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();