public class MainActivity extends AppCompatActivity implements View.OnClickListener {  //輸入的內(nèi)容  private EditText u_disk_edt;  //寫入到U盤  private Button u_disk_write;  //從U盤讀取  private Button u_disk_read;  //顯示讀取的內(nèi)容  private TextView u_disk_show;  //自定義U盤讀寫權(quán)限  private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";  //當(dāng)前處接U盤列表  private UsbMassStorageDevice[] storageDevices;  //當(dāng)前U盤所在文件目錄  private UsbFile cFolder;  private final static String U_DISK_FILE_NAME = "u_disk.txt";  private Handler mHandler = new Handler() {    @Override    public void handleMessage(Message msg) {      switch (msg.what) {        case 100:          showToastMsg("保存成功");          break;        case 101:          String txt = msg.obj.toString();          if (!TextUtils.isEmpty(txt))            u_disk_show.setText("讀取到的數(shù)據(jù)是：" + txt);          break;      }    }  };  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    initViews();  }  private void initViews() {    u_disk_edt = (EditText) findViewById(R.id.u_disk_edt);    u_disk_write = (Button) findViewById(R.id.u_disk_write);    u_disk_read = (Button) findViewById(R.id.u_disk_read);    u_disk_show = (TextView) findViewById(R.id.u_disk_show);    u_disk_write.setOnClickListener(this);    u_disk_read.setOnClickListener(this);  }  @Override  public void onClick(View view) {    switch (view.getId()) {      case R.id.u_disk_write:        final String content = u_disk_edt.getText().toString().trim();        mHandler.post(new Runnable() {          @Override          public void run() {            saveText2UDisk(content);          }        });        break;      case R.id.u_disk_read:        mHandler.post(new Runnable() {          @Override          public void run() {            readFromUDisk();          }        });        break;    }  }  private void readFromUDisk() {    UsbFile[] usbFiles = new UsbFile[0];    try {      usbFiles = cFolder.listFiles();    } catch (IOException e) {      e.printStackTrace();    }    if (null != usbFiles && usbFiles.length > 0) {      for (UsbFile usbFile : usbFiles) {        if (usbFile.getName().equals(U_DISK_FILE_NAME)) {          readTxtFromUDisk(usbFile);        }      }    }  }  /**   * @description 保存數(shù)據(jù)到U盤，目前是保存到根目錄的   * @author ldm   * @time 2017/9/1 17:17   */  private void saveText2UDisk(String content) {    //項(xiàng)目中也把文件保存在了SD卡，其實(shí)可以直接把文本讀取到U盤指定文件    File file = FileUtil.getSaveFile(getPackageName()            + File.separator + FileUtil.DEFAULT_BIN_DIR,        U_DISK_FILE_NAME);    try {      FileWriter fw = new FileWriter(file);      fw.write(content);      fw.close();    } catch (IOException e) {      e.printStackTrace();    }    if (null != cFolder) {      FileUtil.saveSDFile2OTG(file, cFolder);      mHandler.sendEmptyMessage(100);    }  }  /**   * @description OTG廣播注冊   * @author ldm   * @time 2017/9/1 17:19   */  private void registerUDiskReceiver() {    //監(jiān)聽otg插入 拔出    IntentFilter usbDeviceStateFilter = new IntentFilter();    usbDeviceStateFilter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);    usbDeviceStateFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);    registerReceiver(mOtgReceiver, usbDeviceStateFilter);    //注冊監(jiān)聽自定義廣播    IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);    registerReceiver(mOtgReceiver, filter);  }  /**   * @description OTG廣播，監(jiān)聽U盤的插入及拔出   * @author ldm   * @time 2017/9/1 17:20   * @param   */  private BroadcastReceiver mOtgReceiver = new BroadcastReceiver() {    public void onReceive(Context context, Intent intent) {      String action = intent.getAction();      switch (action) {        case ACTION_USB_PERMISSION://接受到自定義廣播          UsbDevice usbDevice = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);          //允許權(quán)限申請          