在高通安卓平台上写一段U盘自动挂载的代码

以下是一个在高通安卓平台上实现 U 盘自动挂载的代码示例：

public class UsbReceiver extends BroadcastReceiver {

    private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
    private static final String TAG = UsbReceiver.class.getSimpleName();

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
            Log.d(TAG, "USB device attached");
            UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
            if (device != null) {
                // Check if the device has permission to access
                UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
                PendingIntent permissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);
                usbManager.requestPermission(device, permissionIntent);
            }
        } else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
            Log.d(TAG, "USB device detached");
        } else if (ACTION_USB_PERMISSION.equals(action)) {
            synchronized (this) {
                UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                    if (device != null) {
                        // Check if the device is a mass storage device
                        if (device.getInterfaceCount() > 0) {
                            UsbInterface usbInterface = device.getInterface(0);
                            if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_MASS_STORAGE) {
                                // Get the storage device
                                UsbDeviceConnection connection = usbManager.openDevice(device);
                                if (connection != null) {
                                    UsbMassStorageDevice massStorageDevice = UsbMassStorageDevice.getMassStorageDevice(context, device);
                                    if (massStorageDevice != null) {
                                        massStorageDevice.init();
                                        // Get the first partition
                                        UsbFile root = massStorageDevice.getPartition(0).getFileSystem().getRootDirectory();
                                        // Do something with the files in the root directory
                                        Log.d(TAG, "U disk root files: " + Arrays.toString(root.listFiles()));
                                        massStorageDevice.close();
                                    }
                                    connection.close();
                                }
                            }
                        }
                    }
                } else {
                    Log.d(TAG, "Permission denied for device " + device);
                }
            }
        }
    }
}

在这个示例中，我们创建了一个 `UsbReceiver` 类，继承自 `BroadcastReceiver`，用于接收 USB 设备的连接和断开广播。在 `onReceive` 方法中，我们判断广播类型，如果是 `ACTION_USB_DEVICE_ATTACHED`，则获取连接的设备，并请求访问权限。如果是 `ACTION_USB_DEVICE_DETACHED`，则表示设备已断开连接。如果是 `ACTION_USB_PERMISSION`，则表示访问权限已被授予，我们可以使用 `UsbMassStorageDevice` 类访问 U 盘的文件系统，获取 U 盘中的文件列表。

注意，为了使用 `UsbMassStorageDevice` 类，我们需要导入 `usb-mass-storage-lib` 库，可以在项目的 `build.gradle` 文件中添加以下依赖：

implementation 'com.github.mjdev:libaums:0.8.6'