实现MediaPlay的基本步骤是

1. 创建MediaPlay对象

2. 调用setDataSource对象这是音频文件路径

3. 调用prepare加载音频

4. 调用start开始播放

5. 调用pause暂停

6. 调用stop停止播放

而MediaPlay也有其他方法

• getCurrentPosition，获得当前播放位置

• getDuration，获得播放时长

• isPlay，判断是否处于播放状态

• release，释放资源

• reset，回到最初的状态

• seekTo，设置播放位置

• setVolume，设置音量

    private  MediaPlayer mediaPlayer=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mediaPlayer=new MediaPlayer();
        if(ContextCompat.checkSelfPermission(this,
                Manifest.permission.READ_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},1);
        }else{
            initMediaPlayer();
        }
        Button btPlayMp3= (Button) findViewById(R.id.btPlayMp3);
        btPlayMp3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(!mediaPlayer.isPlaying()){
                    mediaPlayer.start();
                }
            }
        });
        Button btPauseMp3= (Button) findViewById(R.id.btPauseMp3);
        btPauseMp3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(mediaPlayer.isPlaying()){
                    mediaPlayer.pause();
                }
            }
        });
        Button btStopMp3= (Button) findViewById(R.id.btStopMp3);
        btStopMp3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(mediaPlayer.isPlaying()){
                    mediaPlayer.stop();
                    try {
                        mediaPlayer.prepare();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        });
    }
    private void initMediaPlayer(){
        try {
            File file=new File(Environment.getExternalStorageDirectory()+"/music","honor.mp3");
            mediaPlayer.setDataSource(file.getPath());
            mediaPlayer.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if(requestCode==1){
            if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED){
                initMediaPlayer();
            }else{
                Toast.makeText(this,"未获得SD卡访问权限",Toast.LENGTH_LONG).show();
                finish();
            }
        }
    }
    @Override
    protected void onDestroy() {
        if(mediaPlayer!=null){
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer=null;
        }
        super.onDestroy();
    }