epoc32/include/mw/aknpointereventsuppressor.h
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:33:34 +0100 (2010-03-31)
branchSymbian3
changeset 4 837f303aceeb
parent 2 2fe1408b6811
permissions -rw-r--r--
Current Symbian^3 public API header files (from PDK 3.0.h)
This is the epoc32/include tree with the "platform" subtrees removed, and
all but a selected few mbg and rsg files removed.
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/*
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* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).
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* All rights reserved.
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* This component and the accompanying materials are made available
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* under the terms of "Eclipse Public License v1.0"
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* which accompanies this distribution, and is available
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* at the URL "http://www.eclipse.org/legal/epl-v10.html".
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*
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* Initial Contributors:
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* Nokia Corporation - initial contribution.
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*
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* Contributors:
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*
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* Description: 
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*
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*/
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#ifndef AKNPOINTEREVENTSUPPRESSOR_H
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#define AKNPOINTEREVENTSUPPRESSOR_H
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//  INCLUDES
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#include <coecntrl.h>
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// CLASS DECLARATION
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/**
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*  Utility class for removing unwanted pointer events, for instance
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*  when distinguishing tap events from intended drags.
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*
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*  Usage pattern, where iSuppressor is a CAknPointerEventSuppressor*:
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*
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*  void CMyControl::HandlePointerEventL(const TPointerEvent& aPointerEvent)
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*  	{
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*  	if (iSuppressor->SuppressPointerEvent(aPointerEvent))
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*  		return;
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*  	
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*  	switch (aPointerEvent.iType)
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*  		{
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*  		case TPointerEvent::EButton1Down:
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*  			iTap = ETrue;
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*  			break;
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*  		case TPointerEvent::EButton1Up:
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*  			if (iTap)
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*  				HandleTapL(aPointerEvent);
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*  			break;
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*  		case TPointerEvent::EDrag:
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*  			iTap = EFalse;
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*  			HandleDragL(aPointerEvent);
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*  			break;
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*  		default:
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*  			break;
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*  		}
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*  	}
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*
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*  @since S60 5.0
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*/
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NONSHARABLE_CLASS(CAknPointerEventSuppressor) : public CBase
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	{
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public:
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	/**
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	* Factory function
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	*
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	* This creates a pointer event suppressor that will suppress
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	* drag events while the pointer interaction may be a tap.
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	*/
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	IMPORT_C static CAknPointerEventSuppressor* NewL();
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    /**
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    * Destructor.
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    */    
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	IMPORT_C ~CAknPointerEventSuppressor();
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	/**
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	* Tests whether a pointer event should be suppressed.
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	*
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	* A control that wants pointer event suppression should feed
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	* all pointer events to this function. It will return ETrue if
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	* the pointer event should be ignored by the control.
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	* Only controls that have unrelated behaviour on tap and drag
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	* actions need to use pointer event suppression.
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	*
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	* If this class is used to suppress drag events during a possible
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	* tap, and this function does not suppress a drag event, the
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	* client can be sure that a drag action is happening.
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	*
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	* @param aPointerEvent the pointer event which may need to be suppressed.
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	* @return ETrue if the pointer event should be suppressed, or EFalse if it should be handled.
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	*/
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	IMPORT_C TBool SuppressPointerEvent(const TPointerEvent& aPointerEvent);
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	/**
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	* Set the maximum time period that drag events should be
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	* ignored during a pointer interaction.
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	*
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	* @param aDuration the maximum duration of a tap action.
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	*/
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	IMPORT_C void SetMaxTapDuration(TTimeIntervalMicroSeconds aDuration);
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	/**
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	* Set the maximum pointer movement for which drag events
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	* should be ignored during a pointer interaction.
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	*
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	* @param aMoveLimits the pixel movement limits within which a touch action is considered a tap
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	*/
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	IMPORT_C void SetMaxTapMove(TSize aMoveLimits);
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	/**
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	* Set the minimum time between drag events.
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	* This can be used to reduce the frequency of drag event reception when
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	* events are not desired at maximum speed.
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	*
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	* @param aInterval the minimum interval between which drag events are wanted
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	*/
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	IMPORT_C void SetMinInterDragInterval(TTimeIntervalMicroSeconds aInterval);
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private:
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	CAknPointerEventSuppressor();
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private:
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	TTimeIntervalMicroSeconds iMaxTapDuration;
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	TSize iMaxTapMove;
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	TTimeIntervalMicroSeconds iMinInterDragInterval;
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	TTime iDownTime;
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	TPoint iDownPos;
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	TBool iTap;
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	TTime iLastEventTime;
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	};
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#endif