The LayoutManager class is the base class of the layout managers. More...

#include <LayoutManager.h>

Inheritance diagram for LayoutManager:

Public Member Functions
virtual void	AddItem (LayoutItem *item)=0
	Adds a LayoutItem to this Layout Manager. More...

virtual LayoutItem *	ItemAt (int index) const =0
	Retrieves the item at index in the layout and returns the item. More...

virtual LayoutItem *	TakeAt (int index)=0
	Removes the item at index from the layout, and returns the item. More...

virtual size_t	Count () const =0
	Returns the number of items in this layout. More...

virtual void	Invalidate ()
	Resets the layout's rectangle then calls Update() More...

virtual void	SetDirty ()
	Resets the layout's rectangle. More...

virtual int	GetSpacing () const
	Gets the spacing between items in the layout. More...

virtual void	SetSpacing (int spacing)
	Sets the spacing between items in the layout. More...

virtual int	IndexOf (LayoutControl *ctl) const
	Searches for the control in this layout (not including child layouts). More...

virtual int	IndexOf (LayoutItem *item) const
	Searches for the LayoutItem in this layout (not including child layouts). More...

void	WindowSizeDoLayout (const BSize &size)
	Notifies this LayoutManager that the Window size has changed and all child items should be laid out accordingly. More...

void	VisibleDoLayout ()
	Notifies this LayoutManager that the layout has changed visibility and all child items should be laid out accordingly. More...

void	ItemSizeDoLayout ()
	Notifies this LayoutManager that a child has changed size and all child items should be laid out accordingly. More...

LayoutManager *	GetMainLayout ()
	Retrieves the main LayoutManager associated with this Layout Manager. More...

LayoutManager *	GetSharedSizeGroupBoundary ()
	Retrieves the next Shared Size Group Boundary associated with this Layout Manager. More...

LayoutManager *	GetParentLayout () const
	Retrieves the parent LayoutManager associated with this Layout Manager. More...

void	SetParentLayout (LayoutManager *)
	Sets the parent LayoutManager for this Layout Manager. More...

LayoutControl *	GetParentControl () const
	Retrieves the parent LayoutControl associated with this Layout Manager. More...

void	SetParentControl (LayoutControl *)
	Sets the parent LayoutControl for this Layout Manager. More...

int	GetMargin () const
	Retrieves the margin for the LayoutManager, but only if all 4 margins are the same. Otherwise, -1 is returned. More...

void	SetMargin (int margin)
	Sets the 4 margins for the LayoutManager to the same value. More...

void	SetLayoutMargins (int left, int top, int right, int bottom)
	Sets the 4 margins for the LayoutManager. More...

void	SetLayoutMargins (const Margins &margins)
	Sets the margins for the LayoutManager. More...

void	GetLayoutMargins (int left, int top, int right, int bottom) const
	Gets the 4 margins for the LayoutManager. More...

Margins	GetLayoutMargins () const
	Gets the 4 margins for the LayoutManager. More...

BRect	GetContentsRect () const
	Gets the bounding rectangle for the contents in the LayoutManager. More...

bool	SetAlignment (LayoutControl *ctl, LayoutAlignment alignment)
	Sets the alignment for a child control. More...

bool	SetAlignment (LayoutManager *layout, LayoutAlignment alignment)
	Sets the alignment for a child layout. More...

bool	Activate ()
	Invalidates the layout item then updates it. More...

void	Update ()
	Invalidates the layout item without updating it. More...

void	RemoveControl (LayoutControl *ctl)
	Removes a child control. More...

void	RemoveItem (LayoutItem *item)
	Removes a child item. More...

int	GetTotalHeightForWidth (int width) const
	Retrieves the required height for a given width. More...

BSize	GetTotalMinimumSize () const
	Retrieves the total minimum size for the layout. More...

BSize	GetTotalMaximumSize () const
	Retrieves the total maximum size for the layout. More...

