안드로이드 스튜디오 데이터 저장

회전시 데이터 유지

<?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" >

    <TextView
        android:id="@+id/level"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="level : 0"
        android:textSize="20dp"/>

    <Button
        android:id="@+id/level_up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="level up" />

    <TextView
        android:id="@+id/score"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="score : 0"
        android:textSize="20dp"/>

    <Button
        android:id="@+id/score_up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="score up" />
</LinearLayout>

package com.example.cycle_save;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    Button level_up, score_up;
    TextView level, score;
    int mlevel=0, mscore=0;
    public static final String STATE_SCORE = "playerScore";
    public static final String STATE_LEVEL = "playLevel";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        level_up = findViewById(R.id.level_up);
        score_up = findViewById(R.id.score_up);
        level = findViewById(R.id.level);
        score = findViewById(R.id.score);

        level_up.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mlevel++;
                level.setText("level : "+mlevel);
            }
        });
        score_up.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mscore+=100;
                score.setText("score : "+mscore);
            }
        });

        if (savedInstanceState == null){}
        else {
            mlevel = savedInstanceState.getInt(STATE_LEVEL);
            mscore = savedInstanceState.getInt(STATE_SCORE);
            level.setText("level : "+mlevel);
            score.setText("score : "+mscore);
        }
    }
    @Override
    protected void onSaveInstanceState (@NonNull Bundle outState) {
        outState.putInt(STATE_SCORE,mscore);
        outState.putInt(STATE_LEVEL,mlevel);
        super.onSaveInstanceState(outState);
    }//상태 저장
}

 

-> 원래 화면이 돌가면 데이터가 날아가지만 이 데이터를 유지하게 하는 것