基于安卓的音乐播放器(入门级)

【核心代码】

package cn.itcase.dmtplayer;

import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SeekBar;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import java.io.IOException;
import java.sql.Date;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;

public class ZHUMainActivity extends AppCompatActivity implements View.OnClickListener, SeekBar.OnSeekBarChangeListener, MediaPlayer.OnCompletionListener {

    private MediaPlayer mediaPlayer;//播放音频的
    private Button mPreviousBtn;
    private Button mPlayBtn;
    private Button mNextBtn;
    private Button bt1;
    private ListView mListView;
    private List<Song> list;
    private MyAdapter adapter;
    private SeekBar mSeekBar;
    private TextView mCurrentTimeTv;
    private TextView mTotalTimeTv;
    // 记录当前播放歌曲的位置
    private int mCurrentPosition;

    private Handler mHandler=new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message message) {
            // 展示给进度条和当前时间
            int progress = mediaPlayer.getCurrentPosition();
            mSeekBar.setProgress(progress);
            mCurrentTimeTv.setText(parseTime(progress));
            // 继续定时发送数据
            updateProgress();
            return true;
        }
    });
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.zhuactivity_main);
        mediaPlayer = new MediaPlayer();
        mPreviousBtn= (Button) findViewById(R.id.mPreviousBtn);
        mPlayBtn= (Button) findViewById(R.id.mPlayBtn);
        mNextBtn= (Button) findViewById(R.id.mNextBtn);
        bt1=(Button)findViewById(R.id.bt1);
        mCurrentTimeTv= (TextView) findViewById(R.id.current_time_tv);
        mTotalTimeTv= (TextView) findViewById(R.id.total_time_tv);
        mSeekBar= (SeekBar) findViewById(R.id.seek_bar);
        mSeekBar.setOnSeekBarChangeListener(this);
        mPreviousBtn.setOnClickListener(this);
        mPlayBtn.setOnClickListener(this);
        mNextBtn.setOnClickListener(this);
        initView();
    }
    /**
     * 初始化view
     */
    private void initView() {
        mListView = (ListView) findViewById(R.id.main_listview);
        list = new ArrayList<>();
        //把扫描到的音乐赋值给list
        list = MusicUtils.getMusicData(this);
        adapter = new MyAdapter(this,list);
        mListView.setAdapter(adapter);
        mediaPlayer.setOnCompletionListener(this);
        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                mCurrentPosition=i;
                changeMusic(mCurrentPosition);
            }
        });
    }
    @Override
    public void onClick(View view) {
        if (view.getId()==R.id.mPreviousBtn){//上一曲
            changeMusic(--mCurrentPosition);
        }else if (view.getId()==R.id.mPlayBtn){//暂停/播放
            // 首次点击播放按钮，默认播放第0首
            if (mediaPlayer==null){
                changeMusic(0);
            }else {
                if (mediaPlayer.isPlaying()){
                    mediaPlayer.pause();
                }else {
                    mediaPlayer.start();
                }
            }
        }else if (view.getId()==R.id.mNextBtn){// 下一首
            changeMusic(  mCurrentPosition);
        }
    }

    // 基本数据类型和String在方法调用中传递的是值
    // 其他数据类型在方法调用中传递的是引用

    //切歌
    private void changeMusic(int position){
        if (position<0){
            mCurrentPosition = position =list.size()-1;
        }else if (position>list.size()-1){
            mCurrentPosition = position=0;
        }

        if (mediaPlayer==null){
            mediaPlayer=new MediaPlayer();
        }

        try {
            // 切歌之前先重置，释放掉之前的资源
            mediaPlayer.reset();
            // 设置播放源
            mediaPlayer.setDataSource(list.get(position).path);
            // 开始播放前的准备工作，加载多媒体资源，获取相关信息
            mediaPlayer.prepare();

            // 开始播放
            mediaPlayer.start();
        } catch (IOException e) {
            e.printStackTrace();
        }

        // 切歌时重置进度条并展示歌曲时长
        mSeekBar.setProgress(0);
        mSeekBar.setMax(mediaPlayer.getDuration());
        mTotalTimeTv.setText(parseTime(mediaPlayer.getDuration()));

        updateProgress();
    }

    private void updateProgress() {
        // 使用Handler每间隔1s发送一次空消息，通知进度条更新
        Message msg = Message.obtain();// 获取一个现成的消息
        // 使用MediaPlayer获取当前播放时间除以总时间的进度
        int progress = mediaPlayer.getCurrentPosition();
        msg.arg1 = progress;
        mHandler.sendMessageDelayed(msg, INTERNAL_TIME);
    }

    private String parseTime(int oldTime) {
        SimpleDateFormat sdf = new SimpleDateFormat("mm:ss");// 时间格式
        String newTime = sdf.format(new Date(oldTime));
        return newTime;
    }

    private static final int INTERNAL_TIME = 1000;// 音乐进度间隔时间
    @Override
    public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
    }
    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
    }
    // 当手停止拖拽进度条时执行该方法
    // 获取拖拽进度
    // 将进度对应设置给MediaPlayer
    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        int progress = seekBar.getProgress();
        mediaPlayer.seekTo(progress);
    }

    @Override
    public void onCompletion(MediaPlayer mediaPlayer) {
        changeMusic(  mCurrentPosition);
    }
    public void clickk(View view) {
        final exitthis dialog = new exitthis(ZHUMainActivity.this);
        dialog.setTitle("提示");
        dialog.setMessage("是否退出登录？");
        dialog.setNegtive("取消");
        dialog.setPositive("确定");
        dialog.setOnClickBottomListener(new exitthis.OnClickBottomListener() {
            @Override
            public void onPositiveClick() {
                dialog.dismiss();
                ZHUMainActivity.this.finish();
            }

            @Override
            public void onNegtiveClick() {
                dialog.dismiss();
            }
        });
        dialog.show();
    }
}