surfaceView+MediaPlayer的问题

1.黑屏原因:可能是由于surfaceView还没有创建完成就播放,肯定不行,所以必须在surfaceViewCreated里面才能播放

2.黑屏的第二个原因:activity被用户强制性关闭,或者是界面,下次进来如果是  保存原来的状态,那么可能会黑屏,播放的起点也必须放在surfaceViewCreate里面,只能从这里恢复播放,同时activity强制性退出的时候,需要在surfaceDestroyed把position记录下来,同时如果mediaPlayer是正在播放,需要暂停

 public void surfaceDestroyed(SurfaceHolder holder) {  if(mediaPlayer.isPlaying()){                 position = mediaPlayer.getCurrentPosition();                 mediaPlayer.stop();             }

3.播放完毕之后,改变surfaceView的背景图片是  sv.setBackgroundResource(R.drawable.bg_finish); //改变SurfaceView的背景图片

4.卡顿问题之一,卡顿是超级严重的问题:如果是prepare那里报错的话,那么请把mp.start();方法放在监听事件里面,也就是onPrepare方法里面,这个位置就是你还没有准备好,怎么能够播放呢?在没有准备好之前,可以设置他在不停的加载把

5.播放失败,或者直接闪屏的原因之一:就是从一个视频activity或者view到另外一个视频view的播放,如果时间比较紧凑,可能会立即失败,或者闪退,这里面的原因就是 mediaPlayer还没有来得及释放,也有可能是surfaceView还没有完成销毁,总之存在两个对象,肯定就失败了,有人说这个原始Android设备的问题,如果这个设备使用的操作系统把第三方厂商给修改了,可能会出现这个元,如果是原生态的可能就不会,解决方法就是 第二个视频延迟播放,或者跳转的时候稍微延迟,或者在播放视频的时候弹出正在加载,让那个进度条延迟一秒的旋转时间,再播放,应该可以解决这个问题【http://doublekj.blog.163.com/blog/static/146818474201272453250354/】

  1. private Runnable runner = new Runnable()  
  2.     {  
  3. @Override
  4. public void run()  
  5.         {  
  6.             handler.sendEmptyMessageDelayed(0, 2000);  
  7.         }  
  8.     }; 

6.要注意多次reset的时候,会消耗一部分时间,也即是mediaPlayer播放时间,

7.mediaPlayer如果多次销毁,又多次创建,可能也会每次都去分配一定的空间,代价也是蛮大的,但是安全,不会出现为null的情况

8.这个时候如果是播放同一个视频,这里也会造成卡顿的原因

9.关于声音问题,要在设置数据源之后执行比较好:

把 mPlayer.setAudioStreamType(AudioManager.STREAM_SYSTEM); 换成 mPlayer.setAudioStreamType(AudioManager.STREAM_ALARM);  或者 mediaPlayer.setAudioStreamType(AudioManager.STREAM_VOICE_CALL);//听筒模式

mediaPlayer 的方法是:

Valid and invalid states

Method Name

Valid Sates

Invalid States

Comments

attachAuxEffect

{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Idle, Error}

This method must be called after setDataSource. Calling it does not change the object state.

getAudioSessionId

any

{}

This method can be called in any state and calling it does not change the object state.

getCurrentPosition

{Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

getDuration

{Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Idle, Initialized, Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

getVideoHeight

{Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

getVideoWidth

{Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

isPlaying

{Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

pause

{Started, Paused}

{Idle, Initialized, Prepared, Stopped, PlaybackCompleted, Error}

Successful invoke of this method in a valid state transfers the object to the Paused state. Calling this method in an invalid state transfers the object to the Error state.

prepare

{Initialized, Stopped}

{Idle, Prepared, Started, Paused, PlaybackCompleted, Error}

Successful invoke of this method in a valid state transfers the object to the Prepared state. Calling this method in an invalid state throws an IllegalStateException.

prepareAsync

{Initialized, Stopped}

{Idle, Prepared, Started, Paused, PlaybackCompleted, Error}

Successful invoke of this method in a valid state transfers the object to the Preparing state. Calling this method in an invalid state throws an IllegalStateException.

release

any

{}

After release(), the object is no longer available.

reset

{Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted, Error}

{}

After reset(), the object is like being just created.

seekTo

{Prepared, Started, Paused, PlaybackCompleted}

{Idle, Initialized, Stopped, Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

setAudioSessionId

{Idle}

{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted, Error}

This method must be called in idle state as the audio session ID must be known before calling setDataSource. Calling it does not change the object state.

setAudioStreamType

{Idle, Initialized, Stopped, Prepared, Started, Paused, PlaybackCompleted}

{Error}

Successful invoke of this method does not change the state. In order for the target audio stream type to become effective, this method must be called before prepare() or prepareAsync().

setAuxEffectSendLevel

any

{}

Calling this method does not change the object state.

setDataSource

{Idle}

{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted, Error}

Successful invoke of this method in a valid state transfers the object to the Initialized state. Calling this method in an invalid state throws an IllegalStateException.

setDisplay

any

{}

This method can be called in any state and calling it does not change the object state.

