/*

* Copyright (c) 2006 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:  Unit multi-field numeric editor

*

*/

#ifndef CAKNUNITEDITOR_H

#define CAKNUNITEDITOR_H

#include <eikmfne.h>

class CAknMfneFloat;

class CAknMfneSeparator;

/**

 * A multi-field numeric editor for displaying and editing a floating value

 * and an associated label.

 *

 * CAknUnitEditor is a multi-field numeric editor (MFNE), which is used for

 * displaying and editing floating point numeric data with a textual

 * label. Unit in the class name refers to a unit of measurement, for

 * example distance or speed, hence a typical use case might be an editor

 * which is used to edit an altitude value for a position in a GPS

 * application.

 *

 * Creating the editor is carried out by using either NewL() or

 * NewLC() function followed by a call to either ConstructL()

 * or ConstructFromResourceL() function. Note that if the editor is

 * not constructed fully, most functions will panic with KERN-EXEC 3.

 *

 * The value to be shown by the editor must be set at construction, and

 * can be later set using SetValue(). The current value of the editor

 * can be retrieved using Value().

 *

 * Minimum and maximum limits can be set using the function

 * SetMinimumAndMaximum(). NaN values for this function are

 * not supported, and will cause undefined behaviour.

 *

 * The editor supports a label shown next to the value. This label can be

 * set to a custom value (referred to as custom unit), or a set of

 * predefined and localized units can be used. See TAknUnitEditorUnits in

 * eikon.hrh and the two overloads of SetUnitL(). Note that the editor

 * discards the custom unit when a localized unit is set, so setting

 * the localized unit back to EAknUnitEditorCustomUnit clears

 * the unit.

 *

 * The editor supports variable number of fractional digits. A value

 * with no fractional part at all can also be displayed and edited. This

 * feature can be used with the function SetMaxFractionalDigits(), and

 * the corresponding getter MaxFractionalDigits(). Values set using

 * construction functions or SetValue() are rounded to correspond

 * with the number of fractional digits, so data loss may occur in such

 * case.

 *

 * The editor also supports an uninitialized state, which in practice means

 * that it can have nothing to display and in such case contains a

 * 'not a number' (NaN) value. This state can be allowed by the using the flag

 * EAknUnitEditorAllowUninitialized, found in TAknUnitEditorFlags in

 * eikon.hrh. For more information about NaN, see Math::IsNaN() and

 * TRealX::SetNaN().

 *

 * @lib eikctl.lib

 * @since S60 v3.2

 */

NONSHARABLE_CLASS( CAknUnitEditor ) : public CEikMfne

    {

public:

    /**

     * Creates a new CAknUnitEditor object. The client must call ConstructL()

     * or ConstructFromResourceL() after calling this function.

     *

     * @return The created CAknUnitEditor.

     */

    IMPORT_C static CAknUnitEditor* NewL();

    /**

     * Creates a new CAknUnitEditor object, leaving it in the cleanup stack.

     * The client must call ConstructL() or ConstructFromResourceL()

     * after calling this function.

     *

     * @return The created CAknUnitEditor.

     */

    IMPORT_C static CAknUnitEditor* NewLC();

    /**

     * C++ destructor. Deletes all owned member data.

     */

    virtual ~CAknUnitEditor();

    /**

     * Second-phase constructor. This should be called after creating a

     * new editor object with NewL() or NewLC(), if the

     * editor is not constructed from a resource.

     *

     * @param aMinimumValue The minimum allowable value.

     * @param aMaximumValue The maximum allowable value.

     * @param aInitialValue The initial value, can be NaN if the editor

     *                      is set to support it by using the

     *                      EAknUnitEditorAllowedUninitialized flag.

     * @param aMaxFractionalDigits The maximum number of fractional digits.

     * @param aUnit The unit type, see TAknUnitEditorUnits

     *              in eikon.hrh. Can be set to EAknUnitEditorCustomUnit

     *              or zero if you plan on using a custom unit.

     * @param aFlags The editor flags, see TAknUnitEditorFlags

     *               in eikon.hrh. This can be set to zero if no flags

     *               are desired. This is also the default parameter.

     * @leave KErrNotSupported If the given predefined unit type, aUnit,

     *                         is not found.

     * @see TAknUnitEditorUnits

     * @see TAknUnitEditorFlags

     */

    IMPORT_C void ConstructL(

        TReal aMinimumValue, TReal aMaximumValue,

        TReal aInitialValue,

        TInt aMaxFractionalDigits, TInt aUnit, TUint aFlags = 0 );

    /**

     * Second-phase constructor. This should be called after creating a

     * new editor object with NewL() or NewLC(), if the

     * editor is constructed from a resource. The resource structure

     * used in creating the editor is AVKON_UNIT_EDITOR.

     *

     * @param aResourceReader A resource file reader.

     * @leave KErrNotSupported If the predefined unit type in the resource

     *                         is not found.

     * @see AVKON_UNIT_EDITOR

     */        

    IMPORT_C void ConstructFromResourceL( TResourceReader& aResourceReader );

    /**

     * Sets a value to the editor. If the value is too large or small it is

     * set to maximum or minimum value, respectively. In case of an 

     * unallowed NaN the value is set to be the maximum value.

     *

     * @param aValue The value to be set.

     * @return ETrue, if the value was valid and not changed. The value is

     *         also considered to be valid in case it is rounded to the

     *         limits of the editor's maximum fractional digits.

     */

    IMPORT_C TBool SetValue( TReal aValue );

    /**

     * Gets the value from the editor.

