Android] 값을 입력 받아서 Gson 사용하기

EditText에 값을 입력 받은 후 Gson을 사용하여 원하는 형식으로 출력하기 

 

1. build.gradle에 코드 추가

implementation 'com.google.code.gson:gson:2.9.0'

 

 

2.activity_main.xml

코드

<?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">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="이름을 입력하십시오"
        android:id="@+id/edit_name"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="번호를 입력하십시오"
        android:id="@+id/edit_num"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="나이를 입력하십시오"
        android:id="@+id/edit_age"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/save_btn"
        android:text="값 저장하기"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/rtn_btn"
        android:text="값 불러오기"
        />
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/text_info"
        android:text="값"
        android:textSize="20sp"
        />
</LinearLayout>

 

3.Info.java

java 파일 생성

package com.example.gson_ex;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Info {

    private String name;

    private int num;


    private int age;

    public Info(String name, int num, int age){
        this.name = name;
        this.age = age;
        this.num = num;
    }

    public String toString(){
        return "정보[이름 : "+ name+", 나이 : "+age+",번호 : "+num+"]";
    }

}

 

4.MainActivity.java

package com.example.gson_ex;

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.google.gson.Gson;

public class MainActivity extends AppCompatActivity {

    Gson gson;
    String name;
    int num;
    int age;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        EditText editName = (EditText) findViewById(R.id.edit_name);
        EditText editAge = (EditText) findViewById(R.id.edit_age);
        EditText editNum = (EditText) findViewById(R.id.edit_num);
        Button saveBtn = (Button) findViewById(R.id.save_btn);
        saveBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                name = editName.getText().toString();
                num = Integer.parseInt(editNum.getText().toString());
                age = Integer.parseInt(editAge.getText().toString());
            }
        });
       Button rtnBtn = (Button) findViewById(R.id.rtn_btn);
       rtnBtn.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View view) {
               Info info = new Info(name,num,age);
               gson = new Gson();
               String infoJson = gson.toJson(info.toString());
               TextView textInfo = (TextView) findViewById(R.id.text_info);
               textInfo.setText(infoJson);
               System.out.println(infoJson);
           }
       });
    }
}

5, 동작

 

 1) 값 저장하기 클릭

 

2) 값 불러오기 클릭