三方库
implementation 'me.jahnen:libaums:0.7.6'
权限
Note:Android 10 需要在Application标签中添加一条 android:requestLegacyExternalStorage="true" ,用于使用遗留存储权限，据说是因为安全原因。
帮助类
这里主要是用于读写图片的，如果只写文件就更简单了
/**
* created by Taoyuan on 2020/10/26
* USB帮助类
*/
public class UsbUtils {
private Context context;
private UsbMassStorageDevice mDevice;
private UsbFile cFolder;
private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
// 文件目录
public static String appDir = "App";
public static String picDir = "picture";
public boolean mUSBisOK = false;
public UsbUtils(Context context) {
this.context = context;
init();
}
/**
* 初始化广播，用于监听权限和插拔USB
*/
private void init() {
// 权限广播
BroadcastReceiver mUsbPermissionActionReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (ACTION_USB_PERMISSION.equals(action)) {
context.unregisterReceiver(this);//解注册
synchronized (this) {
UsbDevice usbDevice = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
if (usbDevice != null) {
L.e(usbDevice.getDeviceName() + "已获取USB权限");
//接收到U盘插入广播，尝试读取U盘设备数据
mUSBisOK = readUsbList();//U盘已插入,并获取权限
}
} else {
L.e("USB权限已被拒绝，Permission denied for device" + usbDevice);
}
}
}
}
};
context.registerReceiver(mUsbPermissionActionReceiver, new IntentFilter(ACTION_USB_PERMISSION));
// otg插拔广播
BroadcastReceiver mOtgReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction() == null) return;
switch (intent.getAction()) {
case UsbManager.ACTION_USB_DEVICE_ATTACHED://接收到U盘设备插入广播
T.show(context, "U盘已插入");
UsbDevice device_add = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (device_add != null) {
//接收到U盘插入广播，尝试读取U盘设备数据
mUSBisOK = readUsbList();//U盘已插入
}
break;
case UsbManager.ACTION_USB_DEVICE_DETACHED://接收到U盘设设备拔出广播
T.show(context, "U盘已拔出");
mUSBisOK = readUsbList();//U盘已拔出
break;
}
}
};
//监听otg插入 拔出
IntentFilter usbDeviceStateFilter = new IntentFilter();
usbDeviceStateFilter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
usbDeviceStateFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
context.registerReceiver(mOtgReceiver, usbDeviceStateFilter);
}
/**
* 读取U盘列表
*
* @return 是否读取成功
*/
public boolean readUsbList() {
boolean isOK = false;
//设备管理器
UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
//获取U盘存储设备
UsbMassStorageDevice[] storageDevices = UsbMassStorageDevice.getMassStorageDevices(context);
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);
//一般手机只有1个OTG插口
for (UsbMassStorageDevice device : storageDevices) {
//读取设备是否有权限
if (usbManager == null) return false;
if (usbManager.hasPermission(device.getUsbDevice())) {
isOK = readDevice(device);
} else {
//没有权限，进行申请
usbManager.requestPermission(device.getUsbDevice(), pendingIntent);
}
}
if (storageDevices.length == 0) {
T.show(context, "请插入可用的U盘");
}
return isOK;
}
/**
* 读取设备(需已申请权限)
*
* @param device usb设备
* @return 是否读取成功
*/
private boolean readDevice(UsbMassStorageDevice device) {
try {
mDevice = device;
mDevice.init();
// 一般U盘只有一个分区，在android 10 实测时，只有FAT32可以被读取
if (mDevice.getPartitions().size() == 0) {
T.show(context, "读取设备分区失败");
return false;
} else {
T.show(context, "U盘已就绪");
FileSystem currentFs = mDevice.getPartitions().get(0).getFileSystem();
cFolder = currentFs.getRootDirectory();
return true;
}
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
/**
* 向USB写数据
*
* @param fileList 需要写入的文件
* @return 是否写入成功
*/
public boolean write(List fileList) {
try {
// 获取usb图片目录
UsbFile[] usbFiles = cFolder.listFiles();
UsbFile applicationDir = null;
UsbFile pictureDir = null;
// 判断目录是否存在，不存在则创建
for (UsbFile usbFile : usbFiles) {
if (usbFile.getName().equals(appDir)) {
applicationDir = usbFile;
}
}
// app目录不存在则创建
if (applicationDir == null) {
applicationDir = cFolder.createDirectory(appDir);
} else {
// 存在则遍历pic目录
for (UsbFile usbFile : applicationDir.listFiles()) {
if (usbFile.getName().equals(picDir)) {
pictureDir = usbFile;
}
}
}
if (pictureDir == null) {
pictureDir = applicationDir.createDirectory(picDir);
}
// 如果不存在则直接创建
if (pictureDir.listFiles().length > 0) {
// 如果存在，则先把重复文件从列表中清空一遍
for (UsbFile usbFile : pictureDir.listFiles()) {
for (int i = fileList.size() - 1; i >= 0; i--) {
if (fileList.get(i).getName().equals(usbFile.getName())) {
fileList.remove(i);
}
}
}
}
if (fileList.size() == 0) {
T.show(context, "选择文件已全部导出");
return false;
}
List usbFileList = new ArrayList<>();
for (File file : fileList) {
UsbFile file1 = pictureDir.createFile(file.getName());
usbFileList.add(file1);
}
for (UsbFile usbFile : usbFileList) {
for (int i = 0; i < fileList.size(); i++) {
if (fileList.get(i).getName().equals(usbFile.getName())) {
write2USB(fileList.get(i).getAbsolutePath(), usbFile);
}
}
}
mDevice.close();
return true;
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
/**
* 写文件
*
* @param source android设备中的文件路径
* @param target usb目标文件
*/
public void write2USB(String source, UsbFile target) {
try {
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(source));
UsbFileOutputStream usbos = new UsbFileOutputStream(target);
byte[] buffer = new byte[1024];
int len = -1;
while ((len = bis.read(buffer)) != -1) {
usbos.write(buffer, 0, len);
}
bis.close();
usbos.flush();
usbos.close();
} catch (java.io.FileNotFoundException e) {
L.e("The File doesn't not exist.");
} catch (IOException e) {
e.printStackTrace();
}
}
}
使用
UsbUtils usbUtils = new UsbUtils(this);
// 加载U盘
usbUtils.mUSBisOK = usbUtils.readUsbList();
// 使用动态目录
if (!usbUtils.mUSBisOK) {
T.show(this, "请先加载U盘");
return;
}
UsbUtils.picDir = text;
// 写文件
if (usbUtils.mUSBisOK) {
List fileList = new ArrayList<>();
for (String imgPath : mData) {
File file = FileUtils.getFileByPath(imgPath);
if (file.exists()) fileList.add(file);
}
boolean writeOK = usbUtils.write(fileList);
if (writeOK) T.show(
this,
"导出成功：" + UsbUtils.appDir + "/" + UsbUtils.picDir,
true);
}