上传视频 - 获取Null作为路径

Question

我使用以下代码上传视频。我使用以下代码执行此操作，但我将"cursor"变量设为NULL。有人可以告诉我下面代码中的错误或上传视频的任何其他代码段。

private String getPath(Uri uri) {
    String[] projection = { MediaStore.Video.Media.DATA, MediaStore.Video.Media.SIZE, MediaStore.Video.Media.DURATION}; 
    Cursor cursor = getContentResolver().query(uri, projection, null, null, null);
    cursor.moveToFirst(); 
    String filePath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA));
    int fileSize = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE));
    long duration = TimeUnit.MILLISECONDS.toSeconds(cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DURATION)));


    //some extra potentially useful data to help with filtering if necessary
    System.out.println("size: " + fileSize);
    System.out.println("path: " + filePath);
    System.out.println("duration: " + duration);

    return filePath;
}