Multiple selectionArgs - 查询 mediaStore

Question

我正在尝试显示特定文件夹中的音频文件。文件夹由用户选择并添加到arraylist，因此arraylist 是动态的。现在，当我查询多个文件夹时， mediaStore 不会返回任何结果。我认为问题出在我的selection 上。我知道selectionArgs 中的项目数应该与选择中的? 匹配，所以我创建了一个可以做到这一点的函数，但没有运气。希望你们能帮助我。谢谢！

下面是代码：

    String[] whereVal;
    String selection;

 Uri uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;



        String[] folderPaths = storage.loadFolderPaths().toArray(new String[storage.loadFolderPaths().size()]);
        selection = MediaStore.Audio.Media.DATA +" IN (" + makePlaceholders(folderPaths.length) + ")" ;
        whereVal = folderPaths;


   String[] projection = {MediaStore.Audio.Media._ID,
            MediaStore.Audio.Media.TITLE,
            MediaStore.Audio.Media.ARTIST,
            MediaStore.Audio.Media.DURATION,
            MediaStore.Audio.Media.DATA,
            MediaStore.Audio.Media.ALBUM_ID};
    Cursor cursor = getActivity().getContentResolver().query(uri, projection, selection, whereVal, null);



private String makePlaceholders(int len) {

    StringBuilder sb = new StringBuilder(len * 2 - 1);
    sb.append("?");
    for (int i = 1; i < len; i++)
        sb.append(",?");
    Log.e("len: ", String.valueOf(len));
    Log.e("Selection: ",sb.toString());
    return sb.toString();

}

Answer 1

除了我的评论：

            // strip trackname
    path = path.substring(path.lastIndexOf("/")+1,path.length());
    String where = MediaStore.Audio.Media.DATA + " LIKE " + "\'%" +path+"%\'";