[Android] 간단 MP3 플레이어 만들기

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="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="6"
        android:orientation="horizontal">
        <ListView
            android:id="@+id/listViewMP3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:orientation="horizontal">
        <Button
            android:id="@+id/btnPlay"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginRight="5dp"
            android:layout_weight="1"
            android:backgroundTint="#50000000"
            android:textColor="@color/black"
            android:text="듣기"/>
        <Button
            android:id="@+id/btnStop"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:backgroundTint="#50000000"
        android:textColor="@color/black"
        android:text="중지"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:id="@+id/tvMP3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:text="실행중인 음악 : "/>
        <ProgressBar
            android:id="@+id/pbMP3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:visibility="invisible"/>
    </LinearLayout>

</LinearLayout>

MainActivity.java

package com.example.mp3player;

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

import android.Manifest;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    ListView listViewMP3;
    Button btnPlay, btnStop;
    TextView tvMP3;
    ProgressBar pbMP3;

    ArrayList<String> mp3List;
    String selectedMP3;

    String mp3Path = Environment.getExternalStorageDirectory().getPath()+"/";
    MediaPlayer mPlayer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("간단 MP3 플레이어");

        ActivityCompat.requestPermissions(this,new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE},MODE_PRIVATE);
        mp3List = new ArrayList<String>();
        // 일단 모든 파일을 저장해 준다.
        File[] listFiles = new File(mp3Path).listFiles();
        String fileName, extName;
        // 모든 파일 중에서 확장자명이 mp3인 파일들만 저장한다.
        for(File file: listFiles){
            fileName = file.getName();
            Toast.makeText(getApplicationContext(),fileName,Toast.LENGTH_SHORT).show();
            extName = fileName.substring(fileName.length()-3);
            if(extName.equals((String) "mp3"))
                mp3List.add(fileName);
        }

        listViewMP3 = (ListView) findViewById(R.id.listViewMP3);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_single_choice,mp3List);
        listViewMP3.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
        listViewMP3.setAdapter(adapter);
        listViewMP3.setItemChecked(0,true);

        listViewMP3.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                selectedMP3 = mp3List.get(arg2);
            }
        });
        // 리스트뷰를 클릭하지 않고 <듣기>를 클릭할 때 오류가 발생하지 않게 하기 위한 코드
        //selectedMP3 = mp3List.get(0);

        btnPlay = (Button) findViewById(R.id.btnPlay);
        btnStop = (Button) findViewById(R.id.btnStop);
        tvMP3 = (TextView) findViewById(R.id.tvMP3);
        pbMP3 = (ProgressBar) findViewById(R.id.pbMP3);

        btnPlay.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try{
                    mPlayer= new MediaPlayer();
                    mPlayer.setDataSource(mp3Path+selectedMP3);
                    // prepare 후에 start
                    mPlayer.prepare();
                    mPlayer.start();
                    btnPlay.setClickable(false);
                    btnStop.setClickable(true);
                    tvMP3.setText("실행중인 음악 : "+selectedMP3);
                    pbMP3.setVisibility(View.VISIBLE);
                }catch(IOException e){

                }
            }
        });
        btnStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // stop하고 꼭 reset
                mPlayer.stop();
                mPlayer.reset();
                btnPlay.setClickable(true);
                btnStop.setClickable(false);
                tvMP3.setText("실행중인 음악 : ");
                pbMP3.setVisibility(View.INVISIBLE);
            }
        });
        btnStop.setClickable(false);
    }
}

 

실행 화면

sd 카드에서 mp3파일 읽기 실패로 실행 화면 없음.