     *

     * @return The value from the editor.

     */

    IMPORT_C TReal Value() const;

    /**

     * Tests if particular predefined unit type is supported.

     *

     * @param aUnit The predefined unit type, from the enum

     *              TAknUnitEditorUnits.

     * @return ETrue, if the given predefined unit type is supported.

     * @see TAknUnitEditorUnits

     */

    IMPORT_C TBool SupportsUnit( TInt aUnit ) const;

    /**

     * Sets the custom unit type. There's no actual limit for the length of

     * the text, but if the unit text overflows, it will not be wrapped.

     *

     * @param aUnit The unit type to be set.

     */

    IMPORT_C void SetUnitL( const TDesC& aUnit );

    /**

     * Sets the predefined and localized unit type. If the given unit type

     * is EAknUnitEditorCustomUnit, the unit field is emptied and a

     * subsequent call to SetUnitL( const TDesC& aUnit ) is needed.

     *

     * @param aUnit The predefined unit type, from the enum

     *              TAknUnitEditorUnits.

     * @leave KErrNotSupported If the given predefined unit type is not found.

     * @see TAknUnitEditorUnits

     */

    IMPORT_C void SetUnitL( TInt aUnit );

    /**

     * Gets the current unit type as a descriptor. This returns the textual

     * representation of the unit field, regardless of the way it was set.

     *

     * @param aDes On return, contains the editor's unit type if it fits in

     *             the given descriptor.

     * @return Zero, if the function executed successfully. Otherwise the

     *         minimum length needed for the editor's content.

     */

    IMPORT_C TInt GetUnit( TDes& aDes ) const;

    /**

     * Gets the current unit type as an predefined unit type id,

     * from the enum TAknUnitEditorUnits. Returns EAknUnitEditorCustomUnit

     * if the last unit set was a custom unit.

     *

     * @return The current unit type identifier. EAknUnitEditorCustomUnit

     *         if custom unit was set.

     * @see TAknUnitEditorUnits  

     */

    IMPORT_C TInt Unit() const;

    /**

     * Sets the maximum number of digits to show in the fractional part of

     * the value. The maximum number of fractional digits is limited

     * to eight. Setting a value outside of valid range (0 to 8) has

     * no effect in release builds, and panics in debug builds.

     *

     * @param aFractionalDigits The maximum number of digits in the

     *                          fractional part. Can be zero to eight.

     * @panic 1 In debug builds only, if aMaxFractionalDigits is out of

     *          range.

     */

    IMPORT_C void SetMaxFractionalDigits( TInt aMaxFractionalDigits );

    /**

     * Gets the maximum number of digits in the fractional part of the

     * value.

     *

     * @return The maximum number of digits in the fractional part

     */

    IMPORT_C TInt MaxFractionalDigits() const;

    /**

     * Sets the minimum and maximum editor values. NaN values are not

     * supported, and will cause undefined behaviour.

     *

     * @param aMinimumValue The minimum allowable value

     * @param aMaximumValue The maximum allowable value

     */

    IMPORT_C void SetMinimumAndMaximum(

        TReal aMinimumValue, TReal aMaximumValue );

    /**

     * Gets the minimum and maximum editor values.

     *

     * @param aMinimumValue On return, contains the editor's minimum value

     * @param aMaximumValue On return, contains the editor's maximum value

     */

    IMPORT_C void GetMinimumAndMaximum(

        TReal& aMinimumValue, TReal& aMaximumValue ) const;

    /**

     * Sets the editor flags, see TAknUnitEditorFlags in eikon.hrh.

     *

     * @param aFlags The editor flags. Note that this overrides all

     *               the flags. Use zero if no flags are desired.

     * @see TAknUnitEditorFlags

     */

    IMPORT_C void SetFlags( TUint aFlags );

    /**

     * Gets the editor flags, see TAknUnitEditorFlags in eikon.hrh.

     *

     * @return The editor flags.

     * @see TAknUnitEditorFlags

     */

    IMPORT_C TUint Flags() const;

// from base class CEikMfne

    /**

     * From CEikMfne.

     * Validates the values in the editor. This function should be called

     * before removing focus from the editor.

     *

     * @leave KLeaveWithoutAlert If the value in the field had an error

     *                           in it.

     */

    IMPORT_C void PrepareForFocusLossL();

protected:

    /**

     * From CEikMfne.

     * Deals with focus changes.

     *

     * @param aDrawNow Whether to draw the control immediately.

     */

     void FocusChanged( TDrawNow aDrawNow );

private:

    /**

     * C++ constructor.

     */

    CAknUnitEditor();

    /**

     * Checks if the unit field label should be visible.

     *

     * @return ETrue, if the unit field should be visible.

     */

    TBool UnitFieldVisibility() const;

private: // data

    /**

     * Bit flags

     */

    TUint iFlags;

    /**

     * The limit for predefined unit indices

     */

    const TInt iUnitLimit;

    /**

     * Value of the current unit type, as in enum

     * TAknUnitEditorUnits.

     */

    TInt iUnitType;

    /**

     * Helper pointer to float value field

     * Not own.

     */

    CAknMfneFloat* iFloatField;

    /**

     * Helper pointer to separator field

     * Not own.

     */

    CAknMfneSeparator* iSeparatorField;

    /**

     * Helper pointer to unit field

     * Not own.

     */

    CAknMfneSeparator* iUnitField;

    };

#endif // CAKNUNITEDITOR_H