Switching views on Symbian
Article Metadata
Tested with
Compatibility
S60 5th Edition
Platform Security
Article
Contents |
Overview
This snippet demonstrates how to switch views. The snippet uses the Avkon View-Switching Architecture class CAknView.
When and why do we need views?
- When your application has multiple screens that form complex navigational paths.
- When you want to save data on every view switching, to update the model with the newly entered or updated data.
- When you want to send data from one screen to another or to external applications.
- CAknView handles menu-commands, switching of views, sending keyboard/pointer events to the respective container class.
- Simple applications don't need views that are derived from CAknView.
The S60 view architecture is used in application development in the S60 platform. Each view has its own control stack. The view architecture uses the base class CAknViewAppUi for the UI controller. The UI controller manages one or more CAknView derived views. The view class uses CCoeControl-derived container control.
MMP file
The following libraries and capabilities are required:
CAPABILITY None
LIBRARY avkon.lib
LIBRARY eikcore.lib
LIBTATY eiksrv.lib
Header file
#include <aknview.h>
#include <aknviewappui.h>
Source file
Application app UI class CAknViewAppUi creates the default view on its construction.
void CSomeAppUi::ContructL()
{
BaseConstructL(EAknEnableSkin);
// Create your view derived from CAknView
iMyView = CMyView::NewL();
// Add view into control stack
AddViewL(iMyView);
// Use this as a default view
SetDefaultViewL(*iMyView);
}
CAknView activates the control of the view. DoActivateL() is called by the View Server when a client requests that your view is activated.
void CSomeView::DoActivateL(const TVwsViewId& aPrevViewId,
TUid aCustomMessageId,
const TDesC8& aCustomMessage)
{
if (iSomeControl == NULL)
{
// Create control for the view
iSomeControl = CSomeContainer::NewL(ClientRect());
// Add it to control stack
AppUi()->AddToStackL(*this, iSomeControl);
}
}
void CSomeView::DoDeactivate()
{
if (iSomeControl != NULL)
{
// Remove view from the control stack
AppUi()->RemoveFromViewStack(*this, iSomeControl);
// Delete view
delete iSomeControl;
iSomeControl = NULL;
}
}
To switch to a view within your application, you can use the AppUi class method ActivateLocalViewL(). The new view is activated first, and the previous view is deactivated after that.
const TUid KSomeViewId = { 1 }; // UID of the some view
ActivateLocalViewL(KSomeViewId); // activate some view
Postconditions
Views can be activated and switched.
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