ASデータ受け渡し～Activity間でデータを受け渡す～

今回は問題にはしておらず。コードだけ載せておきます。

MainActivity.java

package com.example.calculation;

import androidx.appcompat.app.AppCompatActivity;

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);

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

    }
}

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"
    tools:context=".MainActivity"
    android:gravity="center_horizontal">

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

    <Button
        android:id="@+id/startBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="始める"
        android:layout_marginTop="160sp"/>

</LinearLayout>

FirstActivity.java

package com.example.calculation;

import static java.lang.Integer.parseInt;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

public class SecondActivity extends AppCompatActivity {

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

        Intent intent = getIntent();
        int sum = intent.getIntExtra("SUM",0);　・・・➁

        TextView secondSum = findViewById(R.id.secondSum);
        secondSum.setText(String.valueOf(sum));

        EditText secondValue = findViewById(R.id.secondValue);

        ImageButton plusSecondBtn = findViewById(R.id.plusSecondBtn);
        plusSecondBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int sum2 = sum + parseInt(secondValue.getText().toString());
                Intent intent = new Intent(SecondActivity.this,ThirdActivity.class);
                intent.putExtra("SUM2",sum2);　・・・➀
                startActivity(intent);
            }
        });

    }
}

activity_first.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"
    tools:context=".FirstActivity"
    android:gravity="center_horizontal">

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

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="値："
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

    <EditText
        android:id="@+id/firstValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

    <ImageButton
        android:id="@+id/plusFirstBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/ic_sharp_add_24"
        android:layout_marginTop="200sp"/>

</LinearLayout>

SecondActivity.java

package com.example.calculation;

import static java.lang.Integer.parseInt;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

public class SecondActivity extends AppCompatActivity {

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

        Intent intent = getIntent();
        int sum = intent.getIntExtra("SUM",0);　・・・➁

        TextView secondSum = findViewById(R.id.secondSum);
        secondSum.setText(String.valueOf(sum));

        EditText secondValue = findViewById(R.id.secondValue);

        ImageButton plusSecondBtn = findViewById(R.id.plusSecondBtn);
        plusSecondBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int sum2 = sum + parseInt(secondValue.getText().toString());
                Intent intent = new Intent(SecondActivity.this,ThirdActivity.class);
                intent.putExtra("SUM2",sum2);　・・・➀
                startActivity(intent);
            }
        });

    }
}

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"
    tools:context=".SecondActivity"
    android:gravity="center_horizontal">

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

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="値："
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

    <EditText
        android:id="@+id/secondValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>
    <ImageButton
        android:id="@+id/plusSecondBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/ic_sharp_add_24"
        android:layout_marginTop="200sp"/>
    <TextView
        android:id="@+id/secondSum"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="200sp"/>
</LinearLayout>

ThirdActivity.java

package com.example.calculation;

import static java.lang.Integer.parseInt;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

public class ThirdActivity extends AppCompatActivity {

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

        Intent intent = getIntent();
        int sum2 = intent.getIntExtra("SUM2",0);

        TextView thirdSum = findViewById(R.id.thirdSum);
        thirdSum.setText(String.valueOf(sum2));

        EditText thirdValue = findViewById(R.id.thirdValue);

        ImageButton plusThirdBtn = findViewById(R.id.plusThirdBtn);
        plusThirdBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int sum3 = sum2 + parseInt(thirdValue.getText().toString());
                Intent intent = new Intent(ThirdActivity.this,LastActivity.class);
                intent.putExtra("SUM3",sum3);・・・➁
                startActivity(intent);
            }
        });
    }
}

activity_third.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"
    tools:context=".ThirdActivity"
    android:gravity="center_horizontal">

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

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="値："
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

    <EditText
        android:id="@+id/thirdValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

    <ImageButton
        android:id="@+id/plusThirdBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/ic_baseline_calculate_24"
        android:layout_marginTop="200sp"/>
    <TextView
        android:id="@+id/thirdSum"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="200sp"/>

</LinearLayout>

LastActivity.java

package com.example.calculation;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class LastActivity extends AppCompatActivity {

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

        Intent intent = getIntent();
        int sum3 = intent.getIntExtra("SUM3",0);　　・・・➁

        TextView lastSum = findViewById(R.id.lastSum);
        lastSum.setText(String.valueOf(sum3));
    }
}

activity_last.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"
    tools:context=".LastActivity"
    android:gravity="center_horizontal">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="合計："
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

    <TextView
        android:id="@+id/lastSum"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:layout_marginTop="160sp"/>

</LinearLayout>

Intentクラスをインスタンス化し、そのオブジェクトのputInt( )メソッドなどを使用し、データを送る。この場合、タグをつけて渡すことで、受け取り側はそのタグにアクセスすることでデータを受け取ることができます。➀が渡す方で、➁が受け取る方の記述です。