在没有ui的程序中捕获所有的key事件

CKeyCapturer2演示了如何在那些没有实现标准程序框架的程序中捕获key事件。在实现了标准程序框架的程序中你可以通过调用OfferKeyEventL来捕捉.

原文： http://wiki.forum.nokia.com/index.php/Capturing_all_keys_in_Non-GUI_applications

CKeyCapturer2* CKeyCapturer2::NewL(MKeyCallBack& aObserver)
    ...{
    CKeyCapturer2* self = CKeyCapturer2::NewLC(aObserver);
    CleanupStack::Pop(self);
    return self;
    }
 
CKeyCapturer2* CKeyCapturer2::NewLC(MKeyCallBack& aObserver)
    ...{
    CKeyCapturer2* self = new (ELeave) CKeyCapturer2(aObserver);
    CleanupStack::PushL(self);
    self->ConstructL();
    return self;
    }
 
 
CKeyCapturer2::CKeyCapturer2(MKeyCallBack& aObserver)
:CActive(EPriorityHigh),iObserver(aObserver)
...{
    
}
 
CKeyCapturer2::~CKeyCapturer2()
...{
    Cancel();
    iWg.Close();
    iWsSession.Close();
}
 
void CKeyCapturer2::ConstructL()
...{
    User::LeaveIfError(iWsSession.Connect());
 
    CActiveScheduler::Add(this);
 
    iWg=RWindowGroup(iWsSession);
    User::LeaveIfError(iWg.Construct((TUint32)&iWg, EFalse));
    
    iWg.SetOrdinalPosition(1, ECoeWinPriorityAlwaysAtFront+2);
    iWg.EnableReceiptOfFocus(ETrue);
 
    CApaWindowGroupName* wn=CApaWindowGroupName::NewLC(iWsSession);
    wn->SetHidden(EFalse);
    wn->SetWindowGroupName(iWg);
    CleanupStack::PopAndDestroy();
 
    Listen();
}
 
void CKeyCapturer2::RunL()
...{
    if (iStatus == KErrNone) 
    ...{
        TWsEvent e;
        iWsSession.GetEvent(e);
        TInt type = e.Type();
 
        switch (type)
        ...{
        case EEventKey:    
            if(iObserver.KeyCapturedL(e))
            ...{
                TInt wgId = iWsSession.GetFocusWindowGroup();
                iWsSession.SendEventToWindowGroup(wgId, e);
            }
            break;
        case EEventKeyUp:
        case EEventKeyDown:
            break;
        };
    }
    
    if (iStatus != KErrCancel) 
    ...{
        Listen();
    }
}
 
void CKeyCapturer2::DoCancel()
...{
    iWsSession.EventReadyCancel();
}
 
 
void CKeyCapturer2::Listen()
...{
    iWsSession.EventReady(&iStatus);
    SetActive();
}[edit] CapturingKeys2.h 
class MKeyCallBack 
...{
public:
    virtual TBool KeyCapturedL(TWsEvent aEvent) = 0;
};
 
 
 
class CKeyCapturer2 : public CActive 
...{
public:
    static CKeyCapturer2* NewL(MKeyCallBack& aObserver);
    static CKeyCapturer2* NewLC(MKeyCallBack& aObserver);
    virtual ~CKeyCapturer2();
private:
    CKeyCapturer2(MKeyCallBack& aObserver);
    void ConstructL();
    void RunL();
    void DoCancel();
    void Listen();
private:
    MKeyCallBack&     iObserver;
    RWsSession         iWsSession;
    RWindowGroup    iWg; 
};