How to check if the fragment exists

Question

I am trying to talk to the fragments from activity.

Here in my MainActivity I am adding multiple fragments ok so for fine.

My main requirement is I don't want to add if fragment is already added.

So how can we check this condition?

Please help me some one.

code:-

 private void intializingFragments(Fragment fragment) {

        FragmentManager fragmentManager = getSupportFragmentManager();

        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.fragment_container, fragment);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.commit();
    }

    private View.OnClickListener intialization() {

        return new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                int getId = v.getId();

                if (getId == R.id.first) {
                    intializingFragments(new Fragment1());

                } else if (getId == R.id.second) {
                    intializingFragments(new Fragment2());

                } else if (getId == R.id.third) {
                    intializingFragments(new Fragment3());
                } 
            }
        };
    }

Answer 1

You can use findFragmentByTag() or findFragmentById() functions to get a fragment. If mentioned methods are returning null then that fragment does not exist.

Fragment fragmentA = fragmentManager.findFragmentByTag("frag1");
if (fragmentA == null) {
  // not exist
} else {
  // fragment exist
}

for example:- http://wiki.workassis.com/android-load-two-fragments-in-one-framelayout/

Answer 2

You may find fragment in fragmentmanager:

List<Fragment> frags = getSupportFragmentManager().getFragments();
for (Fragment f : frags) { 
  <find what you want>... 
}

Or you may add fragment with tag:

getSupportFragmentManager()
  .beginTransaction()
  .add(R.id.frame, new MyFragment(), "frag1")
  .commit();

And find by tag

getSupportFragmentManager().findFragmentByTag("frag1");

Answer 3

FragmentManager fragmentManager = getSupportFragmentManager();
     FragmentTransaction transaction = fragmentManager.beginTransaction();
                Fragment topFragment = fragmentManager.findFragmentById(R.id.container);
                FragmentA fragmentA = new FragmentA();
                if(topFragment!= null)
                {
                    transaction.remove(topFragment);
                    transaction.add(R.id.container, fragmentA, "FA");
                    transaction.commit();
                }
                else
                {
                    transaction.add(R.id.container, fragmentA, "FA");
                    transaction.commit();
                }

try this

private void intializingFragments(Fragment fragment) {
      FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        Fragment topFragment = fragmentManager.findFragmentById(R.id.container);
        if(topFragment!= null)
        {
            fragmentTransaction.remove(topFragment);
            fragmentTransaction.add(R.id.fragment_container, fragment);
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();
        }
        else
        {
            fragmentTransaction.add(R.id.fragment_container, fragment);
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();
        }

    }

Answer 4

How to check whether a fragment exists, without knowing its resource ID or tag:

// MyActivity.kt
val exists: Boolean = supportFragmentManager
    .fragments
    .filterIsInstance<MyFragment>()
    .isNotEmpty()

Answer 5

There are many ways by which you can track the last added fragment. The simplest one is by finding the tag within fragment manager. Here is the sample code of it:

public boolean isFragmentPresent(String tag) {
    Fragment frag = getSupportFragmentManager().findFragmentByTag(tag);
    if (frag instanceof HomeFragment) {
        return true;
    } else
        return false;
}

Alternatively, you can use your own variable to check whether the last added fragment is the same as the current fragment. Here is the sample code for it:

public boolean isCurrentFragment(Fragment fragment) {
    if (fragment instanceof HomeFragment && getLastAddedFragment() instanceof HomeFragment) { // getLastAddedFragment() is a method which return the last added fragment instance
        return true;
    } else
        return false;
}

And you can use it like:

if (isCurrentFragment(new HomeFragment())) {
    // Last added Fragment is the HomeFragment
}

Answer 6

You can go for popBackStack Pop the last fragment transition from the manager's fragment back stack. If there is nothing to pop, false is returned. enter link description here