What do you mean that buttons for day, week,year? Combine built-in date slicer and Timeline custom visual and check if you get expected result.
This combination doesn't work for me.
I wanted to use slicer to select current day, last week, last month or last year, and have buttons as control.
I started writing custom slicer, however I've got some problems, even though I used selection manager and iselectionid field in data, it doesn't work with dates. I implemented same technique to filter names and it worked, but not with date. What can be the problem?
Could you please post a screenshot about your desired slicer? And could you please post a screenshot about your current problem?