How to make a fragment be in the exact same way I left it when I return to it from another fragment?

Question

I have a few fragments in my app, but my code opens a new fragment every time I click the button.

I want to know how can I change this, and make the fragment return to the exact same state I left it in.

The code im using right now:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragments);

        MainActivity fragment = new MainActivity();
        FragmentTransaction transaction = getSupportFragmentManager()
                .beginTransaction();
        transaction.add(R.id.fragment_place, fragment);
        transaction.commit();

        turnGPSOn();
    }

    public void onSelectFragment(View view) {

        if (view == findViewById(R.id.add)) 
        {
            newFragment = new Add();
        }
        else if (view == findViewById(R.id.map)) 
        {
            newFragment = new MainActivity();
        } 
        else 
        {
            newFragment = new Add();
        }

        FragmentTransaction transaction = getSupportFragmentManager()
                .beginTransaction();
        transaction.replace(R.id.fragment_place, newFragment);
        transaction.addToBackStack(null);
        transaction.commit();
    }

Thanks!

Answer 1

You are getting a new fragment each time because you are calling to new XXX() each time.

I think you could use findFragmentByTag in order to solve this problem. As you can see here the replace function can accept a third parameter that is a String, this String can be used as an id to identify different fragments you have used previously.

So to sum up you can:

1. Call Fragment f = getSupportFragmentManager().findFragmentByTag("FragAdd"); for example in order to retrieve the first fragment.

2. If f is null, that means that you haven't used that fragment yet, so you have to call to new Add() if not, use that fragment to replace the old one. For example like this:

FragmentTransaction transaction = getSupportFragmentManager()
            .beginTransaction();

transaction.replace(R.id.fragment_place, newFragment, "FragAdd"); //or whatever other string you want to use
transaction.addToBackStack(null);
transaction.commit();

Hope it helps :)