/*

* Copyright (c) 1997-1999 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* which accompanies this distribution, and is available

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

#if !defined(__EIKEDWOB_H__)

#define __EIKEDWOB_H__

class CEikEdwin;

/**

 * Interface class describing the functionality expected of an observer

 * for CEikEdwins.

 * 

 * Edwin observers are informed by the edwin whenever its content is

 * changed, or whenever the user changes the cursor position.

 * 

 * This class should be derived from by all observers of edwins.

 */

class MEikEdwinObserver

	{

public:

    /**

     * Events from a value editor.

     */

	enum TEdwinEvent

		{

		/** Sent whenever the content of the edwin changes. */

		EEventFormatChanged,

		/** Sent on receipt of a navigation command. */

		EEventNavigation,

		/**

		 * Sent whenever the text of the edwin changes. To observe

		 * actual changes in the contents of the editor this should

		 * be preferred to EEventFormatChanged.

		 */

		EEventTextUpdate,

		/** Sent on receipt of a scroll event. */

		EEventScroll,

		/** Sent if you explicitly call edwin's SetTextL() */

		};

public:

    /**

     * This pure virtual function is invoked by CEikEdwin to report an event

     * to its observer. The observer may respond appropriately.

     * 

     * @param aEdwin  The originating edwin. 

     * @param aEventType  The event being reported. 

     */

	virtual void HandleEdwinEventL(CEikEdwin* aEdwin,TEdwinEvent aEventType)=0;

	};

/**

 * Interface to handle changes to an edwin's size.

 */

class MEikEdwinSizeObserver

	{

public:

    /**

     * Specifies the type of event reported to the edwin observer.

     */

	enum TEdwinSizeEvent

		{

		/**

		 * Specifies a change in edwin size. When the edwin observer

		 * receives an event of this type, it handles it by making

		 * its view bigger or smaller according to the new edwin size.

		 */

		EEventSizeChanging

		};

public:

    /**

     * Handles a change in the edwin's size. If you implement this function,

     * ensure it returns ETrue if you wish to redraw the edwin.

     * 

     * @param aEdwin The edwin for which the size event is being handled.

     * @param aEventType The event type.

     * @param aDesirableEdwinSize The desired size for the edwin identified

     * by aEdwin.

     * @return The return value depends on your implementation. Return

     * ETrue if you wish to redraw the edwin. EFalse otherwise.

     */

	virtual TBool HandleEdwinSizeEventL(CEikEdwin* aEdwin, TEdwinSizeEvent aEventType, TSize aDesirableEdwinSize)=0;

	};

#endif