Playing audio files

最新推荐文章于 2025-11-28 17:35:08 发布
转载 最新推荐文章于 2025-11-28 17:35:08 发布 · 523 阅读 · 0
文章标签：

#audio #delete #class #null #file #ui

本文介绍了一个音频播放器的实现细节，包括播放、停止、设置音量等功能，并通过状态观察者模式来更新播放状态。 
 
AudioPlayer.cpp
#include <Mda/Common/Resource.h>
#include <BAUTILS.H>
  
CAudioPlayer* CAudioPlayer::NewL(MExamplePlayStateObserver& aObserver)
    {
    CAudioPlayer* self = CAudioPlayer::NewLC(aObserver);
    CleanupStack::Pop(self);
    return self;
    }
 
 
CAudioPlayer* CAudioPlayer::NewLC(MExamplePlayStateObserver& aObserver)
    {
    CAudioPlayer* self = new (ELeave) CAudioPlayer(aObserver);
    CleanupStack::PushL(self);
    self->ConstructL();
    return self;
    }
 
 
CAudioPlayer::CAudioPlayer(MExamplePlayStateObserver& aObserver)
:iObserver(aObserver),iVolume(5)
    {
 
    }
 
 
CAudioPlayer::~CAudioPlayer()
{
          delete iExampleTimer;
 
    if(iPlayerUtility)
    {
           iPlayerUtility->Stop();
           iPlayerUtility->Close();
    }
 
    delete iPlayerUtility;
}
 
void CAudioPlayer::ConstructL()
{
          iExampleTimer = CExampleTimer::NewL(CActive::EPriorityStandard,*this);
 
          ReportStateAndTime();
}
 
void CAudioPlayer::TimerExpired(TAny* /*aTimer*/,TInt aError)
{
          // update states first.
          ReportStateAndTime();
 
          if(iExampleTimer && aError != KErrCancel)          
          {
                    iExampleTimer->After(KReFreshTimeOut);
          }
}
 
 
void CAudioPlayer::PlayL(const TDesC& aFileName)
{
          iCurrentFile.iName.Copy(aFileName);
 
          if(iExampleTimer)   
          {
                    iExampleTimer->Cancel();
          }
 
          if(iPlayerUtility)
    {
           iPlayerUtility->Stop(); // stop any play/rec
           iPlayerUtility->Close();// close previously opened file.
    }
 
          delete iPlayerUtility;           // and then we can delete it.
          iPlayerUtility = NULL;
          iPlayerUtility = CMdaAudioRecorderUtility::NewL(*this);
    iPlayerUtility->OpenFileL(iCurrentFile.iName);
 
          if(iExampleTimer)   
          {
                    iExampleTimer->After(KReFreshTimeOut);
          }
}
 
void CAudioPlayer::StopL(void)
{
          if(iExampleTimer)
          {
                    iExampleTimer->Cancel();
          }
 
    if(iPlayerUtility)
    {
           iPlayerUtility->Stop();
    }
 
    ReportStateAndTime();
}
 
void CAudioPlayer::SetVolume(TInt& aVolume)
{
          if(aVolume < 1)
                    aVolume = 1;
          else if(aVolume > 10)
                    aVolume = 10;
 
          iVolume = aVolume;// save to internal value always
          if(iPlayerUtility) // and if utility exists, set it to it as well.
          {
                    TInt Vol = ((iPlayerUtility->MaxVolume() * iVolume) / 10);
                    iPlayerUtility->SetVolume(Vol);
          }
}
 
 
void CAudioPlayer::ReportStateAndTime(void)
{
          TInt CurrPosition(0),FileDuration(0);
 
          CMdaAudioClipUtility::TState CurrState(CMdaAudioClipUtility::ENotReady);
 
          if(iPlayerUtility)
          {
                    CurrState =  iPlayerUtility->State();
 
                    TInt64 HelpPos = iPlayerUtility->Position().Int64();         
                    // micro seconds, thus lets make it seconds for UIs
                    CurrPosition = HelpPos / 1000000;
 
                    // and with playing its the file duration.
                    HelpPos = iPlayerUtility->Duration().Int64();      
                    FileDuration = HelpPos / 1000000;
          }
 
          // update valus to the UI
          iObserver.StateUpdate(CurrState,CurrPosition,FileDuration);
}
 
 
void CAudioPlayer::MoscoStateChangeEvent(CBase* aObject, TInt aPreviousState, TInt aCurrentState, TInt /*aErrorCode*/)
{
          if(aObject == iPlayerUtility)
          {
                    ReportStateAndTime();
 
                    switch(aCurrentState)
                    {
                    case CMdaAudioClipUtility::EOpen:
                               {
                                         // only when first opening files.
                                         // also called with aCurrentState == EOpen, when
                                         // playing or recording finishes.
                                         if(aPreviousState == CMdaAudioClipUtility::ENotReady)
                                         {
                                                   TInt Vol = ((iVolume * iPlayerUtility->MaxVolume()) / 10);
                                                   iPlayerUtility->SetVolume(Vol);
 
