QdbtBaseCell class Reference

When interacting with a cell (e.g. modifying its properties), the clone()-method may be used. You might use code like to following to retreive a cell from a QdbtBaseTabular widget called tabular:

  // create a local copy of the cell
  QdbtBaseCell *cell = tabular->cell( row, col )->clone();

  // change some properties of the cell
  .
  .
  .

  QdbtIntCell *intCell = dynamic_cast<QdbtIntCell*>(cell);
  if ( intCell ) {
    intCell->setValue( intCell->value()+1 );
  }

  .
  .
  .

  // update the cell at (row,col) in the table
  tabular->changeCell( cell, row, col );
  delete cell;

For backward compatibility, the API of QdbtTabular/QdbtTableCell provide a different way to interact with cell. Please not, that due to subclassing no plain copy-contructor may be used to reproduce an object. This the clone()-method is used to leave reproduction of cells to the cells itself.

Since cloning resolves in allocating a new object of the cell's type, this object has to be deleted if it is not used any more.

Constructor & Destructor Documentation

QdbtBaseCell::~QdbtBaseCell ( ) [virtual]

The virtual destructur frees all data, the cell allocated.

QdbtBaseCell::QdbtBaseCell ( ) [protected]

The constructor creates an empty cell.

For handling the context (might be necessary for interacting with the singleton class that can store editor widget instances), the pointer of the tabualr widget is being passed.

Member Function Documentation

bool QdbtBaseCell::aboutToBeEdited ( QdbtBaseTabular * tab ) const [protected]

This function interacts with the table and clarifies, if a new editing session may be started. If this function returns FALSE, no edit session may be started currently.

See also:: beginEdit()

bool QdbtBaseCell::acceptEdit	(	QdbtBaseTabular *	,
		int	row,
		int	col
	)	`[protected, virtual]`

If a cell is currently being edited and for any reason, another cells is supposed to be transfered into editing mode, the table triggers this function to make a cell accept its changes. If, for any reason, the content of the cell is not acceptable and the cell returns FALSE, the table will not start an editing session for the new cell.

When acceptEdit() returns TRUE, the tabular expects that the cell editor has been reset and made invisible again before this function returns.

See also:: cancelEdit()

Reimplemented in QdbtComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

const QColor & QdbtBaseCell::background ( QdbtBaseTabular * tab ) const [virtual]

This function computes the background color for a table's cell. This color is generated from the table-component's forground color, if it is existing. If not (e.g. if the pointer to the tabular tab is not supplied correctly), a default color or white is supplied.

Reimplemented in QdbtTableCell.

bool QdbtBaseCell::beginEdit	(	QdbtBaseTabular *	,
		int	row,
		int	col,
		const QRect	cellGeometry
	)	const `[protected, virtual]`

This function is called by the table to put a single cell into editing mode. The cells is expected to return TRUE if it transfered itself into editing mode and FALSE of for any reason this task could not be performed.

When beginEdit() returns TRUE, the tabular expects that the cell editor has been initialized and made visible within the rectangle that is transfered as cellGeometry .

See also:: aboutToBeEdited()

Reimplemented in QdbtComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

bool QdbtBaseCell::cancelEdit	(	QdbtBaseTabular *	,
		int	row,
		int	col
	)	`[protected, virtual]`

If an edit-session has to be canceled for any reason, the table will use this function to ask for cancellation of an edit-session. The edit-session should then be canceled if possible.

When cancelEdit() returns TRUE, the tabular expects that the cell editor has been reset and made invisible again before this function returns.

See also:: acceptEdit()

Reimplemented in QdbtComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

bool QdbtBaseCell::cleanupEditor ( QdbtBaseTabular * tab ) const [protected]

This member cleans up a cell's editor and ensures that the editor is not visible any longer.

Parameters:

tab

The tabular, to which the cell belongs

Returns:: TRUE if the editor has been cleaned up correctly, FALSE otherwise. If this function returns FALSE, it has not take any actions.

Attention:: This function relies on the editor()-function to answer the correct cell editor widget.

See also:: prepareEditor()

QdbtBaseCell * QdbtBaseCell::clone ( QdbtBaseTabular * tabular ) const [pure virtual]

This abstract method is being used to produce a new instance with exactly the same internal state as the original object was. If is being used whenever a copy of a cell has to be produced, e.g. when changing cells within the tabular widget's table matrix.

For initializing the new cell properly, the context of the cell (the tabular widget, that it is located in) is being transfered to the clone() function.

