Derived from: public BView
Declared in: <interface/ScrollView.h>
A BScrollView object is a container for another view, a target view, typically a view that can be scrolled. The BScrollView creates and positions the scroll bars the target view needs and makes itself the parent of the scroll bars and the target view. It's a convenient way to set up scroll bars for another view.
If requested, the BScrollView draws a border around its children. Otherwise, it does no drawing and simply contains the family of views it set up.
The ScrollBar() function provides access to the scroll bars the BScrollView creates, so you can set their ranges and values as needed.
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)
Initializes the BScrollView. It will have a frame rectangle large enough to contain the target view and any scroll bars that are requested. If horizontal is true, there will be a horizontal scroll bar. If vertical is true, there will be a vertical scroll bar. Scroll bars are not provided unless you ask for them.
The border argument can be set to one of three values:
| B_PLAIN_BORDER | Draw a border consisting of just a simple line around the target view and scroll bars. |
A BScrollView can be used without scroll bars to simply contain and border the target view.
The BScrollView adapts its frame rectangle from the frame rectangle of the target view. It makes its frame just big enough to hold the target, scroll bars, and border. It positions itself so that the target view doesn't move within the window: If there's no border, its left and top sides are exactly where the left and top sides of the target view originally were. If there is a border, its sides are adjusted to make room for it while keeping the target view constant.
The target view is notified that it has become the target of a BScrollView with a TargetedByScrollView() function call. The BScrollView then adds the target view as its child along with any requested scroll bars. In the process, it modifies the target view's frame rectangle (but not its bounds rectangle) so that it will fit within its new parent.
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 container view whenever the container view is resized.
The scroll bars created by the BScrollView have an initial range extending from a minimum of 0 to a maximum of 1000. You'll generally need to ask for the scroll bars (using the ScrollBar() function) and set their ranges to more appropriate values.
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()
virtual ~BScrollView(void)
Does nothing.
static BScrollView *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()
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
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()
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()
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
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
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.) In the Interface Kit, only BListViews take the opportunity these functions afford to highlight a parent BScrollView's border.
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Last modified June 30, 1997.