass);

            file.createNewFile();
            CopyToSDCard(afd.getFileDescriptor(), file);

        } catch (IOException e) {
            e.printStackTrace();
            mTextViewCopy.setTextColor(color_fail);
            return false;
        }
        mTextViewCopy.setTextColor(color_pass);
        return true;
    }

    public static void CopyToSDCard(FileDescriptor src, File dst) throws IOException 
    {
        FileChannel inChannel = new FileInputStream(src).getChannel();
        FileChannel outChannel = new FileOutputStream(dst).getChannel();
        try {
            inChannel.transferTo(0, inChannel.size(), outChannel);
        } finally 
        {
            if (inChannel != null)
                inChannel.close();
        }
    }

    public boolean LoadFile(String Filename, int PortNumber)
    {
        File file = new File("/mnt/ext_HSusb" + PortNumber + "/" + java.io.File.separator + Filename);

        if (file.exists())
            mTextViewLoad.setTextColor(color_pass);
        else
            mTextViewLoad.setTextColor(color_fail);


        return file.exists();
    }

    public boolean DeleteFile(String Filename, int PortNumber)
    {
        File file = new File("/mnt/ext_HSusb" + PortNumber + "/" + java.io.File.separator + Filename);
        boolean deleted = file.delete();
        if (deleted)
            mTextViewDelete.setTextColor(color_pass);
        else
            mTextViewDelete.setTextColor(color_fail);

        return deleted;
    }


    public void FailCurrentPort(int PortNumber)
    {
        PortList[PortNumber] = 1;
        switch (PortNumber)
        {
        case 1:
            mPort1.setTextColor(color_fail);
            mPort2.setTextColor(color_testing);
            break;
        case 2:
            mPort2.setTextColor(color_fail);
            mPort3.setTextColor(color_testing);
            break;
        case 3:
            mPort3.setTextColor(color_fail);
            break;
        }
        AllPassed = false;
        mTextViewCopy.setTextColor(color_default);
        mTextViewLoad.setTextColor(color_default);
        mTextViewDelete.setTextColor(color_default);
        CurrentPort++;
        step = 0;
    }