How to pass values between Fragments in Android?

This example demonstrates how do I pass values between fragments 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.

<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:background="#574706"
   tools:context=".MainActivity">
   <fragment
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:name="app.com.sample.FragmentOne"
      android:id="@+id/fragment"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      tools:layout="@layout/fragment_fragment_one" />
   <fragment
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:name="app.com.sample.FragmentTwo"
      android:id="@+id/fragment2"
      android:layout_below="@+id/fragment"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="41dp"
      tools:layout="@layout/fragment_fragment_two" />
</RelativeLayout>

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

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity implements FragmentOne.OnFragmentInteractionListener{
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      getMenuInflater().inflate(R.menu.menu_main, menu);
      return true;
   }
   @Override
   public boolean onOptionsItemSelected(MenuItem item) {
      int id = item.getItemId();
      if (id == R.id.textUpdate) {
         return true;
      }
      return super.onOptionsItemSelected(item);
   }
   @Override
   public void onFragmentInteraction(String userContent) {
      FragmentTwo fragmentTwo =
         (FragmentTwo)
         getSupportFragmentManager().findFragmentById(R.id.fragment2);
      fragmentTwo.updateTextField(userContent);
   }
}

Step 4 − Create two fragments (FragmentOne and FragmentTwo) and add the following code −

a) FragmentOne.java

import android.app.Activity;
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.Button;
import android.widget.EditText;
import android.widget.Toast;
public class FragmentOne extends Fragment {
   private OnFragmentInteractionListener mListener;
   private EditText userInput;
   private String userData;
   public FragmentOne() {
   }
   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
      View view = inflater.inflate(R.layout.fragment_fragment_one, container, false);
      userInput = view.findViewById(R.id.userInput);
      Button update = view.findViewById(R.id.button);
      update.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            if(userInput.getText().toString().equals("")){
               Toast.makeText(getActivity(), "User input value must be filled",
               Toast.LENGTH_LONG).show();
               return;
            }
            userData = userInput.getText().toString();
            onButtonPressed(userData);
         }
      });
      return view;
   }
   public void onButtonPressed(String userContent) {
      if (mListener != null) {
         mListener.onFragmentInteraction(userContent);
      }
   }
   @Override
   public void onAttach(Activity activity) {
      super.onAttach(activity);
      try {
         mListener = (OnFragmentInteractionListener) activity;
      } catch (ClassCastException e) {
         throw new ClassCastException(activity.toString() + " must implement
         OnFragmentInteractionListener");
      }
   }
   @Override
   public void onDetach() {
      super.onDetach();
      mListener = null;
   }
   public interface OnFragmentInteractionListener {
      void onFragmentInteraction(String userContent);
   }
}

fragment_fragment_one.xml −

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:padding="4dp"
   android:paddingBottom="32dp">
   <EditText
      android:id="@+id/userInput"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="16dp"
      android:ems="10"
      android:inputType="text">
      <requestFocus />
   </EditText>
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_below="@id/userInput"
      android:layout_marginTop="20dp"
      android:padding="16dp"
      android:elevation="4dp"
      android:text="Update" />
</RelativeLayout>

b) FragmentTwo.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 FragmentTwo extends Fragment {
   private TextView updateText;
   public FragmentTwo() {
   }
   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
      View view =
      inflater.inflate(R.layout.fragment_fragment_two, container, false);
      updateText = view.findViewById(R.id.textUpdate);
      return view;
   }
   public void updateTextField(String newText){
      updateText.setText(newText);
   }
}

fragment_fragment_two −

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent">
   <TextView
      android:id="@+id/textUpdate"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text=""
      android:textSize="24sp"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:textStyle="bold"
      android:layout_marginTop="32dp" />
</RelativeLayout>

Step 5 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest
   xmlns:android="http://schemas.android.com/apk/res/android"
   package="app.com.sample">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action
               android:name="android.intent.action.MAIN" />
            <category
               android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

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 −