Android多媒体之音频播放

Posted 2021-07-27 背时的哥哥

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文章目录

1.前言

在android中播放音频文件一般使用MediaPlayer类实现。通过调用其方法可实现对本地音频文件的操作。

2.前期准备

1.在/storage/emulate/0目录下创建Music目录用于存放音频文件

在这里插入图片描述

2.添加音频文件到Music中

在这里插入图片描述

3.前台页面

1.编写播放列表

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:textColor="@color/cardview_dark_background"
        android:textAlignment="center"
        android:text="music list"
        android:background="@color/cardview_shadow_start_color"
        android:layout_marginBottom="30dp"
        android:gravity="center_horizontal" />

    <ListView
        android:id="@+id/music_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

<?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="wrap_content"
    tools:context=".MainActivity"
    >

   <TextView
       android:id="@+id/musicName"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"/>
</LinearLayout>

2.播放页面

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_marginBottom="50dp"
        android:textAlignment="center"
        android:id="@+id/musicTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal" />

    <Button
        android:id="@+id/play"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Play"/>

    <Button
        android:id="@+id/pause"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Pause"/>

    <Button
        android:id="@+id/stop"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Stop"/>

</LinearLayout>

4.后台逻辑

1.创建实体类

package entity;

public class Music {
    private String musicName;

    public String getMusicName() {
        return musicName;
    }

    public void setMusicName(String musicName) {
        this.musicName = musicName;
    }

    public Music() {
    }
}

2.编写适配器

package com.example.cameraalbumtest;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.List;

import entity.Music;

public class MusicAdapter extends ArrayAdapter<Music>{
    private int resourceId;
    public MusicAdapter(@NonNull Context context, int resource, List<Music> objects) {
        super(context, resource,objects);
        resourceId = resource;
    }


    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        Music music = getItem(position);
        View view;
        if (convertView == null){
            view = LayoutInflater.from(getContext()).inflate(resourceId,parent,false);
        }else {
            view = convertView;
        }
        TextView textView = view.findViewById(R.id.musicName);
        textView.setText(music.getMusicName());
        return view;
    }
}

3.播放列表

package com.example.cameraalbumtest;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;

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

import entity.Music;

public class MusicList extends AppCompatActivity {

    private List<Music> list = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_music_list);
        //获取该文件夹下的文件
        File file = new File(Environment.getExternalStorageDirectory(),"Music");
        File[] files = file.listFiles();
        //调用方法获取后缀为MP3的文件
        initMusic(files);
        //将结果交给适配器进行装配
        MusicAdapter musicAdapter = new MusicAdapter(MusicList.this,R.layout.music_item,list);
        ListView listView = findViewById(R.id.music_list);
        listView.setAdapter(musicAdapter);
        //设置点击事件
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent intent = new Intent(MusicList.this,MediaPlay.class);
                Music music = list.get(position);
                String musicName = music.getMusicName();
                intent.putExtra("musicName",musicName);
                startActivity(intent);
            }
        });
    }

    //读取文件中的MP3文件
    public void initMusic(File[] files){
        for (File file : files) {
            Music music = new Music();
            if (file.getName().endsWith(".mp3")){
                music.setMusicName(file.getName());
                list.add(music);
            }

        }
    }
}

4.音频操作

package com.example.cameraalbumtest;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;

public class MediaPlay extends AppCompatActivity implements View.OnClickListener {

    private MediaPlayer mediaPlayer = new MediaPlayer();
    private String musicName;//定义音乐名

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

        //获取传来的musicName
        Intent intent = getIntent();
        musicName = intent.getStringExtra("musicName");

        Button play = findViewById(R.id.play);
        Button pause = findViewById(R.id.pause);
        Button stop = findViewById(R.id.stop);
        play.setOnClickListener(this);
        pause.setOnClickListener(this);
        stop.setOnClickListener(this);

        //显示歌曲名称
        TextView textView = findViewById(R.id.musicTitle);
        textView.setText("歌曲名："+musicName);

        //动态获取访问存储权限
        if (ContextCompat.checkSelfPermission(MediaPlay.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(MediaPlay.this,new String[]{
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            },1);
        }else {
            //初始化MediaPlay
            initMediaPlay(musicName);
        }
    }


    //初始化mediaPlayer
    private void initMediaPlay(String musicName){
        try{
            //根据musicName创建file
            File file = new File(Environment.getExternalStorageDirectory(),"Music/"+musicName);
            mediaPlayer.setDataSource(file.getPath());//指定音频文件的路径
            mediaPlayer.prepare();//让MediaPlayer进入到准备状态
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    //获取申请权限结果
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode){
            case 1:
                if (grantResults.length>0&&grantResults[0]==PackageManager.PERMISSION_GRANTED){
                    initMediaPlay(musicName);
                }else {
                    Toast.makeText(this,"拒绝权限将无法使用程序",Toast.LENGTH_SHORT).show();
                    finish();
                }
                break;
            default:
        }
    }

    //设置点击事件
    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.play:
                if (!mediaPlayer.isPlaying()){
                    mediaPlayer.start();
                }
                break;
            case R.id.pause:
                if (mediaPlayer.isPlaying()){
                    mediaPlayer.pause();
                }
                break;
            case R.id.stop:
                if (mediaPlayer.isPlaying()){
                    mediaPlayer.reset();
                    initMediaPlay(musicName);
                }
                break;
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mediaPlayer!=null){
            mediaPlayer.stop();
            mediaPlayer.release();
        }
    }
}```

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