if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {            if (usbDevice != null) {              //用戶已授權(quán)，可以進(jìn)行讀取操作              readDevice(getUsbMass(usbDevice));            } else {              showToastMsg("沒有插入U盤");            }          } else {            showToastMsg("未獲取到U盤權(quán)限");          }          break;        case UsbManager.ACTION_USB_DEVICE_ATTACHED://接收到U盤設(shè)備插入廣播          UsbDevice device_add = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);          if (device_add != null) {            //接收到U盤插入廣播，嘗試讀取U盤設(shè)備數(shù)據(jù)            redUDiskDevsList();          }          break;        case UsbManager.ACTION_USB_DEVICE_DETACHED://接收到U盤設(shè)設(shè)備拔出廣播          showToastMsg("U盤已拔出");          break;      }    }  };  /**   * @description U盤設(shè)備讀取   * @author ldm   * @time 2017/9/1 17:20   */  private void redUDiskDevsList() {    //設(shè)備管理器    UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);    //獲取U盤存儲設(shè)備    storageDevices = UsbMassStorageDevice.getMassStorageDevices(this);    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);    //一般手機(jī)只有1個OTG插口    for (UsbMassStorageDevice device : storageDevices) {      //讀取設(shè)備是否有權(quán)限      if (usbManager.hasPermission(device.getUsbDevice())) {        readDevice(device);      } else {        //沒有權(quán)限，進(jìn)行申請        usbManager.requestPermission(device.getUsbDevice(), pendingIntent);      }    }    if (storageDevices.length == 0) {      showToastMsg("請插入可用的U盤");    }  }  private UsbMassStorageDevice getUsbMass(UsbDevice usbDevice) {    for (UsbMassStorageDevice device : storageDevices) {      if (usbDevice.equals(device.getUsbDevice())) {        return device;      }    }    return null;  }  private void readDevice(UsbMassStorageDevice device) {    try {      device.init();//初始化      //設(shè)備分區(qū)      Partition partition = device.getPartitions().get(0);      //文件系統(tǒng)      FileSystem currentFs = partition.getFileSystem();      currentFs.getVolumeLabel();//可以獲取到設(shè)備的標(biāo)識      //通過FileSystem可以獲取當(dāng)前U盤的一些存儲信息，包括剩余空間大小，容量等等      Log.e("Capacity: ", currentFs.getCapacity() + "");      Log.e("Occupied Space: ", currentFs.getOccupiedSpace() + "");      Log.e("Free Space: ", currentFs.getFreeSpace() + "");      Log.e("Chunk size: ", currentFs.getChunkSize() + "");      cFolder = currentFs.getRootDirectory();//設(shè)置當(dāng)前文件對象為根目錄    } catch (Exception e) {      e.printStackTrace();    }  }  private void showToastMsg(String msg) {    Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();  }  private void readTxtFromUDisk(UsbFile usbFile) {    UsbFile descFile = usbFile;    //讀取文件內(nèi)容    InputStream is = new UsbFileInputStream(descFile);    //讀取秘鑰中的數(shù)據(jù)進(jìn)行匹配    StringBuilder sb = new StringBuilder();    BufferedReader bufferedReader = null;    try {      bufferedReader = new BufferedReader(new InputStreamReader(is));      String read;      while ((read = bufferedReader.readLine()) != null) {        sb.append(read);      }      Message msg = mHandler.obtainMessage();      msg.what = 101;      msg.obj = read;      mHandler.sendMessage(msg);    } catch (Exception e) {      e.printStackTrace();    } finally {      try {        if (bufferedReader != null) {          bufferedReader.close();        }      } catch (IOException e) {        e.printStackTrace();      }    }  }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.ldm.androidudisk.MainActivity"    android:orientation="vertical">  <TextView      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:text="Android盒子外接U盤文件讀寫測試DEMO"      android:layout_gravity="center"      android:layout_margin="10dp"      />  <EditText      android:id="@+id/u_disk_edt"      android:layout_width="match_parent"      android:layout_height="wrap_content"      