How Can I Implement a Listener Interface in Two Different classes in Android?

Question

I can't figure out how to connect a listener to a separate class called by an activity.

I have My activity, which loads a tabbed view of Fragments. Each Fragment loads its own recycler view

Activity ---> ViewPager(Tabs) ----> Fragments ---> RecyclerView//(This is where I want the listener)
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Background Handler for calling a web server periodically //(I want this to call the listener).

In my mind the RecyclerView and the Handler are different.

I only know how to implement a listener in the class that creates the caller.

How can I add a listener to a class that is not connected to the caller?

@grolschie in that example the MyActivity Class calls the MyButton Class and listens to it. My Fragment has nothing to do with the Handler but I want it to listen to it. — silversunhunter, Oct 09 '19 at 04:22

score 0 · Answer 1 · answered Oct 09 '19 at 05:41

the question was a little confusing but i hope this solution help in kotlin:

define a kotlin callback in recyclerView adapter and call it for example on click
define a kotlin callback in viewPager and implement in in Activity
implement RVAdapter call back in viewpager fragment create method which job is to invoke activity callback
in activity when you impl view pager adapter callback you can call your handler

if you'r code is in java you can use abstract classes.

How Can I Implement a Listener Interface in Two Different classes in Android?

1 Answers1