[안드로이드 자바] 저장소 접근하여 이미지뷰어 만들기(ExternalStorageDirectory)

 

 

디자인

 

프로젝트 설명

저장장치에 접근하여 이미지를 표시한다

이전그림 버튼을 누르면 이전 순서의 이미지가 나오며 다음그림 버튼을 누르면 다음 순서의 그림이 나온다

※ AVD 실행 후 이미지를 저장해야 실습 가능

※먼저 저장장치 접근 권한을 허용하도록 한다

AndroidManifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

 

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="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textSize="25dp"
            android:gravity="center"
            android:id="@+id/tvNumber"/>

        <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.sample.sdimageview.myPictureView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/myPicthreView1"/>
</LinearLayout>

 

myPictureView.java

package com.sample.sdimageview;

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);
    }
    @Override
    protected void onDraw(Canvas canvas){

        super.onDraw(canvas);
        if (imagePath != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            canvas.drawBitmap(bitmap, 0, 0, null);
            bitmap.recycle();
        }
    }
}

 

 

MainActivity.java

package com.sample.sdimageview;

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 java.io.File;

public class MainActivity extends AppCompatActivity {

    Button btnprev, btnNext;
    myPictureView myPicture;
    TextView tvNumber;
    int curNum = 0;
    File[] imageFiles;
    String imageFname;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("간단 이미지 뷰어");
        ActivityCompat.requestPermissions(this, new String[] {android.
                Manifest.permission.WRITE_EXTERNAL_STORAGE}, MODE_PRIVATE);

        btnprev = (Button) findViewById(R.id.btnPrev);
        btnNext = (Button) findViewById(R.id.btnNext);
        myPicture = (myPictureView) findViewById(R.id.myPicthreView1);
        tvNumber = (TextView) findViewById(R.id.tvNumber);

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

        btnprev.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (curNum <= 0) {
                    curNum = imageFiles.length-1;
                    imageFname = imageFiles[curNum].toString();
                    myPicture.imagePath = imageFname;
                    myPicture.invalidate();
                } else {
                    curNum--;
                    imageFname = imageFiles[curNum].toString();
                    myPicture.imagePath = imageFname;
                    myPicture.invalidate();
                }
                tvNumber.setText((curNum + 1) + " / " + imageFiles.length);
            }
        });

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