AS中級 フラグメント編③～Fragmentの真骨頂、同じフラグメントを異なるアクティビティに配置する～

MainActivity.java

package com.example.realfragmentdemo;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

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

        TopFragment topFragment = TopFragment.newInstance();
        MiddleFragment middleFragment = new MiddleFragment();

        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.container1_1,topFragment);
        fragmentTransaction.add(R.id.container1_2,middleFragment);
        fragmentTransaction.commit();

        Button nextBtn = findViewById(R.id.nextBtn);
        nextBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this,SecondActivity.class));
            }
        });


    }
}

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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/container1_1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"/>
    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/container1_2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"/>
    <Button
        android:id="@+id/nextBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="次ページへ"/>

</LinearLayout>

SecondActivity.java

package com.example.realfragmentdemo;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.os.Bundle;

public class SecondActivity extends AppCompatActivity {

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

        MiddleFragment middleFragment = MiddleFragment.newInstance();
        BottomFragment bottomFragment = BottomFragment.newInstance();

        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.container2_1,middleFragment);
        fragmentTransaction.add(R.id.container2_2,bottomFragment);
        fragmentTransaction.commit();

    }
}

activity_second.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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".SecondActivity">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/container2_1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"/>
    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/container2_2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"/>

</LinearLayout>

TopFragment.java

package com.example.realfragmentdemo;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

public class TopFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        return inflater.inflate(R.layout.fragment_top, container, false);
    }

    public static TopFragment newInstance(){
        TopFragment topFragment = new TopFragment();
        return topFragment;
    }
}

fragment_top.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FF0000"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".TopFragment">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello"/>

</LinearLayout>

MiddleFragment.java

package com.example.realfragmentdemo;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

public class MiddleFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        return inflater.inflate(R.layout.fragment_middle, container, false);
    }

    public static MiddleFragment newInstance(){
        MiddleFragment middleFragment = new MiddleFragment();
        return middleFragment;
    }
}

fragment_middle.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FF00FF"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".MiddleFragment">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="Hi"/>

</LinearLayout>

BottomFragment.java

package com.example.realfragmentdemo;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

public class BottomFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        return inflater.inflate(R.layout.fragment_bottom, container, false);
    }

    public static BottomFragment newInstance(){
        BottomFragment bottomFragment = new BottomFragment();
        return bottomFragment;
    }
}

fragment_botton.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#00FF00"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".BottomFragment">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="Bye"/>

</LinearLayout>