CODEWITHSUNDEEP
androidandroid-fragments
xiimoss
xiimoss

Reputation: 805

Check which Activity loads a fragment

Is there a way to check which activity loads a fragment from within the fragment? I have a user profile fragment which is loaded from 2 different activities but only one passes a value in, so when getting values from the bundle when the fragment loads from the activity that doesn't pass a value throws a nullpointerexception. Or is there a better way to pass the value into the fragment so the fragment can get the value only when loaded from this specific activity?

Upvotes: 0

Views: 3786

Answers (2)

savepopulation
savepopulation

Reputation: 11921

You can define two static methods (also known as Static Factory Methods) which returns instances of your Fragment with the parameters you want to pass with bundle like the following code:

private static final String BUNDLE_VALUE_KEY = "value";

@NonNull
public static YourFragment newInstance() {
   return new YourFragment();
}

@NonNull
public static YourFragment newInstance(@NonNull String yourValue) {
   final YourFragment instance = new YourFragment();
   final Bundle args = new Bundle();
   args.putString(BUNDLE_VALUE_KEY,yourValue);
   instance.setArguments(args);
   return instance;
}

In your Activity which you want to pass the value you can use:

final YourFragment fragment = YourFragment.newInstance(value);
getSupportFragmentManager().beginTransaction()
          .replace(R.id.framelayout, fragment)
          .commit();

In other Activity you can use:

final YourFragment fragment = YourFragment.newInstance();
getSupportFragmentManager().beginTransaction()
        .replace(R.id.framelayout, fragment)
        .commit();

And in onCreate method of your Fragment you can check arguments and init your value like the following code:

final Bundle args = getArguments();
if(args != null){
      yourValue = args.getString(BUNDLE_VALUE_KEY,null);
}

So if your Fragment is attached to the Activity which passes data you'll have it. If the Fragment is attached to other Activity you'll have the initial value (in the example it's null)

Or you can check the instance of Activity which Fragment gets attached. (Not best practice)

if(getActivity() instanceof YourActivityWhichPassesData){
   yourValue = getArguments().getString(BUNDLE_VALUE_KEY,null);
}

Upvotes: 1

stamanuel
stamanuel

Reputation: 3819

You can simply do this check in your fragment:

if(getActivity() instanceof SomeActivity){
//do something
}

You can also cast the getActivity() call if you are sure which Activity it is (and then call methods from that Activity).

Upvotes: 6

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