BSize	GetTotalDesiredSize () const
	Retrieves the total desired size for the layout. More...

void	SetEnabled (bool)
	Sets whether the layout is enabled. More...

bool	IsEnabled () const
	Determines whether the layout is enabled. More...

void	SetTopLevel (bool)
	Sets whether the layout is top-level. More...

bool	IsTopLevel () const
	Determines whether the layout is top-level. More...

void	SetSharedSizeGroupBoundary (bool)
	Sets whether the layout is a Shared Group Boundary. More...

bool	IsSharedSizeGroupBoundary () const
	Determines whether the layout is a Shared Group Boundary. More...

virtual bool	IsEmpty () const override
	Returns whether the layout item is empty. More...

virtual bool	IsVisible () const override
	Returns whether the layout item is visible. More...

virtual BSize	GetMinimumSize () const override
	Returns the minimum size for this layout item. More...

virtual BSize	GetMaximumSize () const override
	Retrieves the maximum size for this layout item. More...

virtual void	SetGeometry (const BRect &rect) override
	Sets the geometry for this layout item to the given rectangle. More...

virtual BRect	GetGeometry () const override
	Retrieves the geometry for this layout item. More...

virtual LayoutManager *	GetLayout () override
	If the concrete item is a LayoutManager, it can be retrieved using GetLayout(). More...

virtual LayoutOrientations	GetExpandingOrientations () const override
	Returns whether this layout item can make use of more space than GetDesiredSize(). More...

Public Member Functions inherited from LayoutItem
virtual BSize	GetDesiredSize () const =0
	Returns the desired size for this layout item. More...

virtual BSize	GetSize () const
	Returns the geometry's size for this layout item. More...

virtual bool	HasHeightForWidth () const
	Returns whether this layout's preferred height depends on its width. More...

virtual int	GetHeightForWidth (int width) const
	Returns the preferred height for this layout item, given the width. More...

virtual int	GetMinimumHeightForWidth (int width) const
	Returns the minimum height for this layout item, given the width. More...

virtual LayoutControl *	GetControl ()
	If the concrete item is a LayoutControl, it can be retrieved using GetControl(). More...

LayoutAlignment	GetAlignment () const
	Returns the alignment within the layout for this layout item. More...

void	SetAlignment (LayoutAlignment alignment)
	Sets the alignment within the layout for this layout item. More...

Public Member Functions inherited from RefCounted< IRefCounted >
void *	operator new (size_t size)

void	operator delete (void *rawMemory, size_t size)

UInt32	AddRef () const

UInt32	Release () const

	RefCounted ()

	RefCounted (RefCounted const &rhs)

RefCounted &	operator= (RefCounted const &rhs)

UInt32	GetRefCount () const

Additional Inherited Members
Protected Member Functions inherited from RefCounted< IRefCounted >
virtual	~RefCounted ()

Protected Member Functions inherited from IRefCounted
virtual	~IRefCounted ()

void *	operator new (size_t size)

void	operator delete (void *rawMemory, size_t size)

Detailed Description

The LayoutManager class is the base class of the layout managers.

This is an abstract base class inherited by the concrete classes DockLayout, FlowLayout, GridLayout, SplitterLayout and StackLayout.

For users of LayoutManager subclasses there is seldom any need to use the basic functions provided by LayoutManager, such as SetSizeConstraint().

To make your own layout manager, implement the functions AddItem(), GetDesiredSize(), SetGeometry(), ItemAt() and TakeAt(). You should also implement GetMinimumSize() to ensure your layout isn't resized to zero size if there is too little space. To support children whose heights depend on their widths, implement HasHeightForWidth() and GetHeightForWidth().

Geometry management stops when the layout manager is deleted.

Member Function Documentation

bool Activate ( )

Invalidates the layout item then updates it.

virtual void AddItem ( LayoutItem * item )

pure virtual

Adds a LayoutItem to this Layout Manager.

Parameters

[in] item The layout item to add to the layout.

Remarks: Must be implemented in subclasses to add an item. How it is added is specific to each subclass.

This function is not usually called in application code. To add a control to a layout, use the AddControl() function; to add a child layout, use the AddLayout() function provided by the relevant LayoutManager subclass.

Note: The ownership of the item is transferred to the layout, and it's the layout's responsibility to delete it.

virtual size_t Count ( ) const

pure virtual

Returns the number of items in this layout.

Remarks: Must be implemented in subclasses to return the number of items in the layout.

Implemented in GridLayout, StackLayout, SplitterLayout, FlowLayout, and DockLayout.

