How to get duration of an video file?

Question

Hi all, I'm a beginner in Android programming.

I have been write an application to list all video file in a folder and display information of all videos in the folder. But when i try to get the video duration it return null and i can't find the way to get it.

Any one can help me?

Below is my code:

Uri uri = Uri.parse("content://media/external/video/media/9");
Cursor cursor = MediaStore.Video.query(res, data.getData(), new String[]{MediaStore.Video.VideoColumns.DURATION});
if(cursor.moveToFirst()) {
    String duration = cursor.getString(0);
    System.out.println("Duration: " + duration);
}