java - 最初のアクティビティの値を保持し、2 番目のアクティビティから最初のアクティビティに戻ったときにそれらを確認する方法

Question

最初のアクティビティで、テキスト ボックスにテキストを入力しました。

次に、「SAVE」ボタンを押すと、2 番目のアクティビティに移動します。

ここで、「戻る」ボタンを押すと、以前に入力した値/テキストが表示されない最初のアクティビティに戻ります。

共有設定も使用してみました。

これが私のコードです

MainActivity.java

package com.example.madhur.intentclear;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
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 {

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

        final EditText tv1 = findViewById(R.id.editText);
        final EditText tv2 = findViewById(R.id.editText2);
        final EditText tv3 = findViewById(R.id.editText3);
        final Button bt1 = findViewById(R.id.button);
        bt1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {

                SharedPreferences sharedPreferences1=getSharedPreferences("value1",Context.MODE_PRIVATE);
                SharedPreferences.Editor editor=sharedPreferences1.edit();
                editor.putString("tv1",tv1.getText().toString());

                SharedPreferences sharedPreferences2=getSharedPreferences("value2",Context.MODE_PRIVATE);
                SharedPreferences.Editor editor2=sharedPreferences2.edit();
                editor2.putString("tv2",tv2.getText().toString());

                SharedPreferences sharedPreferences3=getSharedPreferences("value3",Context.MODE_PRIVATE);
                SharedPreferences.Editor editor3=sharedPreferences3.edit();
                editor3.putString("tv3",tv3.getText().toString());

                editor.apply();
                editor2.apply();
                editor3.apply();
               tv1.setText(String.valueOf(sharedPreferences1.getString("tv1",null)));
               tv2.setText(String.valueOf(sharedPreferences2.getString("tv2",null)));
               tv3.setText(String.valueOf(sharedPreferences3.getString("tv3",null)));

                Intent intent = new Intent(MainActivity.this, Main2Activity.class);
                intent.putExtra("tv1",tv1.getText().toString());
                intent.putExtra("tv2",tv2.getText().toString());
                intent.putExtra("tv3",tv3.getText().toString());
                startActivity(intent);
            }
        });
    }
}

Main2Activity.java

package com.example.madhur.intentclear;

import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.io.FileOutputStream;
import java.io.IOException;

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);


        final TextView tv1=findViewById(R.id.textView);
        final TextView tv2=findViewById(R.id.textView2);
        final TextView tv3=findViewById(R.id.textView3);

        Button button=findViewById(R.id.button);
        Button button1=findViewById(R.id.button1);
        Button button2=findViewById(R.id.button2);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bundle intent=getIntent().getExtras();
                tv1.setText(intent.getString("tv1"));
                tv2.setText(intent.getString("tv2"));
                tv3.setText(intent.getString("tv3"));
            }
        });

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String clear="";

                tv1.setText(clear);
                tv2.setText(clear);
                tv3.setText(clear);
               m1();

            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
Intent intent1=new Intent(Main2Activity.this,MainActivity.class);
startActivity(intent1);
            }
        });
    }
    public void m1()
    {String clear="";
        try {

            FileOutputStream fileOutputStream;
            FileOutputStream fileOutputStream2;
            FileOutputStream fileOutputStream3;
            fileOutputStream = openFileOutput("et1.txt", Context.MODE_PRIVATE);
            fileOutputStream.write(clear.getBytes());

            fileOutputStream2 = openFileOutput("et2.txt", Context.MODE_PRIVATE);
            fileOutputStream2.write(clear.getBytes());

            fileOutputStream3 = openFileOutput("et3.txt", Context.MODE_PRIVATE);
            fileOutputStream3.write(clear.getBytes());

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="com.example.madhur.intentclear.MainActivity">