BRect GetContentsRect ( ) const

Gets the bounding rectangle for the contents in the LayoutManager.

virtual LayoutOrientations GetExpandingOrientations ( ) const

overridevirtual

Returns whether this layout item can make use of more space than GetDesiredSize().

A value of LO_Vertical or LO_Horizontal means that it wants to grow in only one dimension, whereas LO_Vertical | LO_Horizontal means that it wants to grow in both dimensions.

Implements LayoutItem.

Reimplemented in GridLayout, StackLayout, FlowLayout, and DockLayout.

virtual BRect GetGeometry ( ) const

overridevirtual

Retrieves the geometry for this layout item.

Implements LayoutItem.

virtual LayoutManager* GetLayout ( )

overridevirtual

If the concrete item is a LayoutManager, it can be retrieved using GetLayout().

Reimplemented from LayoutItem.

void GetLayoutMargins	(	int *	left,
		int *	top,
		int *	right,
		int *	bottom
	)		const

Gets the 4 margins for the LayoutManager.

Each of the arguments may be NULL.

Parameters

[in]	left	Receives the left margin if not NULL
[in]	top	Receives the top margin if not NULL
[in]	right	Receives the right margin if not NULL
[in]	bottom	Receives the bottom margin if not NULL

Margins GetLayoutMargins ( ) const

Gets the 4 margins for the LayoutManager.

Returns: The margins for the LayoutManager

LayoutManager* GetMainLayout ( )

Retrieves the main LayoutManager associated with this Layout Manager.

This searches backwards recursively searching for the main layout.

int GetMargin ( ) const

Retrieves the margin for the LayoutManager, but only if all 4 margins are the same. Otherwise, -1 is returned.

virtual BSize GetMaximumSize ( ) const

overridevirtual

Retrieves the maximum size for this layout item.

Implements LayoutItem.

Reimplemented in GridLayout, StackLayout, and SplitterLayout.

virtual BSize GetMinimumSize ( ) const

overridevirtual

Returns the minimum size for this layout item.

Implements LayoutItem.

Reimplemented in GridLayout, StackLayout, SplitterLayout, FlowLayout, and DockLayout.

LayoutControl* GetParentControl ( ) const

Retrieves the parent LayoutControl associated with this Layout Manager.

LayoutManager* GetParentLayout ( ) const

Retrieves the parent LayoutManager associated with this Layout Manager.

LayoutManager* GetSharedSizeGroupBoundary ( )

Retrieves the next Shared Size Group Boundary associated with this Layout Manager.

This searches backwards recursively searching for the next Shared Size Group Boundary.

virtual int GetSpacing ( ) const

virtual

Gets the spacing between items in the layout.

Reimplemented in StackLayout, and GridLayout.

BSize GetTotalDesiredSize ( ) const

Retrieves the total desired size for the layout.

int GetTotalHeightForWidth ( int width ) const

Retrieves the required height for a given width.

Parameters

[in] width The width for which to determine the required height

BSize GetTotalMaximumSize ( ) const

Retrieves the total maximum size for the layout.

BSize GetTotalMinimumSize ( ) const

Retrieves the total minimum size for the layout.

virtual int IndexOf ( LayoutControl * ctl ) const

virtual

Searches for the control in this layout (not including child layouts).

Parameters

[in] ctl The control in the layout.

Returns: The index of the control, or - 1 if it is not found.

Remarks: The default implementation iterates over all items using ItemAt ().

Reimplemented in SplitterLayout.

virtual int IndexOf ( LayoutItem * item ) const

virtual

Searches for the LayoutItem in this layout (not including child layouts).

Parameters

[in] item The item in the layout.

Returns: The index of the LayoutItem, or - 1 if it is not found.

Remarks: The default implementation iterates over all items using ItemAt ().

Reimplemented in SplitterLayout.

virtual void Invalidate ( )

virtual

Resets the layout's rectangle then calls Update()

Reimplemented from LayoutItem.

Reimplemented in GridLayout, StackLayout, and SplitterLayout.

virtual bool IsEmpty ( ) const

overridevirtual

Returns whether the layout item is empty.

Implements LayoutItem.

bool IsEnabled ( ) const

Determines whether the layout is enabled.

bool IsSharedSizeGroupBoundary ( ) const

Determines whether the layout is a Shared Group Boundary.

bool IsTopLevel ( ) const

Determines whether the layout is top-level.

virtual bool IsVisible ( ) const

overridevirtual

Returns whether the layout item is visible.

