通过编写下面的代码，您将获得位置:

数据存储663D-554E / Android / app_package_name / files /

存储你的应用程序数据在/android/数据位置内的sd_card。

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

list[1]+"/fol" 

对于获取位置，内部传递0,sdcard传递1到文件数组。

我已经在moto g4 plus和三星设备上测试了这段代码(一切正常)。

希望这对你有所帮助。

我已经创建了一个utils方法来检查SD卡在设备上是否可用，并获得设备上的SD卡路径(如果可用)。

你可以复制2方法波纹到你的项目的类，你需要。这是所有。

public String isRemovableSDCardAvailable() {
    final String FLAG = "mnt";
    final String SECONDARY_STORAGE = System.getenv("SECONDARY_STORAGE");
    final String EXTERNAL_STORAGE_DOCOMO = System.getenv("EXTERNAL_STORAGE_DOCOMO");
    final String EXTERNAL_SDCARD_STORAGE = System.getenv("EXTERNAL_SDCARD_STORAGE");
    final String EXTERNAL_SD_STORAGE = System.getenv("EXTERNAL_SD_STORAGE");
    final String EXTERNAL_STORAGE = System.getenv("EXTERNAL_STORAGE");

    Map<Integer, String> listEnvironmentVariableStoreSDCardRootDirectory = new HashMap<Integer, String>();
    listEnvironmentVariableStoreSDCardRootDirectory.put(0, SECONDARY_STORAGE);
    listEnvironmentVariableStoreSDCardRootDirectory.put(1, EXTERNAL_STORAGE_DOCOMO);
    listEnvironmentVariableStoreSDCardRootDirectory.put(2, EXTERNAL_SDCARD_STORAGE);
    listEnvironmentVariableStoreSDCardRootDirectory.put(3, EXTERNAL_SD_STORAGE);
    listEnvironmentVariableStoreSDCardRootDirectory.put(4, EXTERNAL_STORAGE);

    File externalStorageList[] = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
        externalStorageList = getContext().getExternalFilesDirs(null);
    }
    String directory = null;
    int size = listEnvironmentVariableStoreSDCardRootDirectory.size();
    for (int i = 0; i < size; i++) {
        if (externalStorageList != null && externalStorageList.length > 1 && externalStorageList[1] != null)
            directory = externalStorageList[1].getAbsolutePath();
        else
            directory = listEnvironmentVariableStoreSDCardRootDirectory.get(i);

        directory = canCreateFile(directory);
        if (directory != null && directory.length() != 0) {
            if (i == size - 1) {
                if (directory.contains(FLAG)) {
                    Log.e(getClass().getSimpleName(), "SD Card's directory: " + directory);
                    return directory;
                } else {
                    return null;
                }
            }
            Log.e(getClass().getSimpleName(), "SD Card's directory: " + directory);
            return directory;
        }
    }
    return null;
}

/**
 * Check if can create file on given directory. Use this enclose with method
 * {@link BeginScreenFragement#isRemovableSDCardAvailable()} to check sd
 * card is available on device or not.
 * 
 * @param directory
 * @return
 */
public String canCreateFile(String directory) {
    final String FILE_DIR = directory + File.separator + "hoang.txt";
    File tempFlie = null;
    try {
        tempFlie = new File(FILE_DIR);
        FileOutputStream fos = new FileOutputStream(tempFlie);
        fos.write(new byte[1024]);
        fos.flush();
        fos.close();
        Log.e(getClass().getSimpleName(), "Can write file on this directory: " + FILE_DIR);
    } catch (Exception e) {
        Log.e(getClass().getSimpleName(), "Write file error: " + e.getMessage());
        return null;
    } finally {
        if (tempFlie != null && tempFlie.exists() && tempFlie.isFile()) {
            // tempFlie.delete();
            tempFlie = null;
        }
    }
    return directory;
}

我不知道为什么，但我需要在使用它之前在公共存储目录中创建的文件上调用. createnewfile()。在框架中，该方法的注释说它没有用。这是一个样本……

String myPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PODCASTS) + File. txt文件。separator +“我的目录”; final File myDir = new File(myypath); 尝试{ myDir.mkdirs (); } catch(异常ex) { 吐司。makeText(this， "error: " + ex.getMessage()， Toast.LENGTH_LONG).show(); ｝

