BScrollView

Derived from: public BView

Declared in: be/interface/ScrollView.h

Library: libbe.so

Summary

A BScrollView object is a container for some other view (the target view). The BScrollView creates and positions scroll bars around the target view, and makes itself the parent of the scroll bars and the target view. When the user moves the scroll bars, the target view scrolls.

Constructor and Destructor

BScrollView()

	BScrollView(const char *name, BView *target,       uint32 resizingMode = B_FOLLOW_LEFT | B_FOLLOW_TOP,       uint32 flags = 0,       bool horizontal = false,       bool vertical = false,       border_style border = B_FANCY_BORDER) BScrollView(BMessage *archive)

Creates a BScrollView that has target as its target view. If horizontal is true, a horizontal scroll bar is added to the bottom of the target view. If vertical is true, a vertical scroll bar is added to the target's right side. The BScrollView's frame is manufactured for you to contain the target view, the scroll bars, and the optional border; the location of the target view doesn't change. The scroll bar "thickness" constants, defined in ScrollBar.h, will help you compute the size of the frame:

B_V_SCROLL_BAR_WIDTH	The width of a vertical scroll bar.
B_H_SCROLL_BAR_HEIGHT	The height of a horizontal scroll bar.

The target and the scroll bars are added as (sibling) children of the scroll view, and the target's TargetedByScrollView() function is called. The target must not already be the child of some other view.

The border argument can be one of three values:

B_PLAIN_BORDER	Draw a border consisting of just a simple line around the target view and scroll bars.
B_FANCY_BORDER	Draw a fancier border that looks like a 3D groove inset into the surface of the view.
B_NO_BORDER	Don't draw a border.

If the resize mode of the target view is B_FOLLOW_ALL_SIDES, it and the scroll bars will be automatically resized to fill the scroll view whenever the scroll view is resized.

The scroll bars created by the BScrollView have an initial range of 0 to 1000. Use the ScrollBar() function to retrieve the scroll bars and reset their ranges.

The name, resizingMode, and flags arguments are identical to those declared in the BView class and are passed to the BView constructor. If a border is requested, B_WILL_DRAW is automatically added to the flags mask. The other two arguments are passed to the BView class unchanged.

See also: the BView constructor, BView::TargetedByScrollView()

~BScrollView()

	virtual ~BScrollView()

Does nothing.

Static Functions

Instantiate()

	static BArchivable *Instantiate(BMessage *archive)

Returns a new BScrollView object, allocated by new and created with the version of the constructor that takes a BMessage archive. However, if the message doesn't contain data for an archived BScrollView object, Instantiate() returns NULL.

See also: BArchivable::Instantiate(), instantiate_object(), Archive()

Member Functions

Archive()

	virtual status_t Archive(BMessage *archive, bool deep = true) const

Calls the inherited version of Archive(), which will archive the target view and scroll bars if the deep flag is true. This function then adds the BScrollView's border style to the archive message.

See also: BArchivable::Archive(), Instantiate() static function

AttachedToWindow()

	virtual void AttachedToWindow(void)

Resizes scroll bars belonging to BScrollViews that occupy the right bottom corner of a document window (B_DOCUMENT_WINDOW) so that room is left for the resize knob. This function assumes that vertical scroll bars are B_V_SCOLL_BAR_WIDTH units wide and horizontal scroll bars are B_H_SCROLL_BAR_HEIGHT units high. It doesn't check to make sure the window is actually resizable.

This function also sets the default high color to a medium shade of gray.

See also: BView::AttachedToWindow()

Border() see SetBorder()

Draw()

	virtual void Draw(BRect updateRect)

Draws the border around the target view and scroll views, provided a border was requested when the BScrollView was constructed.

See also: the BScrollView constructor, BView::Draw()

IsBorderHighlighted() see SetBorderHighlighted()

ScrollBar()

	BScrollBar *ScrollBar(orientation posture) const

Returns the horizontal scroll bar if posture is B_HORIZONTAL and the vertical scroll bar if posture is B_VERTICAL. If the BScrollView doesn't contain a scroll bar with the requested orientation, this function returns NULL.

See also: the BScrollBar class

SetBorder() , Border()

	virtual void SetBorder(border_style border) border_style Border(void) const

These functions set and return the style of the BScrollView's border, which may be B_PLAIN_BORDER, B_FANCY_BORDER, or B_NO_BORDER. The border is originally set by the constructor. The three constants and the border's effect on the BScrollView are discussed there.

See also: the BScrollView constructor

SetBorderHighlighted() , IsBorderHighlighted()

	virtual status_t SetBorderHighlighted(bool highlighted) bool IsBorderHighlighted(void) const

SetBorderHighlighted() highlights the border of the BScrollView when the highlighted flag is true, and removes the highlighting when the flag is false. This function works by calling Draw(). However, it works only for a border in the B_FANCY_BORDER style. If successful, it returns B_OK. Otherwise, it returns B_ERROR.

IsBorderHighlighted() returns whether the border is currently highlighted. The return value is always false for a BScrollView that doesn't have a border or has only a "plain" one.

Highlighting a BScrollView's border shows that the target view is the current focus view for the window. Typically, the target view calls SetBorderHighlighted() from its MakeFocus() function when the focus changes. (The target knows that it's inside a BScrollView because of the TargetedByScrollView() notification it received.)

Archived Fields

The Archive() function adds the following fields to its BMessage argument:

Field	Type code	Meaning
"_style"	B_INT32_TYPE	Border type.

The following views are added to the "_views" field (deep copy only):

Name	Level	Meaning
target	0	Target view for the object.
"_VSB_"	0	Vertical BScrollBar.
"_HSB_"	0	Horizontal BScrollBar.

Some of these fields may not be present if the setting they represent isn't used, or is the default value. For example, if the border type is B_FANCY_BORDER, the "_style" field won't be found in the archive.