StringBrowser 3I "30 November 1989" "InterViews" "InterViews Reference Manual"

Table of contents


NAME

StringBrowser - browse and/or select items in a list

SYNOPSIS

#include

DESCRIPTION

StringBrowser is an interactor that provides a browsing and selection interface to a list of strings. StringBrowsers are often used in dialog boxes to let the user browse and select from an unbounded set of textual entries. A StringBrowser displays the list of strings and provides several ways to scroll the list. The user selects strings with either the mouse or the keyboard; the StringBrowser can restrict selection to a single string or allow multiple selections. The application queries the StringBrowser for the selected string(s).

A StringBrowser contains no entries initially; strings are appended consecutively or in random order, and they can be removed in any order. The strings are accessed with a string index from 0 to n-1, where n is the total number of strings. The StringBrowser maintains a separate list of strings that have been selected; these strings are accessed with a selection index from 0 to m-1, where m is the total number of selected strings.

Left-clicking inside the StringBrowser (or calling the Browse function) makes it interpret subsequent keyboard events as scrolling or selection operations on the entries. StringBrowser relinquishes control when it detects a click outside its canvas or when it receives a predetermined escape character.

Middle-clicking inside the StringBrowser lets the user ``grab-scroll'' the entries. During grab-scrolling, the StringBrowser scrolls the entries to follow the mouse position, making it appear as though the user is dragging the entries themselves. Right-clicking engages ``rate-scrolling,'' a joy-stick-like scrolling interface in which the scrolling rate increases as the user drags the mouse away from the initial click point. For example, dragging the mouse downwards after the initial click scrolls the browser downwards at an increasing rate; dragging upwards thereafter reduces the rate until scrolling stops entirely at the initial click point. Dragging up beyond this point makes the browser scroll in the reverse direction.


KEY BINDINGS

Below are the key bindings for browsing and selection commands:

Go to the first string.

Go to the last string.

Select all.

Unselect all.

Select previous string.

Select next string.

Select topmost-visible string.

Select bottommost-visible string.

Scroll down one string.

Scroll up one string.

Scroll down one screenful.

Scroll up one screenful.

Scroll down one-half screenful.

Scroll up one-half screenful.


PUBLIC OPERATIONS

StringBrowser(ButtonState*, int rows, int cols, boolean uniqueSel,
int highlight, const char* done)"
StringBrowser(const char* name, ButtonState*, int, int,
boolean, int, const char*)" Create a new StringBrowser object. The StringBrowser will use the ButtonState to communicate the result of browsing operations. The StringBrowser bases its shape on the rows and cols parameters: the height equals rows multiplied by the font height, and the width equals cols multiplied by the width of an average character. The uniqueSel parameter specifies whether or not selection is limited to one string (the default), and the highlight parameter specifies the appearance of selected strings (Reversed by default). Typing any character in the string done will make the StringBrowser stop interpreting keyboard events; the ButtonState is set to this terminating character as a side-effect. A double left-click inside the StringBrowser is equivalent to a single left-click selection followed by a key press that generates the first character in done. To be interpreted as a double-click, two clicks must occur not more than clickDelay milliseconds apart. The default click delay is 250 ms; a different value can be specified via the "clickDelay" user-preference attribute.
void Browse()
Initiate browsing. Subsequent keypresses will be interpreted as browsing and selection commands according to the key bindings listed above.
void Insert(const char* string, int index)
Insert string at position index. StringBrowser makes a copy of the string for internal use.
void Append(const char* string)
Insert a copy of string after the last string.
void Remove(int index)
Remove the string at position index, moving subsequent strings up to fill the gap.
int Index(const char* string)
Return the index of the first string that matches string.
char* String(int index)
Return the string at the given index.
int Count()
Return the total number of strings in the StringBrowser.
void Clear()
Remove all strings from the StringBrowser.
void Select(int index)
void Unselect(int index)
Select (unselect) the string at the given index. The string will be redrawn in the appropriate style. If multiple selections are not allowed and an another string has been selected already, then selecting a new string will unselect the original string.
void SelectAll()
void UnselectAll()
Select (unselect) all strings. SelectAll does nothing if multiple selections have been disallowed.
int Selection(int n)
Return the string index of the nth selected string.
int SelectionIndex(int n)
Return the selection index of the nth string.
int Selections()
Return the total number of selected strings.
boolean Select(int n)
Return whether the nth string has been selected.

SEE ALSO

Interactor(2I), Button(3I)