Implements LayoutItem.

virtual LayoutItem* ItemAt ( int index ) const

pure virtual

Retrieves the item at index in the layout and returns the item.

If there is no such item, the function returns NULL.

Parameters

[in] index The index of the item to retrieve. Items are numbered consecutively from 0.

Remarks: ItemAt must be implemented in subclasses to return the layout item at index. If there is no such item, the function must return 0. Items are numbered consecutively from 0. If an item is deleted, other items will be renumbered. This function can be used to iterate over a layout.

Implemented in GridLayout, StackLayout, SplitterLayout, FlowLayout, and DockLayout.

void ItemSizeDoLayout ( )

Notifies this LayoutManager that a child has changed size and all child items should be laid out accordingly.

void RemoveControl ( LayoutControl * ctl )

Removes a child control.

Parameters

[in] ctl The child control

void RemoveItem ( LayoutItem * item )

Removes a child item.

Parameters

[in] item The child item

bool SetAlignment	(	LayoutControl *	ctl,
		LayoutAlignment	alignment
	)

Sets the alignment for a child control.

Parameters

[in]	ctl	The child control
[in]	alignment	The new LayoutAlignment value

bool SetAlignment	(	LayoutManager *	layout,
		LayoutAlignment	alignment
	)

Sets the alignment for a child layout.

Parameters

[in]	layout	The child layout
[in]	alignment	The new LayoutAlignment value

virtual void SetDirty ( )

virtual

Resets the layout's rectangle.

Reimplemented from LayoutItem.

Reimplemented in GridLayout, StackLayout, and SplitterLayout.

void SetEnabled ( bool )

Sets whether the layout is enabled.

virtual void SetGeometry ( const BRect & rect )

overridevirtual

Sets the geometry for this layout item to the given rectangle.

Parameters

[in] rect The rectangle of the new geometry for the layout item.

Implements LayoutItem.

Reimplemented in GridLayout, StackLayout, SplitterLayout, FlowLayout, and DockLayout.

void SetLayoutMargins	(	int	left,
		int	top,
		int	right,
		int	bottom
	)

Sets the 4 margins for the LayoutManager.

Parameters

[in]	left	The left margin
[in]	top	The top margin
[in]	right	The right margin
[in]	bottom	The bottom margin

void SetLayoutMargins ( const Margins & margins )

Sets the margins for the LayoutManager.

Parameters

[in] margins The new margins

void SetMargin ( int margin )

Sets the 4 margins for the LayoutManager to the same value.

Parameters

[in] margin The value used for the 4 margins.

void SetParentControl ( LayoutControl * )

Sets the parent LayoutControl for this Layout Manager.

void SetParentLayout ( LayoutManager * )

Sets the parent LayoutManager for this Layout Manager.

void SetSharedSizeGroupBoundary ( bool )

Sets whether the layout is a Shared Group Boundary.

virtual void SetSpacing ( int spacing )

virtual

Sets the spacing between items in the layout.

Parameters

[in] spacing The amount of space between items in the layout.

Reimplemented in StackLayout, and GridLayout.

void SetTopLevel ( bool )

Sets whether the layout is top-level.

virtual LayoutItem* TakeAt ( int index )

pure virtual

Removes the item at index from the layout, and returns the item.

If there is no such item, the function does nothing and returns NULL.

Parameters

[in] index The index of the item to remove. Items are numbered consecutively from 0.

Remarks: Must be implemented in subclasses to remove the layout item at index from the layout, and return the item. If there is no such item, the function must do nothing and return 0. Items are numbered consecutively from 0. If an item is removed, other items will be renumbered.

Implemented in GridLayout, StackLayout, SplitterLayout, FlowLayout, and DockLayout.

void Update ( )

Invalidates the layout item without updating it.

void VisibleDoLayout ( )

Notifies this LayoutManager that the layout has changed visibility and all child items should be laid out accordingly.

void WindowSizeDoLayout ( const BSize & size )

Notifies this LayoutManager that the Window size has changed and all child items should be laid out accordingly.

Parameters

[in] size The new size of the window.

The documentation for this class was generated from the following file:

LayoutManager.h

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation