[Android] 간단 일기장

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">
    <DatePicker
        android:id="@+id/datePicker1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1"
        android:datePickerMode="spinner"
        android:calendarViewShown="false"/>
    <EditText
        android:id="@+id/edtDiary"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:background="#00ff00"
        android:lines="8"/>
    <Button
        android:id="@+id/btnWrite"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:enabled="false"
        android:text="Button"/>

</LinearLayout>

MainActivity.java

package com.example.project8_1;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.Toast;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Calendar;

public class MainActivity extends AppCompatActivity {
    DatePicker dp;
    EditText edtDiary;
    Button btnWrite;
    String fileName;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("간단 일기장");

        dp=(DatePicker) findViewById(R.id.datePicker1);
        edtDiary=(EditText) findViewById(R.id.edtDiary);
        btnWrite = (Button) findViewById(R.id.btnWrite);

        Calendar cal = Calendar.getInstance();
        int cYear = cal.get(Calendar.YEAR);
        int cMonth = cal.get(Calendar.MONTH);
        int cDay = cal.get(Calendar.DAY_OF_MONTH);

        //데이트피커의 초깃값이 cYear,cMonth,cDay로 설정된다.
        dp.init(cYear,cMonth,cDay, new DatePicker.OnDateChangedListener(){
            //데이트피커에 설정된 연,월,일을 사용 할 수 있게 해준다.
            public void onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth){
                fileName = Integer.toString(year)+"-"+Integer.toString(monthOfYear+1)+"-"+Integer.toString(dayOfMonth)+".txt";
                String str = readDiary(fileName);
                edtDiary.setText(str);
                btnWrite.setEnabled(true);
            }
        });
        btnWrite.setOnClickListener(new View.OnClickListener(){
            public void onClick(View V){
                try{
                    FileOutputStream outFs = openFileOutput(fileName, Context.MODE_PRIVATE);
                    String str = edtDiary.getText().toString();
                    outFs.write(str.getBytes());
                    outFs.close();
                    Toast.makeText(getApplicationContext(),fileName+"이 저장됨", Toast.LENGTH_SHORT).show();
                }catch (IOException e){}
            }
        });
    }
    //fName의 파일이 존재하는지 안하는지 확인해주는 함수
    String readDiary(String fName){
        String diaryStr = null;
        FileInputStream inFs;
        try{
            inFs = openFileInput(fName);
            byte[] txt = new byte[500];
            inFs.read(txt);
            diaryStr = (new String(txt)).trim();
            btnWrite.setText("수정하기");
        }catch(IOException e){
            edtDiary.setHint("일기 없음");
            btnWrite.setText("새로 저장");
        }
        return diaryStr;
    }
}

 

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