java - How to set layout dynamically in android

Question

Well, Suppose there is an Activity called MainActivity and there are two layouts called layout1 and layout2 both have few buttons. By default MainActivity layout is layout1 like following:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout1);

Now what I did actually is by clicking a button in layout1 the second layout is set like following:

    someBtn1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            setContentView(R.layout.layout2);
        }
    });

There are another button in layout2 to return back to layout1 like following:

    someBtn2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            setContentView(R.layout.layout1);
        }
    });

Problem is when I returned back to layout1 then OnClickListener of someBtn1 is not working. It seems I need to set OnClickListener again for someBtn1 of layout1. How I can write code to make them work perfectly with best practices ?

Answer 1

The best practice is to use fragments instead of change the content view.

In your code, setContentView with layouts recreate (inflate) all your views every time, so the call setContentView(R.layout.layout1) in someBtn2 click listener will create a new button without the associated listener.

If you don't want to use fragments you can do this:

private View view1, view2;

public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  view1 = getLayoutInflater().inflate(R.layout.layout1, null);
  view2 = getLayoutInflater().inflate(R.layout.layout2, null);
  setContentView(view1);

The listeners will be:

someBtn1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        setContentView(view2);
    }
});


someBtn2.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        setContentView(view1);
    }
});