안드로이드- 글 적고 저장 누르면 다시 실행시켰을 때 저장됨

- 글 적고 저장 누르면 다시 실행시켰을 때 저장되어 있음 .

 

<MainaActivity.java>

package com.example.shared_p_app;

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;
import android.graphics.Color;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    private SharedPreferences preferences;
    private SharedPreferences.Editor editor;
    private int SelectedColor;
    EditText editText;
    Button btnRed, btnGreen, btnBlue;
    Button btnSave, btnRemove;

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

        editText = findViewById(R.id.editText);
        btnRed = findViewById(R.id.btnRed);
        btnGreen = findViewById(R.id.btnGreen);
        btnBlue = findViewById(R.id.btnBlue);
        btnSave = findViewById(R.id.btnSave);
        btnRemove = findViewById(R.id.btnRemove);

        setBtnColorListener();
        setBtnPreferenceListener();

        preferences = PreferenceManager.getDefaultSharedPreferences(this);
        editor = preferences.edit();

        initializeValue();
    }

    public void setBtnColorListener() {
        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                switch (v.getId()){
                    case R.id.btnRed:
                        SelectedColor = Color.RED;
                        editText.setTextColor(Color.RED);
                        break;
                    case R.id.btnGreen:
                        SelectedColor = Color.GREEN;
                        editText.setTextColor(Color.GREEN);
                        break;
                    case R.id.btnBlue:
                        SelectedColor = Color.BLUE;
                        editText.setTextColor(Color.BLUE);
                        break;
                }
            }
        };
        btnRed.setOnClickListener(listener);
        btnGreen.setOnClickListener(listener);
        btnBlue.setOnClickListener(listener);

    }

    public void initializeValue() {
        editText.setText(preferences.getString("text", "저장된 데이터가 없음"));
        editText.setTextColor(preferences.getInt("color", Color.GREEN));
    }

    public void setBtnPreferenceListener() {
        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                switch (v.getId()){
                    //데이터 저장하기
                    case R.id.btnSave:
                        editor.putInt("color", SelectedColor);
                        editor.putString("text",editText.getText().toString());
                        editor.apply();
                        break;
                    // 데이터 제거하기
                    case R.id.btnRemove:
                        editor.remove("color");
                        editor.remove("text");
                        editor.apply();
                        break;
                }
            }
        };
        btnSave.setOnClickListener(listener);
        btnRemove.setOnClickListener(listener);

    }

}

<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">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btnSave"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="2dp"
            android:layout_weight="1"
            android:text="저장" />

        <Button
            android:id="@+id/btnRemove"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="2dp"
            android:layout_weight="1"
            android:text="제거" />
    </LinearLayout>

    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:hint="텍스트를 입력하세요" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btnRed"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="2dp"
            android:layout_weight="1"
            android:text="RED" />

        <Button
            android:id="@+id/btnGreen"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="2dp"
            android:layout_marginRight="2dp"
            android:layout_weight="1"
            android:text="GREEN" />

        <Button
            android:id="@+id/btnBlue"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_marginLeft="2dp"
            android:text="Button" />
    </LinearLayout>
</LinearLayout>