setSurface

any

{}

This method can be called in any state and calling it does not change the object state.

setVideoScalingMode

{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted}

{Idle, Error}

Successful invoke of this method does not change the state.

setLooping

{Idle, Initialized, Stopped, Prepared, Started, Paused, PlaybackCompleted}

{Error}

Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to the Error state.

isLooping

any

{}

This method can be called in any state and calling it does not change the object state.

setOnBufferingUpdateListener

any

{}

This method can be called in any state and calling it does not change the object state.

setOnCompletionListener

any

{}

This method can be called in any state and calling it does not change the object state.

setOnErrorListener

any

{}

This method can be called in any state and calling it does not change the object state.

setOnPreparedListener

any

{}

This method can be called in any state and calling it does not change the object state.

setOnSeekCompleteListener

any

{}

This method can be called in any state and calling it does not change the object state.

setScreenOnWhilePlaying

any

{}

This method can be called in any state and calling it does not change the object state.

setVolume

{Idle, Initialized, Stopped, Prepared, Started, Paused, PlaybackCompleted}

{Error}

Successful invoke of this method does not change the state.

setWakeMode

any

{}

This method can be called in any state and calling it does not change the object state.

start

{Prepared, Started, Paused, PlaybackCompleted}

{Idle, Initialized, Stopped, Error}

Successful invoke of this method in a valid state transfers the object to the Started state. Calling this method in an invalid state transfers the object to the Error state.

stop

{Prepared, Started, Stopped, Paused, PlaybackCompleted}

{Idle, Initialized, Error}

Successful invoke of this method in a valid state transfers the object to the Stopped state. Calling this method in an invalid state transfers the object to the Error state.

getTrackInfo

{Prepared, Started, Stopped, Paused, PlaybackCompleted}

{Idle, Initialized, Error}

Successful invoke of this method does not change the state.

addTimedTextSource

{Prepared, Started, Stopped, Paused, PlaybackCompleted}

{Idle, Initialized, Error}

Successful invoke of this method does not change the state.

selectTrack

{Prepared, Started, Stopped, Paused, PlaybackCompleted}

{Idle, Initialized, Error}

Successful invoke of this method does not change the state.

deselectTrack

{Prepared, Started, Stopped, Paused, PlaybackCompleted}

{Idle, Initialized, Error}

Successful invoke of this method does not change the state.

surfaceView的相关概念:

MediaPlayer主要用于播放音频,它是没有提供输出图像的输出界面,这时我们就用到了SurfaceView控件,将它与MediaPlayer结合起来,就能达到了视频的输出了。首先来了SurfaceView这个控件类

SurfaceView类

构造方法

方法名称

描述

public SurfaceView(Context context)

通过Context创建SurfaceView对象

public SurfaceView(Context context, AttributeSet attrs)

通过Context对象和AttributeSet创建SurfaceView对象

public SurfaceView(Context context, AttributeSet attrs, int defStyle)

通过Context对象和AttributeSet创建并可以指定样式,SurfaceView对象

常用方法

方法名称

描述

public SurfaceHolder getHolder ()

得到SurfaceHolder对象用于管理SurfaceView

public void setVisibility (int visibility)

设置是否可见,其值可以是VISIBLE, INVISIBLE, GONE.

SurfaceHolder

它是一个接口,用于管理SurfaceView。里面有两个常用的内部接口SurfaceHolder.Callback,SurfaceHolder.Callback2而Callback2是实现于Callback的

常用方法

方法名称

描述

public abstract void addCallback (SurfaceHolder.Callback callback)

添加一个Callback对象监听SurfaceView的变化

public abstract void removeCallback (SurfaceHolder.Callback callback)

移除Callback

public abstract void setType (int type)

设置SurfaceView的控制方式

public abstract Canvas lockCanvas ()

锁定整个SurfaceView对象,获取该Surface上的Canvas

public abstract Canvas lockCanvas (Rect dirty)

锁定SurfaceView上Rect划分的区域,获取该Surface上的Canvas

public abstract void unlockCanvasAndPost (Canvas canvas)

调用该方法,之前所绘制的图形还处于缓冲之中,下一次的lockCanvas()方法锁定的区域可能会“遮挡”它

SurfaceHolder.CallBack

在Callback里有三个抽象方法

方法名称

描述

public abstract void surfaceChanged (SurfaceHolder holder, int format, int width, int height)

SurfaceView改变时触发

public abstract void surfaceCreated (SurfaceHolder holder)

SurfaceView创建时触发

public abstract void surfaceDestroyed (SurfaceHolder holder)

SurfaceView销毁时触发

如何理解这几个类或者接口之间的关系?

这样理解:

SurfaceView它用于显示,SurfaceHolder就是用于用来管理这个显示的SurfaceView对象的,但在SurfaceHolder是怎么样去管理这个对象的呢?这就用到了SurfceHolder.addCallback()方法添加一个SurfaceHolder接口的内部接口的三个抽象方法用于管理或者说是用于监听SurfaceView。这样就达到了管理SurfaceView的目的。

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