                                                   TRAPD(err,iPlayerUtility->PlayL(););
                                         }
                               }
                               break;
                    case CMdaAudioClipUtility::EPlaying:
                    case CMdaAudioClipUtility::ERecording:
                    case CMdaAudioClipUtility::ENotReady:
                    default: // no need to do anything on these states.
                               break;
                    }
          }
}
 
 
AudioPlayer.h 
#include <MdaAudioSampleEditor.h>
#include <Mda/Client/Utility.h>
#include "CExampleTimer.h"
 
const TInt          KReFreshTimeOut = 1000000; // re-fresh every second
//
class MExamplePlayStateObserver
          {
          public:
                    virtual void StateUpdate(CMdaAudioClipUtility::TState aState, TInt aPosition, TInt aDuration)=0;
          };
 
 
class CAudioPlayer : public CBase, public MMdaObjectStateChangeObserver,MExampleTimerNotify
    {
public:
    static CAudioPlayer* NewL(MExamplePlayStateObserver& aObserver);
    static CAudioPlayer* NewLC(MExamplePlayStateObserver& aObserver);
     ~CAudioPlayer();
public:  // public functions 
    void PlayL(const TDesC& aFileName);
          void StopL(void);
          void SetVolume(TInt& aVolume);
protected: // from MMdaObjectStateChangeObserver & MExampleTimerNotify
          void MoscoStateChangeEvent(CBase* aObject, TInt aPreviousState, TInt aCurrentState, TInt aErrorCode);
          void TimerExpired(TAny* aTimer,TInt aError);
private:// interna functions
          void ReportStateAndTime(void);
    void ConstructL();
    CAudioPlayer(MExamplePlayStateObserver& aObserver);       
private:
          MExamplePlayStateObserver&               iObserver;
          CMdaAudioRecorderUtility*                iPlayerUtility;
    TInt                                                                iVolume;
    TMdaFileClipLocation                            iCurrentFile;
    CExampleTimer*                                            iExampleTimer;
};
 
 
PlayUtility.cpp 
#include <MdaAudioTonePlayer.h>
#include <eikmenup.h>
 
 
CPlayerUtility* CPlayerUtility::NewL(const TDesC& aFileName)
{
    CPlayerUtility* self = NewLC(aFileName);
    CleanupStack::Pop(self);  
    return self;
}
 
CPlayerUtility* CPlayerUtility::NewLC(const TDesC& aFileName)
{
    CPlayerUtility* self = new (ELeave) CPlayerUtility();
    CleanupStack::PushL(self);
    self->ConstructL(aFileName);
    return self;
}
 
CPlayerUtility::~CPlayerUtility()
{
          if(iPlayUtility)
          {
                    iPlayUtility->Stop();
                    iPlayUtility->Close();
          }
 
    delete iPlayUtility;
}
 
CPlayerUtility::CPlayerUtility()
{
}
 
void CPlayerUtility::ConstructL(const TDesC& aFileName)
{
    iPlayUtility = CMdaAudioPlayerUtility::NewFilePlayerL(aFileName, *this);
          iPlaying = iPrepared = EFalse;
}
 
void CPlayerUtility::Play()
{
          iPlayUtility->Play();
          iPlaying = ETrue;
}
 
void CPlayerUtility::Stop()
{
          iPlayUtility->Stop();
          iPlaying = EFalse;
}
 
 
void CPlayerUtility::MapcPlayComplete(TInt /*aError*/)
{
          iPlaying = EFalse;
}
 
void CPlayerUtility::MapcInitComplete(TInt aError, const TTimeIntervalMicroSeconds& /*aDuration*/)    
{
          if(aError == KErrNone)
          {
                    iPrepared = ETrue;
                    iPlayUtility->SetVolume(iPlayUtility->MaxVolume());          
                iPlayUtility->Play();
          }
}
 
PlayUtility.h 
#include <e32std.h>
#include <MdaAudioSamplePlayer.h>
 
class CPlayerUtility : public CBase, public MMdaAudioPlayerCallback
    {
public:
    static CPlayerUtility* NewL(const TDesC& aFileName);
    static CPlayerUtility* NewLC(const TDesC& aFileName);
    ~CPlayerUtility();
private:
    CPlayerUtility();
    void ConstructL(const TDesC& aFileName);
public:
    void Play();
    void Stop();
public: // from MMdaAudioToneObserver
          void MapcInitComplete(TInt aError, const TTimeIntervalMicroSeconds& aDuration);
          void MapcPlayComplete(TInt aError);
private:
    CMdaAudioPlayerUtility* iPlayUtility;
    TBool                                           iPlaying,iPrepared;
};
 
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