Question

如何检测具有otg兼容性的Android设备

我正在使用以下代码：

context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_USB_HOST);

对于非otg安卓设备

总是返回true

Answer 1

是的，它并不总是有效，某种错误。

通过otp连接USB设备，然后在app中使用UsbManager系统服务并通过连接的USB设备进行枚举：

 mUsbManager = (UsbManager) mApplicationContext.getSystemService(Context.USB_SERVICE);
 HashMap<String, UsbDevice> devlist = mUsbManager.getDeviceList();
 if(!devlist.isEmpty()){
    // Supports usb host...
 } else {
    // Does not supports usb host...
 }

不幸的是，这种方法需要硬件USB设备，我还没有找到任何其他可靠的软件检查来确认。

希望它有所帮助！

Answer 2

此解决方案始终适用于API级别24及以上：

第1步-询问使用辅助存储的权限：

StorageManager storageManager = (StorageManager) getSystemService(Context.STORAGE_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
     StorageVolume primaryVolume = storageManager.getPrimaryStorageVolume(); // This will gives primary storage like internal storage
     List<StorageVolume> lstStorages = storageManager.getStorageVolumes(); // it will gives all secondary storage like SDCrad and USb device list
     for (int i = 0; i < lstStorages.size(); i++) {
         Intent intent = lstStorages.get(i).createAccessIntent(null); // null pass for get full access of storage
         startActivityForResult(intent, 6000);
     }
}

步骤2 -授予权限后：

protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
     super.onActivityResult(requestCode, resultCode, data);
     if (requestCode == 6000 && resultCode == RESULT_OK) {
         Uri treeUri = data.getData();
         DocumentFile documentFile = DocumentFile.fromTreeUri(this, treeUri); //List of all documents files of secondary storage
         List<DocumentFile> lstChildren = Arrays.asList(documentFile.listFiles());
         getContentResolver().takePersistableUriPermission(treeUri, FLAG_GRANT_READ_URI_PERMISSION | FLAG_GRANT_WRITE_URI_PERMISSION); // It will not ask permission for every time
         for (DocumentFile documentFile1 : lstChildren) {
             getAllFiles(documentFile1);
         }
     }
}

第3步-获取所有文件：

private void getAllFiles(DocumentFile documentFile) {
    DocumentFile[] files;
    files = documentFile.listFiles();
    for (DocumentFile file : files) {
        if (file.isDirectory()) {
            getAllFiles(file);
        } else {
            lstFiles.add(new UsbFileModel(documentFile, file.getUri()));
        }
    }
}

Android usb host-otg检测

2 个答案: