[안드로이드]프래그먼트(Fragment) 간의 데이터 전달방법(Listener)

2021/01/07 - [안드로이드] - [안드로이드] 다이얼로그(Dialog) 사용자정의 (Custom) 화면으로 보여주기

2021/01/06 - [안드로이드] - [안드로이드]다이얼로그(Dialog) 체크박스(CheckBox)로 보여주기

2021/01/05 - [안드로이드] - [안드로이드] 다이얼로그(Dialog) 리스트(List)로 보여주는 방법

이번 시간에는 프래그먼트 간의 데이터 전달하는 간단한 예제를 만들어 보겠습니다. 

1. 프래그먼트 생성

프래그먼트는 2개 생성하며, 이름은 FragmentA, FragmentB로 하겠습니다.

자동으로 [FragmentA.java, fragment_a.xml], [FragmentB.java, fragment_b.xml] 이 생성됩니다.

Fragment_a.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/holo_green_light"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    android:padding="16dp"
    tools:context=".FragmentA">

    <EditText
        android:id="@+id/edit_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/btn_ok"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="OK" />

</LinearLayout>

Fragment_b.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:context=".FragmentB"
    android:background="@android:color/holo_blue_light"
    android:padding="16dp"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    >

    <EditText
        android:id="@+id/edit_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/btn_ok"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="OK"/>

</LinearLayout>

FragmentA.java

package com.kwon.toast;

import android.content.Context;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;


public class FragmentA extends Fragment {

    private EditText editText;
    private Button btnOk;
    private FragmentAListener listener;

    public interface FragmentAListener{
        void onInputASent(CharSequence input);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View v =  inflater.inflate(R.layout.fragment_a, container, false);

        editText = v.findViewById(R.id.edit_text);
        btnOk = v.findViewById(R.id.btn_ok);
        btnOk.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                CharSequence input = editText.getText().toString();
                listener.onInputASent(input);
            }
        });

        return v;
    }

    public void updateEditText(CharSequence newText){
        editText.setText(newText);
    }

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        if(context instanceof FragmentAListener){
            listener = (FragmentAListener)context;
        }else{
            throw new RuntimeException(context.toString() + " must implement FragmentListner");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        listener = null;
    }
}

FragmentB.java

package com.kwon.toast;

import android.content.Context;
import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;


public class FragmentB extends Fragment {

    private EditText editText;
    private Button btnOk;
    private FragmentBListener listener;

    public interface FragmentBListener{
        void onInputBSent(CharSequence input);
    }

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

        editText = v.findViewById(R.id.edit_text);
        btnOk = v.findViewById(R.id.btn_ok);
        btnOk.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                CharSequence input = editText.getText().toString();
                listener.onInputBSent(input);
            }
        });

        return v;
    }

    public void updateEditText(CharSequence newText){
        editText.setText(newText);
    }

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        if(context instanceof FragmentBListener){
            listener = (FragmentBListener)context;
        }else{
            throw new RuntimeException(context.toString() + " must implement FragmentListner");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        listener = null;
    }
}

2. 메인화면 구현(activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rootLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">


    <FrameLayout
        android:id="@+id/container_a"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <FrameLayout
        android:id="@+id/container_b"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

3. 메인코드 구현(MainActivity.java)

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;


public class MainActivity extends AppCompatActivity implements  FragmentA.FragmentAListener, FragmentB.FragmentBListener{

    private FragmentA fragmentA;
    private FragmentB fragmentB;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        fragmentA = new FragmentA();
        fragmentB = new FragmentB();

        getSupportFragmentManager().beginTransaction()
                .replace(R.id.container_a, fragmentA)
                .replace(R.id.container_b, fragmentB)
                .commit();
    }


    @Override
    public void onInputASent(CharSequence input) {
        fragmentB.updateEditText(input);
    }

    @Override
    public void onInputBSent(CharSequence input) {
        fragmentA.updateEditText(input);
    }
}

4. 실행화면

2021/01/07 - [안드로이드] - [안드로이드] 다이얼로그(Dialog) 사용자정의 (Custom) 화면으로 보여주기

2021/01/06 - [안드로이드] - [안드로이드]다이얼로그(Dialog) 체크박스(CheckBox)로 보여주기

2021/01/05 - [안드로이드] - [안드로이드] 다이얼로그(Dialog) 리스트(List)로 보여주는 방법