状态变化监听器MediaPlayer的 [英] State change listener for MediaPlayer

问题描述

在此图中有不少状态的：

但标准听众我可以听只是一些基本状态。

but with standard listener I can listen just some basic states.

所以可以监听MediaPlayer的每状态的变化？

So is possible to listen every states changes for MediaPlayer?

推荐答案

不幸的是我没有发现比MediaPlayer的使用自定义的状态机容器周围做这个的其他方式。

Unfortunately I found no way of doing this other than surrounding the MediaPlayer with a custom state machine container.

新增...

您可以创建一个容器，是一个独立的，并定义了它自己的状态。并与MediaPlayer的唯一交互是通过这个容器完成。所有其它类需要访问容器的API。

You could create a container that is a singleton and defines it's own states. And the only interaction with the MediaPlayer is done through this container. All other classes need to access the API of the container.

下面是一个简单概述：

public class MyContainer implements OnBufferingUpdateListener, 
                                            OnCompletionListener, 
                                            OnErrorListener,  
                                            OnInfoListener, 
                                            OnPreparedListener 
{
    static enum MP_STATES
    {
        MPS_IDLE,
        MPS_INITIALIZED,
        MPS_PREPARING,
        MPS_PREPARED,
        MPS_STARTED,
        MPS_STOPPED,
        MPS_PAUSED,
        MPS_PLAYBACK_COMPLETED,
        MPS_ERROR,
        MPS_END,
    }

    private static MyContainer s_mpm = null;
    private MP_STATES m_eState;
    private MediaPlayer m_mp;

    public static MyContainer get()
    {
        if (null == s_mpm)
        {
            s_mpm = new MyContainer();          
        }
        return s_mpm;
    }

    private MyContainer()
    {       
        m_mp = new MediaPlayer();
        m_mp.setOnBufferingUpdateListener(this);
        m_mp.setOnCompletionListener(this);
        m_mp.setOnErrorListener(this);
        m_mp.setOnInfoListener(this);
        m_mp.setOnPreparedListener(this);

        m_eState = MP_STATES.MPS_IDLE;
    }

    public MP_STATES getState()
    {
        return m_eState;
    }

    public void setUrl(String szUrl)
    {
        bringToIdleState();

        try {
            m_mp.setDataSource(szUrl);
            m_eState = MP_STATES.MPS_INITIALIZED;
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        m_mp.prepareAsync();
        m_eState = MP_STATES.MPS_PREPARING;
    }

    public void play()
    {
        switch (m_eState)
        {
            case MPS_PREPARED:
            case MPS_PAUSED:
                m_mp.start();
                m_eState = MP_STATES.MPS_STARTED;
                break;
            default:
                // !! throw exception
        }       
    }

    public void pause()
    {
        switch (m_eState)
        {
            case MPS_STARTED:
                m_mp.pause();
                m_eState = MP_STATES.MPS_PAUSED;
                break;
            default:
                // !! throw exception
        }       
    }

    public void release() 
    {
        m_mp.release();
        m_mp = null;
    }

    private void bringToIdleState()
    {
        // reset() should bring MP to IDLE
        m_mp.reset();
        m_eState = MP_STATES.MPS_IDLE;      
    }   

    // ** Callbacks

    @Override
    public void onPrepared(MediaPlayer mp) 
    {
        m_eState = MP_STATES.MPS_PREPARED;    
        m_mp.start();
        m_eState = MP_STATES.MPS_STARTED;           
    }

    @Override
    public boolean onInfo(MediaPlayer mp, int what, int extra) 
    {
        return false;
    }

    @Override
    public boolean onError(MediaPlayer mp, int what, int extra) 
    {
        m_eState = MP_STATES.MPS_IDLE;
        return false;
    }

    @Override
    public void onCompletion(MediaPlayer mp) 
    {
          // play the next song
    }

    @Override
    public void onBufferingUpdate(MediaPlayer mp, int percent) 
    {
    }

}

}

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