有没有一种通用的方法来找到外置SD卡的位置?

请不要与外部存储混淆。

Environment.getExternalStorageState()返回内部SD挂载点的路径,例如/mnt/sdcard。但问题是关于外部SD的。我如何获得类似/mnt/sdcard/external_sd的路径(它可能因设备而异)?

我想我将以根据文件系统名称过滤mount命令的输出作为结束。但我不确定这种方式是否足够稳健。


当前回答

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。

其他回答

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;
    }    
}

根据这里找到的一些答案,我想出了以下解决方案。

代码:

public class ExternalStorage {

    public static final String SD_CARD = "sdCard";
    public static final String EXTERNAL_SD_CARD = "externalSdCard";

    /**
     * @return True if the external storage is available. False otherwise.
     */
    public static boolean isAvailable() {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state) || Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
            return true;
        }
        return false;
    }

    public static String getSdCardPath() {
        return Environment.getExternalStorageDirectory().getPath() + "/";
    }

    /**
     * @return True if the external storage is writable. False otherwise.
     */
    public static boolean isWritable() {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            return true;
        }
        return false;

    }

    /**
     * @return A map of all storage locations available
     */
    public static Map<String, File> getAllStorageLocations() {
        Map<String, File> map = new HashMap<String, File>(10);

        List<String> mMounts = new ArrayList<String>(10);
        List<String> mVold = new ArrayList<String>(10);
        mMounts.add("/mnt/sdcard");
        mVold.add("/mnt/sdcard");

        try {
            File mountFile = new File("/proc/mounts");
            if(mountFile.exists()){
                Scanner scanner = new Scanner(mountFile);
                while (scanner.hasNext()) {
                    String line = scanner.nextLine();
                    if (line.startsWith("/dev/block/vold/")) {
                        String[] lineElements = line.split(" ");
                        String element = lineElements[1];

                        // don't add the default mount path
                        // it's already in the list.
                        if (!element.equals("/mnt/sdcard"))
                            mMounts.add(element);
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        try {
            File voldFile = new File("/system/etc/vold.fstab");
            if(voldFile.exists()){
                Scanner scanner = new Scanner(voldFile);
                while (scanner.hasNext()) {
                    String line = scanner.nextLine();
                    if (line.startsWith("dev_mount")) {
                        String[] lineElements = line.split(" ");
                        String element = lineElements[2];

                        if (element.contains(":"))
                            element = element.substring(0, element.indexOf(":"));
                        if (!element.equals("/mnt/sdcard"))
                            mVold.add(element);
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }


        for (int i = 0; i < mMounts.size(); i++) {
            String mount = mMounts.get(i);
            if (!mVold.contains(mount))
                mMounts.remove(i--);
        }
        mVold.clear();

        List<String> mountHash = new ArrayList<String>(10);

        for(String mount : mMounts){
            File root = new File(mount);
            if (root.exists() && root.isDirectory() && root.canWrite()) {
                File[] list = root.listFiles();
                String hash = "[";
                if(list!=null){
                    for(File f : list){
                        hash += f.getName().hashCode()+":"+f.length()+", ";
                    }
                }
                hash += "]";
                if(!mountHash.contains(hash)){
                    String key = SD_CARD + "_" + map.size();
                    if (map.size() == 0) {
                        key = SD_CARD;
                    } else if (map.size() == 1) {
                        key = EXTERNAL_SD_CARD;
                    }
                    mountHash.add(hash);
                    map.put(key, root);
                }
            }
        }

        mMounts.clear();

        if(map.isEmpty()){
                 map.put(SD_CARD, Environment.getExternalStorageDirectory());
        }
        return map;
    }
}

用法:

Map<String, File> externalLocations = ExternalStorage.getAllStorageLocations();
File sdCard = externalLocations.get(ExternalStorage.SD_CARD);
File externalSdCard = externalLocations.get(ExternalStorage.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;
}

