Android : Play video while downloading in android

this functionality seems to be a bit common to most android players but how do you actually implement this. say you have an http link to the mp4 file you want to play. how do you implement it in android? have read the following SO posts here and here but i have no idea what it means or how to implement it. So far what i did was just this.

Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse(fileUrl), "video/*");
startActivity(intent);

thanks and good day!!