[Symbian项目进展]怎样在S60指示面板上画图标，原代码+示意图

当在系统设置中设置了“实时监控”，此时手机画面的指示面板上应该出现一个图标，表明有程序在后台运行。
本文就是探讨怎样在S60指示面板上画图标。为了在电源面板附近显示图标，你必须要作相应的编码。

我写了一个CIndicatorIcon的类，它继承自CCoeControl。
二次构造函数ConstructL()代码如下：

void CIndicatorIcon::ConstructL()
        {
        iMyWindowGroup = RWindowGroup(iCoeEnv->WsSession());
        User::LeaveIfError(iMyWindowGroup.Construct((TUint32)&iMyWindowGroup));

        iMyWindowGroup.SetOrdinalPosition(0, ECoeWinPriorityAlwaysAtFront);
        iMyWindowGroup.EnableReceiptOfFocus(EFalse);

        CreateWindowL(&iMyWindowGroup);

        // by default setting the indicator icon to inactive
        SetIndicatorIconL(EIndicatorIconAppActive);

        ActivateL();
        }

注意，RWindowGroup需要W32std.h头文件，连接时需要添加Ws32.lib。
在构造函数中，调用另外一个函数SetIndicatorIconL()来设置图标：

void CIndicatorIcon::SetIndicatorIconL(TIndicatorIcon aIndicatorIconType, TBool aRedraw)
        {
        switch(aIndicatorIconType)
                {
                case EIndicatorIconEmpty:
                        iIndicator = CEikonEnv::Static()->CreateBitmapL(KSysIconFile, EMbmAvkonQgn_prop_empty);
                        iIndicatorMask = CEikonEnv::Static()->CreateBitmapL(KSysIconFile, EMbmAvkonQgn_prop_empty_mask);
                        break;

                case EIndicatorIconAppActive:
                        iIndicator = CEikonEnv::Static()->CreateBitmapL(KSysIconFile, EMbmAvkonQgn_bt_connect_on);
                        iIndicatorMask = CEikonEnv::Static()->CreateBitmapL(KSysIconFile, EMbmAvkonQgn_bt_connect_on_mask);
                        break;

                case EIndicatorIconAppInactive:
                        iIndicator = CEikonEnv::Static()->CreateBitmapL(KSysIconFile, EMbmAvkonQgn_prop_bt_audio);
                        iIndicatorMask = CEikonEnv::Static()->CreateBitmapL(KSysIconFile, EMbmAvkonQgn_prop_bt_audio_mask);
                        break;

                default:
                        break;
                }

        SetRect(TRect(TPoint(KIndicatorPosX, KIndicatorPosY),iIndicator->SizeInPixels()));
        
        // if aRedraw == ETrue just draw the canvas again.
        if(aRedraw)
                {
                DrawNow();
                }
        }

上面把指示面板需要显示的图标设置好了，但是必须要重载CCoeControl的Draw()函数来显示这个图标，Draw()代码如下：



void CIndicatorIcon::Draw(const TRect& aRect) const
        {
        CWindowGc& gc = SystemGc();

        gc.Clear();
        gc.SetBrushStyle(CGraphicsContext::ENullBrush);
        gc.BitBltMasked(TPoint(aRect.iTl.iX, aRect.iTl.iY), 
                iIndicator, 
                TRect(TPoint(0, 0), iIndicator->SizeInPixels()), 
                iIndicatorMask, 
                ETrue);
        }

最后在AppUi类的构造函数中添加如下两行代码：
        iIndicatorIcon = CIndicatorIcon::NewL();
        // The next line will set the icon to draw and it'll draw to the screen.
        iIndicatorIcon->SetIndicatorIconL(CIndicatorIcon::EIndicatorIconAppInactive, ETrue);

效果图如下：

 

Indicator icon when application is running in the foreground.		Indicator icon when application is running in the background..
Indicator icon when application is running in the background with the task view..

你可以在这里下载示例程序的源代码：

Sample code for showing icon on the IndicatorPane