Warning:: This function is virtually used as a virtual constructor. Please refer to the Prototype paragraph from Erich Gamma et. al, 'Design Patterns, Elements of Reusable Object-Oriented Software', Addison-Wesley, 1995 (a book definitely worth its price)

Implemented in QdbtNoCell, QdbtComboCell, QdbtBorderlessComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

const QColor & QdbtBaseCell::color ( QdbtBaseTabular * tab ) const [virtual]

This function computes the forground color for a table's cell. This color is generated from the table-component's forground color, if it is existing. If not (e.g. if the pointer to the tabular tab is not supplied correctly), a default color or black is supplied.

Reimplemented in QdbtTableCell.

QWidget * QdbtBaseCell::editor ( QdbtBaseTabular * ) const [protected, virtual]

This functions serves to determine the editor widget associated to a table cell. This function should be provided within a derived class, since the function determining if a tabular contains the keyboard focus relies on it. However it is safe to return 0, if no editor may be returned or even is only produced on demand.

Reimplemented in QdbtComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

QFont QdbtBaseCell::font ( QdbtBaseTabular * tab ) const [protected]

Read the font, that has been set for the QdbtTabular Widget. This font should be used for all text-editor facilities.

Parameters:

tab

The context (tabular), with which the cell is used

QRect QdbtBaseCell::getEditArea ( int width ) const [virtual]

Returns the area inside the cell, where the edit focus may be placed. The coordinates of the rectangle are in pixels and relative to the cell. The top left of the cell has coordinates (0,0).

Reimplemented in QdbtComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

QRect QdbtBaseCell::getTextArea ( ) const [virtual]

Returns the area inside the cell, where the text is being drawn. The coordinates of the rectangle are in pixels and relative to the cell. The top left of the cell has coordinates (0,0).

Reimplemented in QdbtComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

bool QdbtBaseCell::isEditable

(

)

const

Returns TRUE if the cell may be edited by the user.

See also:: setEditable().

bool QdbtBaseCell::keyEvent	(	QdbtBaseTabular *	,
		int	row,
		int	col,
		QKeyEvent *	e,
		const QRect	cellGeometry
	)	`[protected, virtual]`

This method is used to inform a table cell about a key press event. The cell receives its coordinates with the table's matrix as row, col, all information on the key pressed e as well as its current geometry cellGeometry in the coordinate system of the table's cell matrix.

If this method returns FALSE, the table will apply the normal 'keyboard' rules (cursor keys traverse the focus, etc). If the method returns TRUE, the table components assume, that anything necessary has already been taken care of.

Reimplemented in QdbtComboCell.

bool QdbtBaseCell::mouseEvent	(	QdbtBaseTabular *	,
		int	row,
		int	col,
		QMouseEvent *	e,
		const QRect	cellGeometry
	)	`[protected, virtual]`

This method is used to inform a table cell about a mouse press event. The cell receives its coordinates with the table's matrix as row, col, the coordinates of the mouse click relative to the table's cell matrix as e as well as its current geometry cellGeometry in the coordinate system of the table's cell matrix.

If this method returns FALSE, the table will apply the normal 'editing' rules (center mousebutton will edit the cell). If the method returns TRUE, the table components assume, that anything necessary has already been taken care of.

Reimplemented in QdbtComboCell.

void QdbtBaseCell::moveEditor	(	QdbtBaseTabular *	tab,
		const QRect	geom
	)	const `[protected, virtual]`

This method is called whenever a table cell is being edited and the table is repainted. The method should check if the geometry of handed over is the same as the geometry applied to the editor widget and - if not - should resize or move the editor widget to the correct position.

The default implementation determines the editor widget by calling editor() and moves it to the correct location.

void QdbtBaseCell::notifyOnEditResult	(	QdbtBaseTabular *	tab,
		int	row,
		int	col,
		int	result,
		QString	oldText
	)	`[protected]`

This function interacts with the tabular components and may be used to communicate the result of an edit session to the remaining programm parts.

void QdbtBaseCell::paint	(	QPainter *	p,
		QdbtBaseTabular *	t,
		const QRect &	r,
		bool	selected,
		bool	editing = FALSE
	)	`[virtual]`

This function is called whenever the cell needs to be repainted. The width of the cell is w and the height is h is passed. To be able to interact with the tabular widget (e.g. for style support) that paints this cell, a pointer to it is passed to this function. The painter p automatically clips against the area of the cell. The boolean selected indicates if the cell is selected. The boolean editing indicates if the cell is currently being edited.

Reimplemented in QdbtNoCell, QdbtComboCell, QdbtBorderlessComboCell, QdbtIntCell, QdbtTableCell, QdbtTextCell, and QdbtValidatingCell.

void QdbtBaseCell::paintFocus	(	QPainter *	p,
		QdbtBaseTabular *	t,
		const QRect &	r,
		bool	selected,
		bool	editing = FALSE
	)	`[virtual]`

This function is called whenever the cell's focus needs to be repainted. The width of the cell is w and the height is h is passed. To be able to interact with the tabular widget (e.g. for style support) that paints this cell, a pointer to it is passed to this function. The painter p automatically clips against the area of the cell.