这么晚了,但最终我得到了一些东西,我已经测试了大多数设备(通过制造商和android版本),它在android 2.2+上工作。如果您发现它不起作用,请用您的设备名称注释它。我会解决的。如果有人感兴趣,我会解释它是如何工作的。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;

import android.util.Log;


/**
 * @author ajeet
 *05-Dec-2014  2014
 *
 */
public class StorageUtil {

    public boolean isRemovebleSDCardMounted() {
        File file = new File("/sys/class/block/");
        File[] files = file.listFiles(new MmcblkFilter("mmcblk\\d$"));
        boolean flag = false;
        for (File mmcfile : files) {
            File scrfile = new File(mmcfile, "device/scr");
            if (scrfile.exists()) {
                flag = true;
                break;
            }
        }
        return flag;
    }

    public String getRemovebleSDCardPath() throws IOException {
        String sdpath = null;
        File file = new File("/sys/class/block/");
        File[] files = file.listFiles(new MmcblkFilter("mmcblk\\d$"));
        String sdcardDevfile = null;
        for (File mmcfile : files) {
            Log.d("SDCARD", mmcfile.getAbsolutePath());
            File scrfile = new File(mmcfile, "device/scr");
            if (scrfile.exists()) {
                sdcardDevfile = mmcfile.getName();
                Log.d("SDCARD", mmcfile.getName());
                break;
            }
        }
        if (sdcardDevfile == null) {
            return null;
        }
        FileInputStream is;
        BufferedReader reader;

        files = file.listFiles(new MmcblkFilter(sdcardDevfile + "p\\d+"));
        String deviceName = null;
        if (files.length > 0) {
            Log.d("SDCARD", files[0].getAbsolutePath());
            File devfile = new File(files[0], "dev");
            if (devfile.exists()) {
                FileInputStream fis = new FileInputStream(devfile);
                reader = new BufferedReader(new InputStreamReader(fis));
                String line = reader.readLine();
                deviceName = line;
            }
            Log.d("SDCARD", "" + deviceName);
            if (deviceName == null) {
                return null;
            }
            Log.d("SDCARD", deviceName);

            final File mountFile = new File("/proc/self/mountinfo");

            if (mountFile.exists()) {
                is = new FileInputStream(mountFile);
                reader = new BufferedReader(new InputStreamReader(is));
                String line = null;
                while ((line = reader.readLine()) != null) {
                    // Log.d("SDCARD", line);
                    // line = reader.readLine();
                    // Log.d("SDCARD", line);
                    String[] mPonts = line.split("\\s+");
                    if (mPonts.length > 6) {
                        if (mPonts[2].trim().equalsIgnoreCase(deviceName)) {
                            if (mPonts[4].contains(".android_secure")
                                    || mPonts[4].contains("asec")) {
                                continue;
                            }
                            sdpath = mPonts[4];
                            Log.d("SDCARD", mPonts[4]);

                        }
                    }

                }
            }

        }

        return sdpath;
    }

    static class MmcblkFilter implements FilenameFilter {
        private String pattern;

        public MmcblkFilter(String pattern) {
            this.pattern = pattern;

        }

        @Override
        public boolean accept(File dir, String filename) {
            if (filename.matches(pattern)) {
                return true;
            }
            return false;
        }

    }

}

这次我尝试了这个主题内的所有解决方案。但是,在有一个外置卡(可移动)和一个内置卡(不可移动)的设备上,所有这些设备都不能正常工作。外部卡的路径不可能从'mount'命令,从'proc/mounts'文件等。

我在Paulo Luan的基础上提出了自己的解决方案:

String sSDpath = null;
File   fileCur = null;
for( String sPathCur : Arrays.asList( "ext_card", "external_sd", "ext_sd", "external", "extSdCard",  "externalSdCard")) // external sdcard
{
   fileCur = new File( "/mnt/", sPathCur);
   if( fileCur.isDirectory() && fileCur.canWrite())
   {
     sSDpath = fileCur.getAbsolutePath();
     break;
   }
}
fileCur = null;
if( sSDpath == null)  sSDpath = Environment.getExternalStorageDirectory().getAbsolutePath();