今天已经全部完成从手机本地SD卡中读取歌曲信息，并实现了音乐的播放，暂停，上一首，下一首的功能。鉴于明天满课，所以明天打算把这个音乐播放的布局完整一下，并把一些显示信息的纰漏和不完整的信息弄好。
package com.example.keeprunning6; import android.Manifest; import android.content.ContentResolver; import android.content.pm.PackageManager; import android.database.Cursor; import android.media.MediaPlayer; import android.net.Uri; import android.os.Bundle; import android.provider.MediaStore; import android.view.View; import android.widget.AdapterView; import android.widget.ImageView; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import androidx.core.content.ContextCompat; import java.io.IOException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Date; public class MainActivity extends AppCompatActivity { ImageView lastIv,playIv,nextIv,pauseIv; //音乐列表试图 private ListView listView; //音乐列表 private ArrayList<LocalMusicBean> list=new ArrayList<>(); //当前播放的音乐以及歌手 private TextView now_music_song,now_music_singer; private LocalMusicAdapter adapter; private int position; // 在播放音乐的位置 int currentPlayPosition=-1; //记录暂停音乐时进度条的位置 int currentPausePositionSong=0; MediaPlayer mediaPlayer; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listView=findViewById(R.id.music_list); now_music_song=findViewById(R.id.local_music_botton_tv_song); now_music_singer=findViewById(R.id.local_music_bottom_tv_singer); playIv=findViewById(R.id.local_music_bottom_iv_play); lastIv=findViewById(R.id.local_music_bottom_iv_last); nextIv=findViewById(R.id.local_music_bottom_iv_next); mediaPlayer=new MediaPlayer(); //自定义数据 adapter=new LocalMusicAdapter(MainActivity.this,list); listView.setAdapter(adapter); //加载本地数据源 localMusicData(); //设置每一项的点击事件 playIv.setOnClickListener(l); lastIv.setOnClickListener(l); nextIv.setOnClickListener(l); listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { //上面的position参数是歌曲在列表中的索引 currentPlayPosition=position; LocalMusicBean musicBean=list.get(position); playMusicPosition(musicBean); } }); } //根据传入对象播放音乐 public void playMusicPosition(LocalMusicBean musicBean) { //底部显示的歌手名和歌曲名 now_music_singer.setText(musicBean.getSinger()); now_music_song.setText(musicBean.getSong()); stopMusic(); //重制多媒体音乐播放器 mediaPlayer.reset(); //改变地址，重新设置路径 try { mediaPlayer.setDataSource(musicBean.getPath()); playMusic(); } catch (IOException e) { e.printStackTrace(); } } //播放音乐的函数 /*根据currentPausePositionSong的数值判断 * 1.从暂停到播放 * 2.从停止到播放 * */ private void playMusic() { if (mediaPlayer!=null&&!mediaPlayer.isPlaying()) { //判断是否暂停，以判断音乐是否从头播放 if (currentPausePositionSong==0) { //从头开始播放 try { //因为之前重制了音乐，所以现在要做准备 mediaPlayer.prepare(); //准别完之后开始播放 mediaPlayer.start(); } catch (IOException e) { e.printStackTrace(); } }else{ //从暂停开始播放 //将进度条挪动到指定的位置上 mediaPlayer.seekTo(currentPausePositionSong); //开始播放 mediaPlayer.start(); } playIv.setImageResource(R.mipmap.icon_pause); } } //暂停音乐的函数 private void pauseMusic() { if (mediaPlayer!=null&&mediaPlayer.isPlaying()) { currentPausePositionSong=mediaPlayer.getCurrentPosition(); mediaPlayer.pause(); playIv.setImageResource(R.mipmap.icon_play); } } //停止音乐的函数 private void stopMusic(){ if(mediaPlayer!=null){ //一暂停，改变currentPausePositionSong的数值为0 currentPausePositionSong=0; //先暂停音乐 mediaPlayer.pause(); //将暂停的音乐的播放条回到最初 mediaPlayer.seekTo(0); //再停止音乐的播放 mediaPlayer.stop(); playIv.setImageResource(R.mipmap.icon_play); } } protected void onDestroy(){ super.onDestroy(); stopMusic(); } private void localMusicData(){ //加载本地存储当中的音乐mp3文件到集合当中 //1.获取ContentResolver对象 ContentResolver resolver=getContentResolver(); //2.获取本地音乐存储的Uri地址 Uri uri= MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; //3.开始查询地址 Cursor cursor=resolver.query(uri,null,null,null,null); //4.遍历Cursor int id=0; while(cursor.moveToNext()){ String song=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE)); String singer=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST)); String album=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM)); id++; //歌曲编号变成String类型 String sid=String.valueOf(id); String path=cursor.getString(cursor.getColumnIndex((MediaStore.Audio.Media.DATA))); // String duration=cursor.getString(cursor.getColumnIndex((MediaStore.Audio.Media.DURATION))); int duration=cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DURATION)); SimpleDateFormat sdf=new SimpleDateFormat("mm:ss"); String time = formatTime(duration); //将一行当中的数据封装到对象当中 LocalMusicBean bean=new LocalMusicBean(sid,song,singer,album,time,path); list.add(bean); } //数据变化，提示适配器更新 adapter.notifyDataSetChanged(); } // 转换歌曲时间的格式 public static String formatTime(int time) { if (time / 1000 % 60 < 10) { String tt = time / 1000 / 60 + ":0" + time / 1000 % 60; return tt; } else { String tt = time / 1000 / 60 + ":" + time / 1000 % 60; return tt; } } View.OnClickListener l = new View.OnClickListener() { @Override public void onClick(View v) { switch(v.getId()){ case R.id.local_music_bottom_iv_last: if (currentPlayPosition==0) { Toast.makeText(MainActivity.this,"这是第一首歌曲，没有上一曲了",Toast.LENGTH_SHORT); return; } currentPlayPosition=currentPlayPosition-1; LocalMusicBean lastBean=list.get(currentPlayPosition); playMusicPosition(lastBean); break; case R.id.local_music_bottom_iv_play: if (currentPlayPosition==-1) { //没有选中要播放的音乐 // Toast.makeText(this,"请选择要播放的音乐",Toast.LENGTH_SHORT).show(); Toast.makeText(MainActivity.this,"请选择要播放的音乐",Toast.LENGTH_SHORT).show(); return; } if (mediaPlayer.isPlaying()) { //此时处于播放状态，需要暂停音乐 pauseMusic(); }else{ //此时没有播放音乐，点击开始播放音乐 playMusic(); } break; case R.id.local_music_bottom_iv_next: if (currentPlayPosition==list.size()-1) { Toast.makeText(MainActivity.this,"这是最后一首歌曲，没有下一曲了",Toast.LENGTH_SHORT); return; } currentPlayPosition=currentPlayPosition+1; LocalMusicBean nextBean=list.get(currentPlayPosition); playMusicPosition(nextBean); break; } } }; }
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