Set selection method is not working in gallery in android

wish help you to fix your issue I ended up using this as a guide. I didn't get exactly what I wanted, but this was useful.

it fixes the issue I really need horizontal scrolling in my app, so I overrode Gallery and I'm trying to do something with an OnItemSelectedListener, and a GestureDetector I'm calling from an OnTouchListener I've set on the Gallery. What I want is to remove the auto-selection of Gallery items as I scroll, but I want to be able to click an item to select it. , To remove selection from all items you should do this:

youGallery.setUnselectedAlpha(1);

Hope that helps A Uri value does not have to point to a local file resource that you can read. There are various possible Uri schemes, including all the standard Internet ones (e.g., http). From the standpoint of content pickers, you will mostly get back file:// and content:// schemes, and a lot more of the latter over time.
A Uri with a content:// scheme that points to a stream behaves much like a Uri with an http:// scheme. Neither necessarily point to some local file. Instead, you consume the stream itself (openInputStream() on a ContentResolver for content://, something like HttpUrlConnection for http://), obtain the MIME type independently (getType() on a ContentResolver for content://, get it from HTTP headers for http://), and cook up your own concept for a filename, as there may not be one readily derivable from the Uri itself.

To fix this issue Unfortunately, as stated by http://developer.android.com/reference/android/content/Intent.html#EXTRA_ALLOW_MULTIPLE, this is not possible.

To fix the issue you can do When action is cancelled then data will be null(returned by the gallery app) but Kotlin doesn't allow null by default so hence the issue.
To avoid that, set data as nullable using ? as Intent?

public override fun onActivityResult(requestCode: Int,
               resultCode: Int,
               data: Intent?) {
// mark as null type       ^