// Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//

#ifndef __COEVIEW_H__
#define __COEVIEW_H__

#include <vwsdef.h>
#include <coemain.h> // for CCoeStatic

class CCoeAppUi;
class TVwsViewEvent;

/** Specifies an interface for views. 

This class should be implemented by all application views. 

@publishedAll
@released */
class MCoeView
	{
public:	
	/** Returns a TVwsViewId uniquely identifying the view.
	
	@return Represents a view in the server. */
	virtual TVwsViewId ViewId() const=0;
private:
	/** Takes any action required when a view is activated. Reimplemented versions 
	should read the contents of aCustomMessage for any message type identified 
	by aCustomMessageId that the view understands.
	
	The ID of the previously active view aPrevViewId is supplied so that the activated 
	view can subsequently switch back to the caller if required.
	
	@param aPrevViewId The UID of the previously active view.
	@param aCustomMessageId Message type.
	@param aCustomMessage Message contents. 

	@publishedAll
	@released */
	virtual void ViewActivatedL(const TVwsViewId& aPrevViewId,TUid aCustomMessageId,const TDesC8& aCustomMessage)=0;
	/** Takes any action that is required following deactivation of the view. 
	
	This reduces the work required of the window server.

	@publishedAll
	@released */
	virtual void ViewDeactivated()=0;

protected:
	IMPORT_C MCoeView();
	IMPORT_C virtual TVwsViewIdAndMessage ViewScreenDeviceChangedL();
private:
	IMPORT_C virtual void ViewConstructL();
protected:
	IMPORT_C virtual TBool ViewScreenModeCompatible(TInt aScreenMode); // was MCoeView_Reserved_1()
private:
	friend class CCoeViewManager;
	IMPORT_C virtual void PrepareForViewActivation();
	IMPORT_C virtual void MCoeView_Reserved_2();
	IMPORT_C virtual void MCoeView_Reserved_3();
private:
	TInt iMCoeView_Reserved1;
	};

/** An interface through which view events can be notified to an observer.

@publishedAll
@released */
class MCoeViewObserver
	{
public:
	virtual void HandleViewEventL(const TVwsViewEvent& aEvent)=0;
protected:
	IMPORT_C MCoeViewObserver();
private:
	IMPORT_C virtual void MCoeViewObserver_Reserved1();
	IMPORT_C virtual void MCoeViewObserver_Reserved2();
private:
	TInt iMCoeViewObserver_Reserved1;
	};

/** An interface through which view activations can be notified to an observer.

@publishedAll
@released
*/
class MCoeViewActivationObserver
	{
public:
	//
	// Handles the activation of the view aNewlyActivatedViewId before the old view aViewIdToBeDeactivated is
	// to be deactivated.
	//
	virtual void HandleViewActivation(const TVwsViewId& aNewlyActivatedViewId,const TVwsViewId& aViewIdToBeDeactivated)=0;
protected:
	IMPORT_C MCoeViewActivationObserver();
private:
	IMPORT_C virtual void MCoeViewActivationObserver_Reserved_1();
	IMPORT_C virtual void MCoeViewActivationObserver_Reserved_2();
private:
	TInt iMCoeViewActivationObserver_Reserved1;
	};

/** An interface through which view deactivations can be
notified to an observer.

Dialogs and other floating windows such as virtual keyboards which should be dismissed
when a view is deactivated can implement this interface and take any action required.

@publishedAll
@released */

class MCoeViewDeactivationObserver
	{
public:
	//
	// Handles the deactivation of the view identified by aViewIdToBeDeactivated before the newly activated
	// view with id aNewlyActivatedViewId is marked as current.
	//
	virtual void HandleViewDeactivation(const TVwsViewId& aViewIdToBeDeactivated,const TVwsViewId& aNewlyActivatedViewId)=0;
protected:
	IMPORT_C MCoeViewDeactivationObserver();
private:
	IMPORT_C virtual void MCoeViewDeactivationObserver_Reserved_1();
	IMPORT_C virtual void MCoeViewDeactivationObserver_Reserved_2();
private:
	TInt iMCoeViewDeactivationObserver_Reserved1;
	};

//
// Handles any screen device changes that occur while a view is active 
//
/** A default screen device change handler. 

This class is used to activate a default view when a screen "flip" occurs, 
if the currently active view does not implement MCoeView::ViewScreenDeviceChangedL().

@publishedAll 
@released
@see MCoeView::ViewScreenDeviceChangedL() */
class CCoeScreenDeviceChangeDefaultHandler : public CCoeStatic
	{
public:
	IMPORT_C ~CCoeScreenDeviceChangeDefaultHandler();
	IMPORT_C static CCoeScreenDeviceChangeDefaultHandler* Self();
protected:
	IMPORT_C CCoeScreenDeviceChangeDefaultHandler();
	IMPORT_C CCoeScreenDeviceChangeDefaultHandler(TInt aDestructionPriority);
private:
	IMPORT_C virtual void CCoeStatic_Reserved1();
	IMPORT_C virtual void CCoeStatic_Reserved2();
	IMPORT_C virtual void CCoeScreenDeviceChangeDefaultHandler_Reserved1();
	IMPORT_C virtual void CCoeScreenDeviceChangeDefaultHandler_Reserved2();
public:
	virtual void HandleScreenDeviceChangedL()=0;
	virtual TVwsViewIdAndMessage DefaultViewOnScreenDeviceChanged()=0;
private:
	TInt iCCoeScreenDeviceChangeDefaultHandler;
	};


#endif	// __COEVIEW_H__