I have a contact app based on SharePoint Contact list. On my screen I am wanting a side slider (or gallery) of the alphabet to allow the Main galley to be filtered by first letter of Full Name. I want to make it like the contact list on your phone.
This is my screen: ( currently using a Side Gallery but would like to use slider but cannot figure out how to use slider instead of gallery of Alphabet.)

On Visable property:
Create collection for gallery or slider: ClearCollect(ContactOrder, {Letter:"A", Number:1}, {Letter:"B", Number:2}, {Letter:"C", Number:3},{Letter:"D", Number:4}, {Letter:"E", Number:5},{Letter:"F", Number:6},{Letter:"G", Number:7},{Letter:"H", Number:8},{Letter:"I", Number:9},{Letter:"J", Number:10},{Letter:"K", Number:11},{Letter:"L", Number:12},{Letter:"M", Number:13},{Letter:"N", Number:14},{Letter:"0", Number:15},{Letter:"P", Number:16},{Letter:"Q", Number:17},{Letter:"R", Number:18},{Letter:"S", Number:19},{Letter:"T", Number:20},{Letter:"U", Number:21},{Letter:"V", Number:22},{Letter:"W", Number:23},{Letter:"X", Number:24},{Letter:"Y", Number:25},{Letter:"Z", Number:26})
Side Gallery (Currently):
Items:
ContactOrder
OnSelect:
Set(SearchLetter,ThisItem.Letter)
Main Gallery (Currently):
Items:
Filter('SharePoint Contact List',StartsWith('Full Name',SearchLetter))
{'Full Name' is a text field}
Issues/Questions:
If stay with the gallery:
1. If no Letter is selected nothing shows, It needs to see to show all items in list on start and have a button/letter that can reset the Main gallery back to show all.
Or
To get slider working.
1. I would like it to be on a slider to make for easier use on phone but I would need the slider to display the letter instead of the number.
Any idea's on how to fix these?