Check fragment for exclude show same fragment again

Question

I use this code to check a fragment before showing it. What can you say about it?

int backStackEntryCount = getFragmentManager().getBackStackEntryCount();
if (backStackEntryCount > 0){
    String newFragmentTag = fragment.getClass().getSimpleName()+"|"+fragment.getArguments();
    String nowShowFragmentTag = getFragmentManager().findFragmentById(R.id.main_activity_fragment_container).getTag();
    if (!newFragmentTag.equals(nowShowFragmentTag)) {
        getFragmentManager()
                .beginTransaction()
                .replace(R.id.main_activity_fragment_container, fragment, fragment.getClass().getSimpleName()+"|"+fragment.getArguments())
                .addToBackStack(fragment.toString())
                .commit();
    }
}

Answer 1

• In this line:

  .replace(R.id.main_activity_fragment_container, fragment, fragment.getClass().getSimpleName()+"|"+fragment.getArguments())
  

  you can reuse the newFragmentTag variable:

  .replace(R.id.main_activity_fragment_container, fragment, newFragmentTag)
  

  This way you don't have to perform the same string concatenation twice, which is sort of the purpose of variables & methods in the first place.

• Try to use getSupportFragmentManager() if you're using AppCompatActivity.

• Since you're going to replace the fragment in R.id.main_activity_fragment_container anyways, there's no need to check the back stack. Just check if there are any fragments in the container before checking its tag.

---

Below is how I would rewrite the code in my style (you don't have to follow this):

FragmentManager fManager = getSupportFragmentManager();
String newFragmentTag = fragment.getClass().getSimpleName() + "  |  " + fragment.getArguments();

Fragment currentFragment = fManager.findFragmentById(R.id.main_activity_fragment_container);
if (currentFragment != null && currentFragment.getTag().equals(newFragmentTag)) {
    Log.w(TAG, "Fragment is already displayed");
    return;
}

fManager
    .beginTransaction()
    .replace(R.id.main_activity_fragment_container, fragment, newFragmentTag)
    .addToBackStack(fragment.toString())
    .commit();