how to add button click event in android studio

Question

So I have done some research, and after defining you button as an object by the code

private Button buttonname;
buttonname = (Button) findViewById(R.id.butto         


        

Answer 1

in Activity java class you would need a method first to find the view of the button as :

btnSum =(Button)findViewById(R.id.button);

after this set on click listener

btnSum.setOnClickListener(new View.OnClickListener() {

and override onClick method for your functionality .I have found a fully working example here : http://javainhouse.blogspot.in/2016/01/button-example-android-studio.html