Symbian (console DrawText)后台程序如何在桌面上绘制文本效果

Symbian 后台程序如何在桌面上绘制文本效果

大家用过来电通的朋友都会知道.
当来电或者去电的时候.桌面上会有地区号码的文字显示.
那这种效果应该如何实现呢.
其实非常的简单,让我们今天来看看这种效果是如何实现的.
小弟最近也仿写了一个字样的效果,自我感觉还是不错的.
特在此总结一下为自己留个脚印没准其他网友也用得着.
哈哈少费话了进入正题了.

//初始化窗口
void CWindowDrawer::ConstructL(const TDesC& aArea)
{
 

   CActiveScheduler::Add(this);
 
    User::LeaveIfError(iWsSession.Connect());
 
    iScreenDevice=new (ELeave) CWsScreenDevice(iWsSession);
    User::LeaveIfError(iScreenDevice->Construct());
    User::LeaveIfError(iScreenDevice->CreateContext(iWindowGc));
 
    TFontSpec MyeFontSpec (KFontArial, 12*15);   
    MyeFontSpec.iTypeface.SetIsProportional(ETrue);
    User::LeaveIfError(iScreenDevice->GetNearestFontInTwips(iMyFont,MyeFontSpec));
 
    iWindowGroup=RWindowGroup(iWsSession);
    User::LeaveIfError(iWindowGroup.Construct((TUint32)&iWindowGroup, EFalse));
//    iWindowGroup.SetOrdinalPosition(0,ECoeWinPriorityNormal);
    iWindowGroup.SetOrdinalPosition(0,ECoeWinPriorityAlwaysAtFront);
    iWindowGroup.EnableReceiptOfFocus(EFalse);
 
    CApaWindowGroupName* winGroupName=CApaWindowGroupName::NewLC(iWsSession);
    winGroupName->SetHidden(ETrue);
    winGroupName->SetWindowGroupName(iWindowGroup);
    CleanupStack::PopAndDestroy();
 
    iWindow=RWindow(iWsSession);
    User::LeaveIfError(iWindow.Construct(iWindowGroup, (TUint32)&iWindow));
 
    TPixelsTwipsAndRotation SizeAndRotation;
    iScreenDevice->GetDefaultScreenSizeAndRotation(SizeAndRotation);
 
    iWindow.Activate();
    //iWindow.SetExtent(TPoint(0,0),SizeAndRotation.iPixelSize);
    iWindow.SetExtent(TPoint(0,0),TSize(240,40));
    iWindow.SetBackgroundColor(KRgbBlue);
//    iWindow.SetOrdinalPosition(0,ECoeWinPriorityNormal);
    iWindow.SetOrdinalPosition(0, ECoeWinPriorityAlwaysAtFront);
    iWindow.SetNonFading(ETrue);   
    iWindow.SetVisible(ETrue);       
   
    SetWhere(aArea);
    Draw();
    iWsSession.RedrawReady(&iStatus);
    SetActive();
}

//监听到绘制消息后,绘制字符串
void CWindowDrawer::RunL()
{
    if (iStatus != KErrCancel)
    {
        TWsRedrawEvent e;
        iWsSession.GetRedraw(e);
 
        // if Windows Server does not want a redraw the window handle is 0
        if (e.Handle() != 0)
            {
            // draw our only window
            Draw();
            }
 
        iWsSession.RedrawReady(&iStatus);
        SetActive();
    }
}

//绘制字符串

void CWindowDrawer::Draw()
{
    iWindowGc->Activate(iWindow);
 
    TRect DrwRect(TPoint(0,0), iWindow.Size());
 
    iWindow.Invalidate(DrwRect);
    iWindow.BeginRedraw();
    iWindowGc->Clear(DrwRect);
 
    if(iMyFont)
    {
        iWindowGc->UseFont(iMyFont);
 
        TInt StartY ((DrwRect.Height() - iMyFont->HeightInPixels()) / 2);
       
        iWindowGc->SetPenColor(TRgb(255,0,0));       
        if(iWhereArea != NULL)
            {
            iWindowGc->DrawText(iWhereArea->Des(),TRect(0,StartY,DrwRect.Width

(),(StartY + iMyFont->HeightInPixels())),iMyFont->AscentInPixels(),

CGraphicsContext::ECenter, 0);   
            }
        else
            {
            iWindowGc->DrawText(_L("/x672A/x77E5/x7535/x8BDD"),TRect

(0,StartY,DrwRect.Width(),(StartY + iMyFont->HeightInPixels())),iMyFont->AscentInPixels(),

CGraphicsContext::ECenter, 0);
            }
    }
 
    iWindow.EndRedraw();
 
    iWindowGc->Deactivate();
    iWsSession.Flush();
}

以上代码在N73/N95/6120c上测试通过