在Android 6.0中读取OTG_USB U盘中的数据

 private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (ACTION_USB_PERMISSION.equals(action)) {
                UsbDevice device_ = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                    if (device_ != null) {
                        try {
                            if (device != null) {
                                device.init();
                                FileSystem fs = device.getPartitions().get(0).getFileSystem();
//                                Log.d("TAG", "Capacity: " + fs.getCapacity());
//                                Log.d("TAG", "Occupied Space: " + fs.getOccupiedSpace());
//                                Log.d("TAG", "Free Space: " + fs.getFreeSpace());
                                //新增OTG目录  OTG_USB_TAG标示为OTG目录
                                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                                    list.add(0,new EntryItem(device_.getManufacturerName(), OTG_USB_TAG, ContextCompat.getDrawable(mainActivity, R.drawable.ic_sd_storage_white_56dp)));
                                } else {
                                    list.add(0,new EntryItem(OTG_USB_TAG, OTG_USB_TAG, ContextCompat.getDrawable(mainActivity, R.drawable.ic_sd_storage_white_56dp)));
                                }

                                adapter = new DrawerAdapter(con, list, MainActivity.this, Sp);
                                mDrawerList.setAdapter(adapter);
                                //root.getName()
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }

            } else if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {

                usbDevice = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);

                UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);

                UsbMassStorageDevice[] devices = UsbMassStorageDevice.getMassStorageDevices(MainActivity.this);

                if (devices.length == 0) {
                    return;
                }

                device = devices[0];

              //  Toast.makeText(MainActivity.this, "2:" + usbManager.hasPermission(usbDevice), Toast.LENGTH_LONG).show();

                if (usbDevice != null && usbManager.hasPermission(usbDevice)) {

                    //Toast.makeText(MainActivity.this, "2:received usb device via intent::" + usbDevice, Toast.LENGTH_LONG).show();

                    // Log.d("TAG", "received usb device via intent");

                } else {
                    PendingIntent permissionIntent = PendingIntent.getBroadcast(MainActivity.this, 0, new Intent(
                            ACTION_USB_PERMISSION), 0);
                    usbManager.requestPermission(device.getUsbDevice(), permissionIntent);
                }
            } else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
                //Toast.makeText(MainActivity.this, "3", Toast.LENGTH_LONG).show();
                refreshDrawer();
            }

        }
    };