http://stackoverflow.com/questions/1740654/view-image-in-action-view-intent
Intent intent = new Intent();
intent.setAction(android.content.Intent.ACTION_VIEW);
File file = new File("/sdcard/test.mp4");
intent.setDataAndType(Uri.fromFile(file), "video/*");
startActivity(intent);
Intent intent = new Intent();
intent.setAction(android.content.Intent.ACTION_VIEW);
File file = new File("/sdcard/test.mp3");
intent.setDataAndType(Uri.fromFile(file), "audio/*");
startActivity(intent);