android:layout_margin="10dp"      android:hint="輸入要保存到U盤中的文字內(nèi)容"/>  <Button      android:id="@+id/u_disk_write"      android:layout_width="match_parent"      android:layout_height="wrap_content"      android:layout_margin="10dp"      android:gravity="center"      android:text="往U盤中寫入數(shù)據(jù)"/>  <Button      android:id="@+id/u_disk_read"      android:layout_width="match_parent"      android:layout_height="wrap_content"      android:layout_margin="10dp"      android:gravity="center"      android:text="從U盤中讀取數(shù)據(jù)"/>  <TextView      android:id="@+id/u_disk_show"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:layout_gravity="center"      android:layout_marginLeft="10dp"      /></LinearLayout>

package com.ldm.androidudisk.utils;import android.os.Environment;import com.github.mjdev.libaums.fs.UsbFile;import com.github.mjdev.libaums.fs.UsbFileOutputStream;import java.io.Closeable;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import static android.os.Environment.getExternalStorageDirectory;/** * 文件操作工具類 * * @author ldm * @description： * @date 2016-4-28 下午3:17:10 */public final class FileUtil {  public static final String DEFAULT_BIN_DIR = "usb";  /**   * 檢測SD卡是否存在   */  public static boolean checkSDcard() {    return Environment.MEDIA_MOUNTED.equals(Environment        .getExternalStorageState());  }  /**   * 從指定文件夾獲取文件   *   * @return 如果文件不存在則創(chuàng)建, 如果如果無法創(chuàng)建文件或文件名為空則返回null   */  public static File getSaveFile(String folderPath, String fileNmae) {    File file = new File(getSavePath(folderPath) + File.separator        + fileNmae);    try {      file.createNewFile();    } catch (IOException e) {      e.printStackTrace();    }    return file;  }  /**   * 獲取SD卡下指定文件夾的絕對路徑   *   * @return 返回SD卡下的指定文件夾的絕對路徑   */  public static String getSavePath(String folderName) {    return getSaveFolder(folderName).getAbsolutePath();  }  /**   * 獲取文件夾對象   *   * @return 返回SD卡下的指定文件夾對象，若文件夾不存在則創(chuàng)建   */  public static File getSaveFolder(String folderName) {    File file = new File(getExternalStorageDirectory()        .getAbsoluteFile()        + File.separator        + folderName        + File.separator);    file.mkdirs();    return file;  }  /**   * 關(guān)閉流   */  public static void closeIO(Closeable... closeables) {    if (null == closeables || closeables.length <= 0) {      return;    }    for (Closeable cb : closeables) {      try {        if (null == cb) {          continue;        }        cb.close();      } catch (IOException e) {        e.printStackTrace();      }    }  }  private static void redFileStream(OutputStream os, InputStream is) throws IOException {    int bytesRead = 0;    byte[] buffer = new byte[1024 * 8];    while ((bytesRead = is.read(buffer)) != -1) {      os.write(buffer, 0, bytesRead);    }    os.flush();    os.close();    is.close();  }  /**   * @description 把本地文件寫入到U盤中   * @author ldm   * @time 2017/8/22 10:22   */  public static void saveSDFile2OTG(final File f, final UsbFile usbFile) {    UsbFile uFile = null;    FileInputStream fis = null;    try {//開始寫入      fis = new FileInputStream(f);//讀取選擇的文件的      if (usbFile.isDirectory()) {//如果選擇是個文件夾        UsbFile[] usbFiles = usbFile.listFiles();        if (usbFiles != null && usbFiles.length > 0) {          for (UsbFile file : usbFiles) {            if (file.getName().equals(f.getName())) {              file.delete();            }          }        }        uFile = usbFile.createFile(f.getName());        UsbFileOutputStream uos = new UsbFileOutputStream(uFile);        try {          redFileStream(uos, fis);        } catch (IOException e) {          e.printStackTrace();        }      }    } catch (final Exception e) {      e.printStackTrace();    }  }}

compile 'com.github.mjdev:libaums:0.5.5'

 <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>