Android Studio 7일차

inputstream,outputstream 연습

package com.example.test19;

import androidx.appcompat.app.AppCompatActivity;

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

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

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

        Button btWrite = findViewById(R.id.btWrite);
        Button btRead = findViewById(R.id.btRead);

        btWrite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    FileOutputStream fos = openFileOutput("file.txt", Context.MODE_PRIVATE);
                    String str = "hello,world";
                    fos.write(str.getBytes());
                    fos.close();
                    Toast.makeText(getApplicationContext(),"file.txt created", Toast.LENGTH_LONG).show();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }); // write event
        btRead.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    FileInputStream fis = openFileInput("file.txt");
                    byte[] txt = new byte[30];
                    fis.read(txt);
                    // fis 객체에서 txt바이트 배열로 문자값을 저장.
                    String str = new String(txt);
                    Toast.makeText(getApplicationContext(),str,Toast.LENGTH_LONG).show();
                    fis.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}

 

간단 일기장 만들기

<?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="wrap_content"
        android:layout_height="wrap_content"
        android:datePickerMode="spinner"
        android:calendarViewShown="false"
        android:layout_gravity="center"
        />

    <EditText
        android:id="@+id/edtDiary"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:ems="10"
        android:inputType="textPersonName"
        android:background="#88ff88"
        android:minHeight="48dp"
        android:lines="8"
        android:hint="write"/>

    <Button
        android:id="@+id/btWrite"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button"
        android:enabled="false"/>

</LinearLayout>

레이아웃

package com.example.test19;

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.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 = findViewById(R.id.datePicker1);
        edtDiary = findViewById(R.id.edtDiary);
        btnWrite = findViewById(R.id.btWrite);

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

        fileName = Integer.toString(cYear) + "_"
                + Integer.toString(cMonth + 1) + "_"
                + Integer.toString(cDay) + ".txt";
        // month 0~11
        String str = readDiary(fileName);
        edtDiary.setText(str);
        btnWrite.setEnabled(true);


        // 데이터피커 초기화, file_read
        dp.init(cYear, cMonth, cDay, new DatePicker.OnDateChangedListener() {
            public void onDateChanged(DatePicker view, int year,
                                      int monthOfYear, int dayOfMonth) {
                fileName = Integer.toString(year) + "_"
                        + Integer.toString(monthOfYear + 1) + "_"
                        + Integer.toString(dayOfMonth) + ".txt";
                // month 0~11
                String str = readDiary(fileName);
                edtDiary.setText(str);
                btnWrite.setEnabled(true);
            }
        });


        // file_write
        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) {
                }
            }
        });
    }
    String readDiary(String fName) {
        String diaryStr = null;
        FileInputStream inFs;

        try {
            inFs = openFileInput(fName);
            byte[] txt = new byte[500];
            inFs.read(txt);// 지정한 날짜의 파일을 읽어서, fis 에 저장.
            inFs.close();
            diaryStr = (new String(txt)).trim();
            // trim : 문자열을 지정하면, 해당 문자열로 빈 공간을 채우고,
            // 문자열을 지정하지 않는다면, 좌우의 공백 제거
            btnWrite.setText("수정 하기");
        } catch (IOException e) {
            edtDiary.setHint("일기 없음");
            btnWrite.setText("새로 저장");
        }
        return diaryStr;
    }

}

기능부분.