How to pass a variable from Activity to Fragment in Android?

This example demonstrates how do I pass a variable from activity to Fragment in android.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

Step 3 − Add the following code to src/MainActivity.java

import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
   EditText editText;
   Button button;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      FragmentManager fragmentManager = getSupportFragmentManager();
      final FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
      final MyFragment myFragment = new MyFragment();
      button = findViewById(R.id.btnSendData);
      editText = findViewById(R.id.editText);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            Bundle b = new Bundle();
            b.putString("message", editText.getText().toString());
            myFragment.setArguments(b);
            fragmentTransaction.add(R.id.frameLayout, myFragment).commit();
         }
      });
   }
}

Step 4 – Create a new fragment activity and add the following code −

MyFragment.java −

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MyFragment extends Fragment {
   TextView textView;
   public MyFragment() {
   }
   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
      View view = inflater.inflate(R.layout.fragment_my, container, false);
      textView = view.findViewById(R.id.textView);
      Bundle bundle = getArguments();
      String message = bundle.getString("message");
      textView.setText(message);
      return view;
   }
}

fragment_my.xml −

Step 5 - Add the following code to androidManifest.xml

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –

Click here to download the project code.