/**
  * 读取手机中所有图片信息
  */
 private void getAllPhotoInfo() {
  new Thread(new Runnable() {
   @Override
   public void run() {
    List<MediaBean> mediaBeen = new ArrayList<>();
    HashMap<String,List<MediaBean>> allPhotosTemp = new HashMap<>();//所有照片
    Uri mImageUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    String[] projImage = { MediaStore.Images.Media._ID
      , MediaStore.Images.Media.DATA
      ,MediaStore.Images.Media.SIZE
      ,MediaStore.Images.Media.DISPLAY_NAME};
    Cursor mCursor = getContentResolver().query(mImageUri,
      projImage,
      MediaStore.Images.Media.MIME_TYPE + "=? or " + MediaStore.Images.Media.MIME_TYPE + "=?",
      new String[]{"image/jpeg", "image/png"},
      MediaStore.Images.Media.DATE_MODIFIED+" desc");

    if(mCursor!=null){
     while (mCursor.moveToNext()) {
      // 获取图片的路径
      String path = mCursor.getString(mCursor.getColumnIndex(MediaStore.Images.Media.DATA));
      int size = mCursor.getInt(mCursor.getColumnIndex(MediaStore.Images.Media.SIZE))/1024;
      String displayName = mCursor.getString(mCursor.getColumnIndex(MediaStore.Images.Media.DISPLAY_NAME));
      //用于展示相册初始化界面
      mediaBeen.add(new MediaBean(MediaBean.Type.Image,path,size,displayName));
      // 获取该图片的父路径名
      String dirPath = new File(path).getParentFile().getAbsolutePath();
      //存储对应关系
      if (allPhotosTemp.containsKey(dirPath)) {
       List<MediaBean> data = allPhotosTemp.get(dirPath);
       data.add(new MediaBean(MediaBean.Type.Image,path,size,displayName));
       continue;
      } else {
       List<MediaBean> data = new ArrayList<>();
       data.add(new MediaBean(MediaBean.Type.Image,path,size,displayName));
       allPhotosTemp.put(dirPath,data);
      }
     }
     mCursor.close();
    }
    //更新界面
    runOnUiThread(new Runnable() {
     @Override
     public void run() {
      //...
     }
    });
   }
  }).start();
 }

//videoId是这个视频文件在数据库的ID
MediaStore.Video.Thumbnails.getThumbnail(getContentResolver(), videoId, MediaStore.Video.Thumbnails.MICRO_KIND, null);

 /**
  * 获取手机中所有视频的信息
  */
 private void getAllVideoInfos(){
  new Thread(new Runnable() {
   @Override
   public void run() {
    HashMap<String,List<MediaBean>> allPhotosTemp = new HashMap<>();//所有照片
    Uri mImageUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
    String[] proj = { MediaStore.Video.Thumbnails._ID
      , MediaStore.Video.Thumbnails.DATA
      ,MediaStore.Video.Media.DURATION
      ,MediaStore.Video.Media.SIZE
      ,MediaStore.Video.Media.DISPLAY_NAME
      ,MediaStore.Video.Media.DATE_MODIFIED};
    Cursor mCursor = getContentResolver().query(mImageUri,
      proj,
      MediaStore.Video.Media.MIME_TYPE + "=?",
      new String[]{"video/mp4"},
      MediaStore.Video.Media.DATE_MODIFIED+" desc");
    if(mCursor!=null){
     while (mCursor.moveToNext()) {
      // 获取视频的路径
      int videoId = mCursor.getInt(mCursor.getColumnIndex(MediaStore.Video.Media._ID));
      String path = mCursor.getString(mCursor.getColumnIndex(MediaStore.Video.Media.DATA));
      int duration = mCursor.getInt(mCursor.getColumnIndex(MediaStore.Video.Media.DURATION));
      long size = mCursor.getLong(mCursor.getColumnIndex(MediaStore.Video.Media.SIZE))/1024; //单位kb
      if(size<0){
       //某些设备获取size<0，直接计算
       Log.e("dml","this video size < 0 " + path);
       size = new File(path).length()/1024;
      }
      String displayName = mCursor.getString(mCursor.getColumnIndex(MediaStore.Video.Media.DISPLAY_NAME));
      long modifyTime = mCursor.getLong(mCursor.getColumnIndex(MediaStore.Video.Media.DATE_MODIFIED));//暂未用到

      //提前生成缩略图，再获取：http://stackoverflow.com/questions/27903264/how-to-get-the-video-thumbnail-path-and-not-the-bitmap
      MediaStore.Video.Thumbnails.getThumbnail(getContentResolver(), videoId, MediaStore.Video.Thumbnails.MICRO_KIND, null);
      String[] projection = { MediaStore.Video.Thumbnails._ID, MediaStore.Video.Thumbnails.DATA};
      Cursor cursor = getContentResolver().query(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI
        , projection
        , MediaStore.Video.Thumbnails.VIDEO_ID + "=?"
        , new String[]{videoId+""}
        , null);
      String thumbPath = "";
      while (cursor.moveToNext()){
       thumbPath = cursor.getString(cursor.getColumnIndex(MediaStore.Video.Thumbnails.DATA));
      }
      cursor.close();
      // 获取该视频的父路径名
      String dirPath = new File(path).getParentFile().getAbsolutePath();
      //存储对应关系
      if (allPhotosTemp.containsKey(dirPath)) {
       List<MediaBean> data = allPhotosTemp.get(dirPath);
       data.add(new MediaBean(MediaBean.Type.Video,path,thumbPath,duration,size,displayName));
       continue;
      } else {
       List<MediaBean> data = new ArrayList<>();
       data.add(new MediaBean(MediaBean.Type.Video,path,thumbPath,duration,size,displayName));
       allPhotosTemp.put(dirPath,data);
      }
     }
     mCursor.close();
    }
    //更新界面
    runOnUiThread(new Runnable() {
     @Override
     public void run() {
      //...
     }
    });
   }
  }).start();
 }