如何在列表框项中响应动作

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文章信息

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兼容于

平台: S60 1st Edition, S60 2nd Edition and FP1, FP2, FP3, S60 3rd Edition and FP1

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文章

翻译:

翻译自: Archived:Applying actions on list box items using Symbian C++

由 huwell

最后由 hamishwillee 在 08 Aug 2012 编辑

描述

下面的代码示例演示了如何响应用户选定的列表框项。

这里介绍一下如何生成一个简单列表框 How to create a simple listbox in Symbian C++

我们可以捕捉任何键盘事件借以产生各种响应（如弹出一个对话框），我们可以通过OfferKeyEventL()方法来处理

解决方案

TKeyResponse CMyExampleAppView::OfferKeyEventL(const TKeyEvent& aKeyEvent, TEventCode aType)
{
        if(aType != EEventKey)
            {
            return EKeyWasNotConsumed;
            }
        switch(aKeyEvent.iCode)
            {
            case EKeyUpArrow:
            case EKeyDownArrow:
                {
                // Forward up and down key press events to the list box
                return iListBox->OfferKeyEventL( aKeyEvent, aType );
                }
            case EKeyOK: // display an information note when item is selected
                {
                _LIT(KFormatMessage, "Selected item: %d");
                TInt idx = iListBox->CurrentItemIndex();
                TBuf<32> message;
                message.Format(KFormatMessage, idx);
                CAknInformationNote* Note = new (ELeave) CAknInformationNote;
                Note->ExecuteLD(message); 
                return EKeyWasConsumed;
                }
            default:
                break;
            }
        return EKeyWasNotConsumed;
        }

注意要加上这行代码：

    AddToStackL( iAppView );

在AppUi的构造函数ConstructL()中，要将该view/container添加到control stack中以便接收OfferKeyEventL()调用

响应list box的选择事件通常使用list box的观察器MEikListBoxObserver来实现:

class CYourContainer : public CCoeControl,public MEikListBoxObserver
{
public:
   ............
 
   void HandleListBoxEventL(CEikListBox* aListBox, TListBoxEvent aEventType);
   ............
};
 
void CYourContainer ::HandleListBoxEventL( CEikListBox* aListBox, TListBoxEvent aEventType )
{
	TInt index = aListBox->CurrentItemIndex();
	if(  index < 0 )
		return;
 
	if( aEventType == MEikListBoxObserver::EEventEnterKeyPressed )
	{
                _LIT(KFormatMessage, "Selected item: %d");
                TBuf<32> message;
                message.Format(KFormatMessage, index );
                CAknInformationNote* Note = new (ELeave) CAknInformationNote;
                Note->ExecuteLD(message); 
	}
}