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

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Revision as of 08:48, 21 December 2011

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Article Metadata

Compatibility

Platform(s): S60 1st Edition
S60 2nd Edition and FP1, FP2, FP3
S60 3rd Edition and FP1

Article

Created: User:Technical writer 2 (10 May 2007)

Last edited: hamishwillee (21 Dec 2011)

Overview

Applying actions on list box items

Description

Below is a code snippet demonstrating how to apply actions on a list box item selected by the user.
The code to create a simple list box can be obtained from the link below:
[[How to create a simple listbox
It]] is possible to apply any actions (e.g., displaying a popup or a dialog) by catching key events for a list box that currently has keyboard focus. This is done in the OfferKeyEventL() function of the container class that owns the list box.

Solution

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;
        }

Also make sure to add this line

AddToStackL( iAppView );

in AppUi's ConstructL() to add the view/container to the control stack and receive OfferKeyEventL() calls.

@@ Line 1: / Line 1: @@
+[[Category:Technical Solution]][[Category:Symbian C++]][[Category:UI]][[Category:S60 1st Edition]][[Category:S60 2nd Edition]][[Category:S60 3rd Edition]][[Category:S60 3rd Edition, Feature Pack 1]]
 {{KBTS}}
 __NOTOC__
 __NOEDITSECTION__
-[[Category:Technical Solution]]
 {{ArticleMetaData
@@ Line 9: / Line 10: @@
 |platform=S60 1st Edition<br>S60 2nd Edition and FP1, FP2, FP3<br>S60 3rd Edition and FP1
 |devices=
-|category=Symbian C<nowiki>++</nowiki>
+|creationdate=20070510
-|subcategory=UI, UI components
-|creationdate=May 10, 2007
 |keywords=
@@ Line 30: / Line 29: @@
 == Solution ==
-&nbsp;&nbsp;&nbsp;&nbsp;TKeyResponse CMyExampleAppView::OfferKeyEventL(const TKeyEvent& aKeyEvent, TEventCode aType)<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>{</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(aType != EEventKey)<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>{</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return EKeyWasNotConsumed;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>}</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;switch(aKeyEvent.iCode)<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>{</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case EKeyUpArrow:<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case EKeyDownArrow:<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>{</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// Forward up and down key press events to the list box<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return iListBox-<nowiki>></nowiki>OfferKeyEventL( aKeyEvent, aType );<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>}</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;case EKeyOK: // display an information note when item is selected<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>{</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_LIT(KFormatMessage, "Selected item: %d");<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TInt idx = iListBox-<nowiki>></nowiki>CurrentItemIndex();<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TBuf<nowiki><</nowiki>32<nowiki>></nowiki> message;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;message.Format(KFormatMessage, idx);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CAknInformationNote* Note = new (ELeave) CAknInformationNote;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Note-<nowiki>></nowiki>ExecuteLD(message);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return EKeyWasConsumed;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>}</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;default:<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>}</nowiki><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return EKeyWasNotConsumed;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<nowiki>}</nowiki><br>Also make sure to add this line<br>&nbsp;&nbsp;&nbsp;&nbsp;AddToStackL( iAppView ); <br>in AppUi<nowiki>’</nowiki>s ConstructL() to add the view/container to the control stack and receive OfferKeyEventL() calls.
+<code cpp>
+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;
+        }
+</code>
-[[Category:Symbian C++]][[Category:UI]][[Category:S60 1st Edition]] [[Category:S60 2nd Edition]] [[Category:S60 3rd Edition]] [[Category:S60 3rd Edition, Feature Pack 1]]
+Also make sure to add this line
+<code cpp>AddToStackL( iAppView );</code>
+in AppUi's {{Icode|ConstructL()}} to add the view/container to the control stack and receive {{Icode|OfferKeyEventL()}} calls.

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