SectionedAdapter | fast implementation of list adapter | File Utils library

I am making a music player. so in album section, I try to load an image of an album by the Picasso library. images are loaded correctly but when I scroll then app lagging problem occur. I also try with glide but no improvement in performance.I think that this problem occurs due to image load from this link " content://media/external/audio/albumart ". is there any alternative method if not then how to improve scrolling performance..??

I have used rxjava and retrofit to load data from backend and update the UI. But there is no data displayed on section view. I have tested it, and the backend data load successful and the UI can be updated using fake data.

Are there something wrong when I use Rxjava?

I was trying to trying accomplish something like this:

Required:

1.I want to Make a Sectioned Header Listview in Android.

2.That should be Swipe to delete a item, with Undo option like Gmail App.but Gmail App not contains Section Header.

3.My Application should be have Section Header.

i tried below mentioned link for Swipe to delete along with Undo button. its worked perfectly.

Problem:

EDIT :1(ListView)

1.i found the code for Swipe to Delete a item with Undo in Listview Link-Swipe to delete a listview item and Section Header Using Listview link-Section header in listview.

2.both are having two different Base Adapters Iam getting some Error,Please help me to merge that adapters or suggest me any new way to add section Header in Swipe to Delete a Listview items.

CODE: Class for Swipe to Delete and Section Header in Listview

ListViewActivity.class