model如下,功能一目了然:

public class FileInfo {
    // id value in DB
    public long id;
    // true if file is a directory
    public boolean isDir;
    // true if file is hidden
    public boolean isHidden;
    // full name of the file
    public String fileName;
    // the path which the file in
    public String filePath;
    // file size in bytes
    public long fileSize;
    // last modified timestamp
    public long modifiedTimeMillis;
    // icon (adoptable）
    public Drawable icon;
    public boolean hasThumb;
    //if isDir is true, get file count in this dir
    public int fileCount;
    //resolution of pictures
    public int height = 0;
    public int width = 0;

    public static FileInfo createInfo(File file, final boolean includeHidden) {
        FileInfo info = new FileInfo();
        if (file == null) {
            return info;
        }
        try {
            info.filePath = file.getCanonicalPath();
        } catch (IOException e) {
            e.printStackTrace();
            info.filePath = file.getAbsolutePath();
        }
        info.fileName = file.getName();
        info.fileSize = file.length();
        info.modifiedTimeMillis = file.lastModified();
        info.isDir = file.isDirectory();
        info.isHidden = file.isHidden();
        info.fileCount = 0;
        if (info.isDir) {
            File[] list = file.listFiles(new FilenameFilter() {
                @Override
                public boolean accept(File dir, String filename) {
                    if (!includeHidden && filename.startsWith(".")) {
                        return false;
                    }
                    return true;
                }
            });
            if (list != null) {
                info.fileCount = list.length;
            }
        } else {
            info.hasThumb = ThumbUtils.getThumbnailType(file) != null;
        }
        return info;
    }
}

获取内外置存储卡,OTG路径的方法(使用反射):

private List<FileInfo> goGetStorages() {
        List<FileInfo> list = new ArrayList<>();
        StorageManager sm = (StorageManager) mApplication.getSystemService(Context.STORAGE_SERVICE);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            Class<?> klass = StorageVolume.class;
            try {
                Method method = klass.getMethod("getPathFile");
                List<StorageVolume> volumes = sm.getStorageVolumes();
                for (StorageVolume volume : volumes) {
                    FileInfo info = FileInfo.createInfo((File) method.invoke(volume), true);
                    info.fileName = volume.getDescription(mApplication);
                    list.add(info);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            try {
                Class<?> klass = StorageManager.class;
                Method method = klass.getMethod("getVolumePaths");
                String[] paths = (String[]) method.invoke(sm);
                if (paths != null) {
                    for (String path : paths) {
                        list.add(FileInfo.createInfo(new File(path), true));
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return list;
    }