应用在每次 Phone 重启时请求 USB 许可

Question

我正在使用 USB 接收器处理与通过 USB 连接到 Phone 的温度传感器的通信。

到目前为止一切正常，但是如果我重新启动 Phone，应用程序会在重新启动后直接抛出一个 USB-Permission 弹出窗口，即使有Phone 那一刻没有任何 USB 设备连接。

有没有人知道是什么导致了这个奇怪的问题？

[ 编辑： 抱歉，该应用程序未请求 USB 权限，如果 "this device is connected" 但弹出窗口询问我是否要打开该应用程序显然没有连接设备。]

USB 接收器代码如下：

//Initial USB Settings Receiver
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {

    @Override
    public void onReceive(final Context context, final Intent intent) {
        final String action = intent.getAction();

        if (ACTION_USB_PERMISSION.equals(action)) {
            synchronized (this) {
                final UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);

                // is usb permission has been granted, try to open a connection
                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                    if (device != null) {
                        // call method to set up device communication
                        Constants result = mcp2221.open();

                        if (result != Constants.SUCCESS) {
                            //nothing by now
                        } else {
                            openConnectionToMCP2221();
                        }
                    }
                }
            }
        }

        if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
            // close the connection and release all resources
            closeAllResources();
            // leave a bit of time for the COM thread to close
            try {
                Thread.sleep(20);
            }catch(InterruptedException e){e.printStackTrace();}
            mcp2221Comm = null;
            Toast.makeText(getApplicationContext(), "Device detached",
                    Toast.LENGTH_SHORT).show();
        }

        if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
            final UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
            if (device != null) {
                Toast.makeText(getApplicationContext(), "Device attached",
                        Toast.LENGTH_SHORT).show();
                mStopUSBThread=false;

                // only try to connect if an MCP2221 is attached
                if (device.getVendorId() == MCP2221_VID && device.getProductId() == MCP2221_PID) {
                    Constants result = mcp2221.open();

                    switch (result) {
                        case SUCCESS:
                            openConnectionToMCP2221();
                            break;
                        case CONNECTION_FAILED:
                            Toast.makeText(getApplicationContext(), "ERROR: connection failed", Toast.LENGTH_SHORT).show();
                            break;
                        case NO_USB_PERMISSION:
                            Toast.makeText(getApplicationContext(), "ERROR: no USB permission", Toast.LENGTH_SHORT).show();
                            mcp2221.requestUsbPermission(mPermissionIntent);
                            break;
                        default:
                            break;
                    }
                }
            }
        }

    }
};

这是 onCreate() 部分：

//USB Connection
    mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
    final IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);

    filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
    filter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
    registerReceiver(mUsbReceiver, filter);
    //Checking if theres a Device already connected
    .......

Answer 1

知道了！这是一个

<intent-filter>
            <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"/>
</intent-filter>

在 <activity> 下的 AndroidManifest.xml 中声明。

我不完全明白，为什么会导致这个 Bug，但是删除它可以在解决问题的同时保留我的应用程序的功能。

只有 'negative' 方面可能是，如果传感器连接到 phone，应用程序现在不会要求打开。

应用在每次 Phone 重启时请求 USB 许可

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