android第三次作业

界面：


主要代码：
1.定义一个工具类，在这个类中获取音频文件，并且对歌曲名、歌手和时间等进行格式规范：

package com.example.administrator.music;import android.content.Context;
import android.database.Cursor;
import android.provider.MediaStore;import java.util.ArrayList;
import java.util.List;
/*** Created by liuliu on 2018/1/14.*///工具类
public class Utils {//定义一个集合，存放从本地读取到的内容public static List<Song> list;public static Song song;public static List<Song> getmusic(Context context) {list = new ArrayList<>();Cursor cursor = context.getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, MediaStore.Audio.AudioColumns.IS_MUSIC);if (cursor != null) {while (cursor.moveToNext()) {song = new Song();song.song = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME));song.singer = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST));song.path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA));song.duration = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DURATION));song.size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.SIZE));//                把歌曲名字和歌手切割开if (song.size > 1000 * 800) {if (song.song.contains("-")) {String[] str = song.song.split("-");song.singer = str[0];song.song = str[1];}list.add(song);}}}cursor.close();return list;}//    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;}}}

2.定义一个布局text.xml用于展示每一个音频文件的内容，使用适配器把把内容映射到主布局文件中的ListView中去：

class MyAdapter extends BaseAdapter {Context context;List<Song> list;public MyAdapter(MainActivity mainActivity, List<Song> list) {this.context = mainActivity;this.list = list;}@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int i) {return list.get(i);}@Overridepublic long getItemId(int i) {return i;}@Overridepublic View getView(int i, View view, ViewGroup viewGroup) {Myholder myholder;if (view == null) {myholder = new Myholder();view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.text, null);myholder.t_position = view.findViewById(R.id.t_postion);myholder.t_song = view.findViewById(R.id.t_song);myholder.t_singer = view.findViewById(R.id.t_singer);myholder.t_duration = view.findViewById(R.id.t_duration);view.setTag(myholder);} else {myholder = (Myholder) view.getTag();}myholder.t_song.setText(list.get(i).song.toString());myholder.t_singer.setText(list.get(i).singer.toString());String time = Utils.formatTime(list.get(i).duration);myholder.t_duration.setText(time);myholder.t_position.setText(i + 1 + "");return view;}class Myholder {TextView t_position, t_song, t_singer, t_duration;}}

3.定义播放play()、暂停pause()、停止stop()和循环播放loop()方法:

    public void play(String path) {try {// 重置音频文件，防止多次点击会报错mediaPlayer.reset();// 调用方法传进播放地址mediaPlayer.setDataSource(path);//  异步准备资源，防止卡顿mediaPlayer.prepareAsync();// 调用音频的监听方法，音频准备完毕后响应该方法进行音乐播放mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {@Overridepublic void onPrepared(MediaPlayer mediaPlayer) {mediaPlayer.start();//设置循环播放。loop();}});} catch (Exception e) {e.printStackTrace();}}protected void play1() {mediaPlayer.start();//设置循环播放。loop();}protected void pause() {mediaPlayer.pause();button2.setEnabled(true);button2.setBackgroundColor(getResources().getColor(R.color.colorPrimary));}protected void stop() {if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.stop();mediaPlayer.release();mediaPlayer = null;button2.setEnabled(true);Toast.makeText(this, "停止播放", Toast.LENGTH_LONG).show();}}protected  void loop(){mediaPlayer.setLooping(true);
}

4.给按钮添加点击事件：

    class myListener implements View.OnClickListener {@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.button2://避免重复播放，把播放按钮设置为不可用button2.setEnabled(false);button2.setBackgroundColor(Color.GRAY);//String p0 = list.get(current).path;//获得歌曲的地址if(one<1){String p = list.get(current).path;play(p);one++;}else {play1();}break;case R.id.button3:pause();break;case R.id.button1:if (current > 0) {current = current - 1;String p1 = list.get(current).path;//获得歌曲的地址play(p1);} else {current = list.size() - 1;String p1 = list.get(current).path;//获得歌曲的地址play(p1);}break;case R.id.button4:if (current + 1 < list.size()) {current = current + 1;String p2 = list.get(current).path;//获得歌曲的地址play(p2);} else {current = 0;String p2 = list.get(current).path;//获得歌曲的地址play(p2);}break;case  R.id.button5:stop();default:break;}}}

代码：https://git.coding.net/zwp598692456/androidmusic.git
app:https://coding.net/s/6d12c6ac-6efb-43ec-a2ab-f1332e3e5b57