[Android Studio] Chapter 8 연습문제

[연습문제]

 

6

안드로이드 11 AVD로 하려니까 안돼서 안드로이드 9 AVD 새로 만들어서 실행... 보안 이슈로 SD카드 접근이 안드로이드 10부터 안된다고 본 것 같은데 그것때문인 것 같다...

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.cookandroid.a8_1">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <application
        android:requestLegacyExternalStorage="true"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.81">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

activitiy_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:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/datePicker1"
        android:calendarViewShown="false"
        android:datePickerMode="spinner"/>

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/edtDiary"
        android:background="#00ff00"
        android:lines="8"/>
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btnWrite"
        android:enabled="false"
        android:text="BUTTON"/>

</LinearLayout>

Java

package com.cookandroid.a8_1;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

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

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.FileNameMap;
import java.text.SimpleDateFormat;
import java.time.Year;
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);

        ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},MODE_PRIVATE);

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

        final String sdCard = Environment.getExternalStorageDirectory().getAbsolutePath();
        final File myDiary = new File(sdCard+"/myDiary");
        myDiary.mkdirs();

        // 추가
        fileName = sdCard + "/myDiary/" + Integer.toString(cYear) + "_" + Integer.toString(cMonth+1) + "_" + Integer.toString(cDay) + ".txt";
        String str = readDiary(fileName);
        edtDiary.setText(str);
        btnWrite.setEnabled(true);

        dp.init(cYear, cMonth, cDay, new DatePicker.OnDateChangedListener() {
            @Override
            public void onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                fileName = sdCard + "/myDiary/" + 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() {
            @Override
            public void onClick(View v) {
                try{
                    FileOutputStream outFs = new FileOutputStream(fileName);
                    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;
        try{
            //inFs = openFileInput(fName);
            FileInputStream inFs = new FileInputStream(fName);
            byte[] txt = new byte[500];
            inFs.read(txt);
            inFs.close();
            diaryStr = (new String(txt)).trim();
            btnWrite.setText("수정하기");
        }catch (IOException e){
            edtDiary.setHint("일기 없음");
            btnWrite.setText("새로 저장");
        }

        return diaryStr;
    }

}

 

7

myPictureView.java만 살짝 바꿔주면 됨!

 

activitiy_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"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btnPrev"
            android:layout_weight="1"
            android:text="  이전 그림  "/>

        <TextView
            android:layout_width="100dp"
            android:layout_height="wrap_content"
            android:id="@+id/tv"
            android:gravity="center" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btnNext"
            android:layout_weight="1"
            android:text="  다음 그림  "/>
    </LinearLayout>

    <com.cookandroid.a8_2.myPictureView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/myPictureView1"/>
</LinearLayout>

 

MainActivity.java

package com.cookandroid.a8_2;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

import android.Manifest;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import org.w3c.dom.Text;

import java.io.File;

public class MainActivity extends AppCompatActivity {
    Button btnPrev, btnNext;
    myPictureView myPicture;
    int curNum;
    File[] imageFiles;
    String imageFnames, curPage;
    TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("간단 이미지 뷰어");

        ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, MODE_PRIVATE);
        btnPrev = (Button) findViewById(R.id.btnPrev);
        btnNext = (Button) findViewById(R.id.btnNext);
        myPicture = (myPictureView) findViewById(R.id.myPictureView1);
        tv = (TextView) findViewById(R.id.tv);

        imageFiles = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/Pictures").listFiles();
        imageFnames = imageFiles[0].toString();
        myPicture.imagePath = imageFnames;

        curPage = "1"+"/"+(imageFiles.length-1); //분명 파일 3갠데 4개로 떠서 -1 추가... 뭐가 문제지...?
        tv.setText(curPage);


        btnPrev.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (curNum <=0){
                    curNum=imageFiles.length-2;
                }else{
                    curNum --;
                }

                imageFnames = imageFiles[curNum].toString();
                myPicture.imagePath=imageFnames;
                curPage = (curNum+1)+"/"+(imageFiles.length-1);
                tv.setText(curPage);
                myPicture.invalidate();
            }
        });

        btnNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(curNum>=imageFiles.length-2){
                    curNum = 0;
                }else{
                    curNum ++;
                }
                imageFnames = imageFiles[curNum].toString();
                myPicture.imagePath=imageFnames;
                curPage = (curNum+1)+"/"+(imageFiles.length-1);
                tv.setText(curPage);
                myPicture.invalidate();
            }
        });

    }
}

myPictureView.java

package com.cookandroid.a8_2;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.Nullable;

public class myPictureView extends View {
    String imagePath = null;
    public myPictureView(Context context, @Nullable AttributeSet attrs){
        super(context, attrs);
    }

    protected void onDraw(Canvas canvas){

        super.onDraw(canvas);
        if (imagePath != null){
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            
            // 원래 코드
            //canvas.drawBitmap(bitmap, 0,0,null);
            
            // 가운데로 맞추기
            canvas.drawBitmap(bitmap, (canvas.getWidth()-bitmap.getWidth())/2,(canvas.getHeight()-bitmap.getHeight())/2,null);
                        
            bitmap.recycle();

        }


    }
}