How to read USB disk through android

<uses-permission android:name=".WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name=".READ_EXTERNAL_STORAGE" />
<uses-permission android:name="" android:required="false" /> 
<uses-feature android:name="" android:required="true" />

 // Listen to otg insertion and unplug IntentFilter usbDeviceStateFilter = new IntentFilter();
 (UsbManager.ACTION_USB_DEVICE_ATTACHED);
 (UsbManager.ACTION_USB_DEVICE_DETACHED);
 (UDiskMountedReceiver, usbDeviceStateFilter);
 //Register and listen to custom broadcast IntentFilter filter = new IntentFilter(Constant.ACTION_USB_PERMISSION);
 (UDiskMountedReceiver, filter);

package ;

/**
  * @Project name: UsbTest
  * @Bank Name:
  * @File Name: ReadUDisk
  * @Creator: 25934
  * @Creation time: 2018-07-24 13:50
  * @Description: TODO
  */

import ;
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import static .ACTION_USB_PERMISSION;

public class ReadUDisk {
 private  mOnUDiskCallBack = null;
 private Context    mContext;
 private UsbMassStorageDevice[] storageDevices;
 private List<UsbFile> usbFiles = new ArrayList<>();
 private final UsbManager mUsbManager;

 public ReadUDisk(Context context) {
  mContext = context;
  mUsbManager = (UsbManager) (Context.USB_SERVICE);
 }

 /**
   * Accept USB drive insertion and unplugging events
   * @param onUDiskCallBack
   */
 public void setOnUDiskCallBack( onUDiskCallBack) {
  if (mOnUDiskCallBack == null) {
   registerReceiver();
   mOnUDiskCallBack = onUDiskCallBack;
  }
 }

 /**
   * Registered broadcast receiver
   */
 public void registerReceiver() {
  // Listen to otg insertion and unplug  IntentFilter usbDeviceStateFilter = new IntentFilter();
  (UsbManager.ACTION_USB_DEVICE_ATTACHED);
  (UsbManager.ACTION_USB_DEVICE_DETACHED);
  (UDiskMountedReceiver, usbDeviceStateFilter);
  //Register and listen to custom broadcast  IntentFilter filter = new IntentFilter(Constant.ACTION_USB_PERMISSION);
  (UDiskMountedReceiver, filter);
  ("ReadUDisk", "registerReceiver: ");
 }

 /**
   * Log out of broadcast receiver
   */
 public void unReisterReceiver() {
  if (UDiskMountedReceiver != null) {
   (UDiskMountedReceiver);
  }
 }

 /**
   * Check the permissions of the USB device
   * @param device
   * @return
   */
 public boolean checkPerssion(UsbMassStorageDevice device) {
  if (mUsbManager==null){
   return false;
  }
  if ((())) {//If you have it, just read directly whether the device has permissions   return true;
  } else {
   return false;
  }
 }


 /**
   * Read the number of current USB devices
   * @return
   */
 public int getDeviceCount() {
  //Get storage device  UsbMassStorageDevice[] storageDevices =(mContext);
  return ;
 }

 /**
   * Get the usb device according to position
   * @param position
   * @return
   */
 public UsbMassStorageDevice getUsbMassDevice(int position) {
  //Get storage device  UsbMassStorageDevice[] storageDevices =(mContext);
  if (position > ) {
   return null;
  } else {
   return storageDevices[position];
  }
 }

 /**
   * Get all storage devices on usb
   * @return
   */
 public UsbMassStorageDevice[] getUsbMassAllDevice() {
  //Get storage device  UsbMassStorageDevice[] storageDevices =(mContext);
  return storageDevices;
 }

 /**
   * Get the path according to the device
   * @param device
   * @return
   */
 public FileSystem readDevice(UsbMassStorageDevice device) {
  try {
   if (!checkPerssion(device)){ //Check whether there is permission    return null;
   }

   ();//Initialization is required before using the device   Partition partition = ().get(0); //Use only the first partition of the device   FileSystem currentFs = ();
   // (); // Capacity size   // (); // Size used   // (); // Unused size   UsbFile root  = ();//Get the root directory   String deviceName = ();//Get device tag   return currentFs;
  } catch (Exception e) {
   ();
   return null;
  }
 }

 /**
   * Get the file and folder path of the USB drive
   * @param fileSystem
   * @return
   */
 public List<UsbFile> getUsbFiles(FileSystem fileSystem) {
  ();
  try {
   for (UsbFile file : ()
           .listFiles()) { //Add so file and folder paths to the usbFiles array    (file);
   }
   (usbFiles, new Comparator<UsbFile>() {//Simple sorting Folders in front Files in back    @Override
    public int compare(UsbFile oFile1, UsbFile oFile2) {
     return ()
       ? -1
       : 1;
    }
   });
  } catch (IOException e) {
   ();
  }
  return usbFiles;
 }


 private BroadcastReceiver UDiskMountedReceiver = new BroadcastReceiver() {
  @Override
  public void onReceive(Context context, Intent intent) {
   String action = ();
   switch (action) {
    case ACTION_USB_PERMISSION: //Custom permission broadcast     if (mOnUDiskCallBack != null) {
      ();
     }
     break;
    case UsbManager.ACTION_USB_DEVICE_ATTACHED: //The USB device inserts the broadcast     if (mOnUDiskCallBack != null) {
      ();
     }
     break;

    case UsbManager.ACTION_USB_DEVICE_DETACHED: //Usb device unbroadcast     if (mOnUDiskCallBack != null) {
      ();
     }
     break;
   }
  }
 };
}