    <android.support.constraint.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.13" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.87" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.06" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.18" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.29" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.43" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline7"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.58" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline8"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.73" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline9"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.82" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline10"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.95" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline11"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.24" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline12"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.77" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:ems="10"
        android:inputType="textPersonName"
       android:hint="Enter name"
        app:layout_constraintBottom_toTopOf="@+id/guideline4"
        app:layout_constraintEnd_toStartOf="@+id/guideline2"
        app:layout_constraintStart_toStartOf="@+id/guideline"
        app:layout_constraintTop_toTopOf="@+id/guideline3" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="0dp"
        android:hint="Enter phone number"
        android:layout_height="0dp"
        android:ems="10"
        android:inputType="textPersonName"

        app:layout_constraintBottom_toTopOf="@+id/guideline6"
        app:layout_constraintEnd_toStartOf="@+id/guideline2"
        app:layout_constraintStart_toStartOf="@+id/guideline"
        app:layout_constraintTop_toTopOf="@+id/guideline5" />

    <EditText
        android:id="@+id/editText3"
        android:layout_width="0dp"
        android:hint="Enter Email Adress"
        android:layout_height="0dp"
        android:ems="10"
        android:inputType="textPersonName"

        app:layout_constraintBottom_toTopOf="@+id/guideline8"
        app:layout_constraintEnd_toStartOf="@+id/guideline2"
        app:layout_constraintStart_toStartOf="@+id/guideline"
        app:layout_constraintTop_toTopOf="@+id/guideline7" />

    <Button
        android:id="@+id/button"
        android:layout_width="0dp"
        android:layout_height="0dp"
android:text="SAVE"
        app:layout_constraintBottom_toTopOf="@+id/guideline10"
        app:layout_constraintEnd_toStartOf="@+id/guideline12"
        app:layout_constraintStart_toStartOf="@+id/guideline11"
        app:layout_constraintTop_toTopOf="@+id/guideline9" />
</android.support.constraint.ConstraintLayout>

activity_Main2.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="com.example.madhur.intentclear.Main2Activity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="0dp"

        app:layout_constraintBottom_toTopOf="@+id/guideline16"
        app:layout_constraintEnd_toStartOf="@+id/guideline13"
        app:layout_constraintStart_toStartOf="@+id/guideline14"
        app:layout_constraintTop_toTopOf="@+id/guideline15" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="0dp"
        android:layout_height="0dp"

        app:layout_constraintBottom_toTopOf="@+id/guideline19"
        app:layout_constraintEnd_toStartOf="@+id/guideline13"
        app:layout_constraintStart_toStartOf="@+id/guideline14"
        app:layout_constraintTop_toTopOf="@+id/guideline20" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="0dp"
        android:layout_height="0dp"

        app:layout_constraintBottom_toTopOf="@+id/guideline17"
        app:layout_constraintEnd_toStartOf="@+id/guideline13"
        app:layout_constraintStart_toStartOf="@+id/guideline14"
        app:layout_constraintTop_toTopOf="@+id/guideline18" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline13"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_begin="249dp" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline14"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.33854166" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline15"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.031311154" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline16"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.13" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline17"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.38" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline18"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.29" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline19"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.26" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline20"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.16" />

    <Button
        android:id="@+id/button"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="52dp"
        android:text="SHOW TEXT"
        app:layout_constraintEnd_toStartOf="@+id/guideline13"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="@+id/guideline14"
        app:layout_constraintTop_toTopOf="@+id/guideline17" />

    <Button
        android:id="@+id/button1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="44dp"
        android:text="CLEAR TEXT"
        app:layout_constraintEnd_toStartOf="@+id/guideline13"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="@+id/guideline14"
        app:layout_constraintTop_toBottomOf="@+id/button" />

    <Button
        android:id="@+id/button2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="48dp"
        android:text="BACK"
        app:layout_constraintEnd_toStartOf="@+id/guideline13"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="@+id/guideline14"
        app:layout_constraintTop_toBottomOf="@+id/button1" />
</android.support.constraint.ConstraintLayout>