Android的外部SDCard文件路径

Question

Android设备上外部SDCard的文件路径始终是"/ storage/extSdCard"吗？如果没有,有多少变化？

我需要它来为我的应用程序测试外部 SD卡的可用性.

我正在使用Titanium,它有一个方法Titanium.Filesystem.isExternalStoragePresent() 但它总是返回true,即使没有安装外部SDCard.

我认为它在本地存储中检测到SDCard因此返回true.但我真正想要的是检测物理SD卡是否已安装.

我可以通过单独检测文件"/ storage/extSdCard"的存在来做到这一点吗？

谢谢.

Answer 1

Android设备上外部SDCard的文件路径始终是"/ storage/extSdCard"吗？如果没有,有多少变化？

遗憾的是,根据制造商的说法,外部存储器的路径并不总是相同.使用Environment.getExternalStorageDirectory()将返回SD卡的正常路径mnt/sdcard/.但是对于三星设备,例如,SD卡路径是低于mnt/extSdCard/或低于mnt/external_sd/.

因此,一种方法是根据每个制造商使用的路径检查外部目录的存在.有这样的事情:

mExternalDirectory = Environment.getExternalStorageDirectory()
            .getAbsolutePath();
    if (android.os.Build.DEVICE.contains("samsung")
            || android.os.Build.MANUFACTURER.contains("samsung")) {
        File f = new File(Environment.getExternalStorageDirectory()
                .getParent() + "/extSdCard" + "/myDirectory");
        if (f.exists() && f.isDirectory()) {
            mExternalDirectory = Environment.getExternalStorageDirectory()
                    .getParent() + "/extSdCard";
        } else {
            f = new File(Environment.getExternalStorageDirectory()
                    .getAbsolutePath() + "/external_sd" + "/myDirectory");  
            if (f.exists() && f.isDirectory()) {
                mExternalDirectory = Environment
                        .getExternalStorageDirectory().getAbsolutePath()
                        + "/external_sd";
            }
        }
    }

但我真正想要的是检测物理SD卡是否已安装.

我还没有尝试过代码,但Dmitriy Lozenko在这个答案中的方法更有趣.无论制造商如何,他的方法都会返回系统上所有已安装SD卡的路径.

Answer 2

我希望它对你有用:)

import android.os.Environment;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;


public class MemoryStorage {

    private MemoryStorage() {}

    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;
    }
}

Answer 3

这就是我最终使用以下方法获得 sdcard 路径的方式：

public String getExternalStoragePath() {

        String internalPath = Environment.getExternalStorageDirectory().getAbsolutePath();
        String[] paths = internalPath.split("/");
        String parentPath = "/";
        for (String s : paths) {
            if (s.trim().length() > 0) {
                parentPath = parentPath.concat(s);
                break;
            }
        }
        File parent = new File(parentPath);
        if (parent.exists()) {
            File[] files = parent.listFiles();
            for (File file : files) {
                String filePath = file.getAbsolutePath();
                Log.d(TAG, filePath);
                if (filePath.equals(internalPath)) {
                    continue;
                } else if (filePath.toLowerCase().contains("sdcard")) {
                    return filePath;
                } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    try {
                        if (Environment.isExternalStorageRemovable(file)) {
                            return filePath;
                        }
                    } catch (RuntimeException e) {
                        Log.e(TAG, "RuntimeException: " + e);
                    }
                }
            }

        }
        return null;
    }