Reimplemented in QdbtComboCell, and QdbtBorderlessComboCell.

bool QdbtBaseCell::prepareEditor	(	QdbtBaseTabular *	tab,
		const QRect &	geom
	)	const `[protected]`

Prepare the cell's editor for the about-to-be-started edit session.

Parameters:

tab	The tabular, to which this cell belongs
geom	The cell (and thus the editor's) geometry

Returns:: TRUE, if the editor has been configured appropriately, FALSE otherwise. If this function returns FALSE, it has not take any actions.

Attention:: This function relies on the editor()-function to anser the correct cell editor widget.

See also:: cleanupEditor()

void QdbtBaseCell::rightButtonClicked	(	QdbtBaseTabular *	tab,
		int	row,
		int	col
	)	const

This functions informs the user, that the right mouse buttons has been pressed on top of the cell in row row and col col. This method should be used within each of the editor widgets mapped on top of the table components, for the 'normal' cells this signal is begin generated automatically.

void QdbtBaseCell::setEditable ( bool state ) [virtual]

Sets whether or not the cell may be edited by the application user.

If state is TRUE the cell may be edited.

If state is FALSE the cell may not be edited.

See also:: isEditable().

Examples:: example1.cpp, example3.cpp, example4.cpp, and example5.cpp.

void QdbtBaseCell::setEditorEnabled	(	QdbtBaseTabular *	tab,
		bool	enable
	)	const `[protected, virtual]`

This function serves to temporaryly disable/enable the editor widget, if there is any.

The default implementation determines the editor widget by calling editor() and disables or enables it according to enable.

Friends And Related Function Documentation

friend class QdbtTable [friend]

This friend declaration allows the table widget instance to interact with the cells through the protected API components.

Member Data Documentation

QdbtBaseCell::bw = 4 [static, protected]

Default spacing value for tabular cells.

Public Methods
virtual	~QdbtBaseCell ()
virtual QdbtBaseCell *	clone (QdbtBaseTabular *) const=0
virtual int	widthHint (const QFontMetrics &fm) const
virtual int	heightHint (const QFontMetrics &fm) const
virtual const QColor &	color (QdbtBaseTabular *) const
virtual const QColor &	background (QdbtBaseTabular *) const
virtual QString	text () const
virtual void	setEditable (bool state)
bool	isEditable () const
virtual void	paint (QPainter p, QdbtBaseTabular t, const QRect &r, bool selected, bool editing=FALSE)
virtual void	paintFocus (QPainter p, QdbtBaseTabular t, const QRect &r, bool selected, bool editing=FALSE)
virtual QRect	getTextArea () const
virtual QRect	getEditArea (int width) const
void	rightButtonClicked (QdbtBaseTabular *tab, int row, int col) const
Protected Methods
	QdbtBaseCell ()
virtual QWidget *	editor (QdbtBaseTabular *) const
virtual bool	beginEdit (QdbtBaseTabular *, int row, int col, const QRect cellGeometry) const
virtual bool	acceptEdit (QdbtBaseTabular *, int row, int col)
virtual bool	cancelEdit (QdbtBaseTabular *, int row, int col)
virtual bool	mouseEvent (QdbtBaseTabular , int row, int col, QMouseEvent e, const QRect cellGeometry)
virtual bool	keyEvent (QdbtBaseTabular , int row, int col, QKeyEvent e, const QRect cellGeometry)
virtual void	setEditorEnabled (QdbtBaseTabular *, bool) const
virtual void	moveEditor (QdbtBaseTabular *, const QRect cellGeometry) const
bool	aboutToBeEdited (QdbtBaseTabular *) const
void	notifyOnEditResult (QdbtBaseTabular *tab, int row, int col, int result, QString oldText)
QFont	font (QdbtBaseTabular *) const
bool	prepareEditor (QdbtBaseTabular *tab, const QRect &geom) const
bool	cleanupEditor (QdbtBaseTabular *tab) const
Static Protected Attributes
int	MASK_EDITABLE = 0x0001
int	MASK_SELECTABLE = 0x0002
int	MASK_SELECTED = 0x0004
int	bw = 4
Friends
class	QdbtTable
class	QdbtEditorBase

QdbtBaseCell Class Reference
[Cell implementations]

Public Methods

Protected Methods

Static Protected Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation

QdbtBaseCell Class Reference [Cell implementations]

Public Methods

Protected Methods

Static Protected Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation

QdbtBaseCell Class Reference
[Cell implementations]