        String fname = "whatever";
        File newFile = new File(myDir, fname);

        Log.i(TAG, "File exists --> " + newFile.exists()) //will be false  
    try {
            if (newFile.createNewFile()) {

                 //continue 

              } else {

                Log.e(TAG, "error creating file");

            }

        } catch (Exception e) {
            Log.e(TAG, e.toString());
        }

这是我用来找到外部卡的方法。使用mount cmd返回然后解析vfat部分。

String s = "";
try {
Process process = new ProcessBuilder().command("mount")
        .redirectErrorStream(true).start();

process.waitFor();

InputStream is = process.getInputStream();
byte[] buffer = new byte[1024];
while (is.read(buffer) != -1) {
    s = s + new String(buffer);
}
is.close();
} catch (Exception e) {
e.printStackTrace();
}

//用行分隔mount列表
String[] lines = s.split("\n");
for(int i=0; i<lines.length; i++) {
//如果行内有挂载路径且为vfat类型，说明可能是内置或者外置sd的挂载点
if(-1 != lines[i].indexOf(path[0]) && -1 != lines[i].indexOf("vfat")) {
    //再用空格分隔
    String[] blocks = lines[i].split("\\s");
    for(int j=0; j<blocks.length; j++) {
        //判断是否是挂载为vfat类型
        if(-1 != blocks[j].indexOf(path[0])) {
            //Test if it is the external sd card.
        }
    }
}
}

我找到的唯一有效的解决方案是使用反射

 /**
 * Get external sd card path using reflection
 * @param mContext
 * @param is_removable is external storage removable
 * @return
 */
private static String getExternalStoragePath(Context mContext, boolean is_removable) {

    StorageManager mStorageManager = (StorageManager) mContext.getSystemService(Context.STORAGE_SERVICE);
    Class<?> storageVolumeClazz = null;
    try {
        storageVolumeClazz = Class.forName("android.os.storage.StorageVolume");
        Method getVolumeList = mStorageManager.getClass().getMethod("getVolumeList");
        Method getPath = storageVolumeClazz.getMethod("getPath");
        Method isRemovable = storageVolumeClazz.getMethod("isRemovable");
        Object result = getVolumeList.invoke(mStorageManager);
        final int length = Array.getLength(result);
        for (int i = 0; i < length; i++) {
            Object storageVolumeElement = Array.get(result, i);
            String path = (String) getPath.invoke(storageVolumeElement);
            boolean removable = (Boolean) isRemovable.invoke(storageVolumeElement);
            if (is_removable == removable) {
                return path;
            }
        }
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
    return null;
}

像Richard一样，我也使用/proc/mounts文件来获取可用的存储选项列表

public class StorageUtils {

    private static final String TAG = "StorageUtils";

    public static class StorageInfo {

        public final String path;
        public final boolean internal;
        public final boolean readonly;
        public final int display_number;

        StorageInfo(String path, boolean internal, boolean readonly, int display_number) {
            this.path = path;
            this.internal = internal;
            this.readonly = readonly;
            this.display_number = display_number;
        }

        public String getDisplayName() {
            StringBuilder res = new StringBuilder();
            if (internal) {
                res.append("Internal SD card");
            } else if (display_number > 1) {
                res.append("SD card " + display_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_internal = !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);
        BufferedReader buf_reader = null;
        try {
            HashSet<String> paths = new HashSet<String>();
            buf_reader = new BufferedReader(new FileReader("/proc/mounts"));
            String line;
            int cur_display_number = 1;
            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 (mount_point.equals(def_path)) {
                        paths.add(def_path);
                        list.add(0, new StorageInfo(def_path, def_path_internal, readonly, -1));
                    } else 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, false, readonly, cur_display_number++));
                        }
                    }
                }
            }

            if (!paths.contains(def_path) && def_path_available) {
                list.add(0, new StorageInfo(def_path, def_path_internal, def_path_readonly, -1));
            }

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