Enabling drag events in Symbian C++ on touch-enabled devices
Article Metadata
Tested with
Devices(s): Nokia 5800 XpressMusic
Compatibility
Platform(s): S60 5th Edition
Article
Keywords: CCoeControl::EnableDragEvents()
Created: tepaa
(03 Oct 2008)
Last edited: hamishwillee
(14 Jun 2012)
Contents |
Overview
S60 5th Edition supports touch events. All AVKON UI controls handle touch UI events and you do not need to implement anything new.
If you want to listen for drag events in your custom CCoeControl UI control, use CCoeControl::EnableDragEvents().
MMP file
The following libraries are required:
LIBRARY cone.lib
Header file
private:
void ConstructL(const TRect& aRect);
void HandlePointerEventL(const TPointerEvent& aPointerEvent);
void Move(const TPoint& aPoint);
private:
TPoint iMovePoint;
Source file
Enable drag event listening in the container control ConstructL().
EnableDragEvents() needs to be called only once in the entire application.
void CMyControl::ConstructL(const TRect& /*aRect*/)
{
// Create window of this container control
CreateWindowL();
// Enable drag events listening
EnableDragEvents();
// ...
Drag events are received.
void CMyControl::HandlePointerEventL(const TPointerEvent& aPointerEvent)
{
if (aPointerEvent.iType == TPointerEvent::EButton1Down)
{
iMovePoint = aPointerEvent.iPosition;
}
else if (aPointerEvent.iType == TPointerEvent::EDrag)
{
// Drag events received, what to do with it?
// We could move this control...
Move(aPointerEvent.iPosition);
// Store current point
iMovePoint = aPointerEvent.iPosition;
// Draw this control again because we move to position of it
DrawNow();
}
// ...
Moving control to dragging point:
void CMyControl::Move(const TPoint& aPoint)
{
TPoint offset;
// Calculate moving offset
offset.iX = aPoint.iX - iMovePoint.iX;
offset.iY = aPoint.iY - iMovePoint.iY;
TRect rect = Rect();
// Move this control
rect.Move(offset);
}
Postconditions
Drag events are received and control is moved to the pointer location.
See also
S60 5th Edition: Solitaire Game Example
S60 Platform: Image Converter Example
