如何获取Android设备的已安装外部存储列表

Question

在这里,我们正在为Android电视盒开发Android应用程序.如何获取已安装的外部存储列表USB stick, SDCARD and SATA HDD.

Answer 1

我使用/ proc/mounts文件来获取可用存储选项的列表

public class StorageUtils {

    private static final String TAG = "StorageUtils";

    public static class StorageInfo {

        public final String path;
        public final boolean readonly;
        public final boolean removable;     
        public final int number;

        StorageInfo(String path, boolean readonly, boolean removable, int number) {
            this.path = path;
            this.readonly = readonly;
            this.removable = removable;         
            this.number = number;
        }

        public String getDisplayName() {
            StringBuilder res = new StringBuilder();
            if (!removable) {
                res.append("Internal SD card");
            } else if (number > 1) {
                res.append("SD card " + number);
            } else {
                res.append("SD card");
            }
            if (readonly) {
                res.append(" (Read only)");
            }
            return res.toString();
        }
    }

    public static List<StorageInfo> getStorageList() {

        List<StorageInfo> list = new ArrayList<StorageInfo>();
        String def_path = Environment.getExternalStorageDirectory().getPath();
        boolean def_path_removable = Environment.isExternalStorageRemovable();
        String def_path_state = Environment.getExternalStorageState();
        boolean def_path_available = def_path_state.equals(Environment.MEDIA_MOUNTED)
                                    || def_path_state.equals(Environment.MEDIA_MOUNTED_READ_ONLY);
        boolean def_path_readonly = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED_READ_ONLY);

        HashSet<String> paths = new HashSet<String>();
        int cur_removable_number = 1;

        if (def_path_available) {
            paths.add(def_path);
            list.add(0, new StorageInfo(def_path, def_path_readonly, def_path_removable, def_path_removable ? cur_removable_number++ : -1));
        }

        BufferedReader buf_reader = null;
        try {
            buf_reader = new BufferedReader(new FileReader("/proc/mounts"));
            String line;
            Log.d(TAG, "/proc/mounts");
            while ((line = buf_reader.readLine()) != null) {
                Log.d(TAG, line);
                if (line.contains("vfat") || line.contains("/mnt")) {
                    StringTokenizer tokens = new StringTokenizer(line, " ");
                    String unused = tokens.nextToken(); //device
                    String mount_point = tokens.nextToken(); //mount point
                    if (paths.contains(mount_point)) {
                        continue;
                    }
                    unused = tokens.nextToken(); //file system
                    List<String> flags = Arrays.asList(tokens.nextToken().split(",")); //flags
                    boolean readonly = flags.contains("ro");

                    if (line.contains("/dev/block/vold")) {
                        if (!line.contains("/mnt/secure")
                            && !line.contains("/mnt/asec")
                            && !line.contains("/mnt/obb")
                            && !line.contains("/dev/mapper")
                            && !line.contains("tmpfs")) {
                            paths.add(mount_point);
                            list.add(new StorageInfo(mount_point, readonly, true, cur_removable_number++));
                        }
                    }
                }
            }

        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            if (buf_reader != null) {
                try {
                    buf_reader.close();
                } catch (IOException ex) {}
            }
        }
        return list;
    }
}

Answer 2

要获取所有可用的外部存储文件夹(包括SD卡),您可以使用以下命令:

File[] externalStorageFiles=ContextCompat.getExternalFilesDirs(this,null);

要转到每个外部存储的"根"(即真正的安装文件夹路径),您可以使用我所做的这个功能:

  /** Given any file/folder inside an sd card, this will return the path of the sd card */
  private static String getRootOfInnerSdCardFolder(File file)
    {
    if(file==null)
      return null;
    final long totalSpace=file.getTotalSpace();
    while(true)
      {
      final File parentFile=file.getParentFile();
      if(parentFile==null||parentFile.getTotalSpace()!=totalSpace)
        return file.getAbsolutePath();
      file=parentFile;
      }
    }

Answer 3

Environment.getExternalStorageState() 返回内部SD挂载点的路径,如"/ mnt/sdcard"

不,Environment.getExternalStorageDirectory()指设备制造商认为是"外部存储"的任何内容.在某些设备上,这是可移动媒体,如SD卡.在某些设备上,这是设备上闪存的一部分.这里,"外部存储"意味着"安装在主机上时通过USB大容量存储模式可访问的东西",至少对于Android 1.x和2.x.

但问题是关于外部SD.如何获得像"/ mnt/sdcard/external_sd"这样的路径(它可能因设备而异)？

除了外部存储之外,Android没有"外部SD"的概念,如上所述.

如果设备制造商已选择将外部存储设备作为板载闪存并且还具有SD卡,则需要与该制造商联系以确定是否可以使用SD卡(不保证)以及规则是什么使用它,比如使用它的路径.

试试这个:

的Manifest.xml:

<receiver android:name=".MyReceiver">
    <intent-filter>
         <action android:name="android.intent.action.ums_connected" />
     </intent-filter>
  </receiver>

Myreceiver:

public class MyReceiver extends BroadcastReceiver{
if (intent.getAction().equalsIgnoreCase(
        "android.intent.action.UMS_CONNECTED")) {...}
}

Answer 4

您可以使用getExternalStorageDirectory()来获取外部存储目录。该文档很好地解释了其用法http://developer.android.com/reference/android/os/Environment.html#getExternalStorageDirectory%28%29

对于 USB 设备，您可能需要查看该类UsbManager或更一般的android.hardware.usb http://developer.android.com/reference/android/hardware/usb/UsbManager.html