Unable to pass data from Activity to fragment

Question

I am new to android. I want to pass data from activity to fragment. I saw several questions and they suggested me one solution. The Solution is passing data via bundle. I tried that solution from stack overflow. But doesn't help me to fix this. It shows Null pointer Exception. The weird thing is every answer has this comment that states null pointer exception error with lots of upvotes. Then what is the correct way to pass data from activity to fragment

Here's the Activity Code:
I have used Bottom Navigation Bar with 2 fragments

private BottomNavigationView.OnNavigationItemSelectedListener navigationItemSelectedListener=new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            Fragment selectedFragment=null;

            switch (item.getItemId())
            {
                case R.id.home_tab:

                    selectedFragment =new home_fragment();
                    Log.w("SelecetedFra", "Selfragloaded");
                    Bundle bundle = new Bundle();
                    bundle.putString("board_name", "cbse");
                    bundle.putString("class_name", "12th");
             
                    selectedFragment.setArguments(bundle);
                    break;
                case R.id.analytics_tab:
                    selectedFragment =new analytics_fragment();
                    break;
               
            }
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,selectedFragment).commit();
            return true;
        }
    };

Fragment Code:

public class home_fragment extends Fragment {

    private ViewGroup placeholder;
    String board_name;
    String class_name;
    private View view;

    public home_fragment() {
    }
    // TODO: Rename and change types and number of parameters
    public static home_fragment newInstance(String param1, String param2) {
        home_fragment fragment = new home_fragment();
        
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // In here, I am getting the data
        Bundle bundle = this.getArguments();
        Log.w("bundle ", String.valueOf(bundle));

        board_name = getArguments().getString("board_name");
        class_name = getArguments().getString("class_name");
     

        Log.w("homeFragBundle",class_name+""+board_name);

        
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        view=inflater.inflate(R.layout.fragment_home_fragment_loader, container, false);
        placeholder = (ViewGroup) view;
        return placeholder;
    }

}

Error I Got:

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.Bundle.getString(java.lang.String)' on a null object reference

I don't know how to pass data. Everyone suggests me to pass data via bundle. But it gives me null pointer exception. Please help me with some solutions.

@a_local_nobody Its a default one generated when creating a fragment — rovij, Mar 05 '21 at 11:59
so then delete it, don't keep it there, just leaves room for bugs or issues — a_local_nobody, Mar 05 '21 at 12:01
cool, just making sure you don't cause bugs by accident, can't really see why your code wouldn't work — a_local_nobody, Mar 05 '21 at 12:04

score 0 · Answer 1 · edited Mar 05 '21 at 11:53

0

I think the answer I gave to someone else in the following post:

Share data in fragments

Can be applied to your case too. The ViewModel paradigm is slick and efficient. Try it to exchange data between activity and fragments but also fragments with other fragments.

edited Mar 05 '21 at 11:53

a_local_nobody

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answered Mar 05 '21 at 11:47

Sergiob

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score 0 · Accepted Answer · answered Mar 05 '21 at 12:46

I also experienced this type of issue in one of my projects. I used another way to pass the Data from activity to fragment without using bundle.

Assign the bundle values to variables in Activity and make it public.

public String board_name = "cbse"
public String class_name = "12th"

Now on the fragment side,

Call the Variable like this below and assign it to a String in the fragment

YourActivityName myActivity = (YourActivityName) getActivity();
board_name = myActivity.board_name;
class_name = myActivity.class_name;

Now you can get the values and use them for further process in the fragment.

Unable to pass data from Activity to fragment

2 Answers2