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ANSIScrollingListBoxPane

ANSIScrollingListBoxPane Class

An ANSIScrollingListBoxPane object is similar to an ANSIListBoxPane; it displays a list of items in a text mode terminal or xterm and allows the user to use the terminal’s Cursor-Up/Cursor-Down keys, Emacs compatible C-n/C-p keys, or vi compatible j/k keys to select an item in the list.

Pressing Enter or Escape closes the widget. An application can retrieve the selected item’s text with the selectedText method, which is described below.

In addition, an ANSIScrollingListBoxPane object can scroll the list if the number of items is greater than the height of the widget’s viewable area, in order to keep the selected item visible. The widget also displays a read-only scroll bar that indicates which portion of the list is visible. 


int main () {
  ANSIScrollingListBoxPane new sListBox;

  sListBox enableExceptionTrace;

  sListBox withShadow;
  sListBox noBorder;    /* Not all terminals support line 
                           drawing characters.            */

  sListBox appendLine "Item 1";
  sListBox appendLine "Item 2";
  sListBox appendLine "Item 3";
  sListBox appendLine "Item 4";
  sListBox appendLine "Item 5";
  sListBox appendLine "Item 6";
  sListBox appendLine "Item 7";
  sListBox appendLine "Item 8";
  sListBox appendLine "Item 9";
  sListBox appendLine "Item 10";
  sListBox appendLine "Item 11";
  sListBox appendLine "Item 12";
  sListBox appendLine "Item 13";
  sListBox appendLine "Item 14";
  sListBox appendLine "Item 15";
  sListBox appendLine "Item 16";
  sListBox appendLine "Item 17";
  sListBox appendLine "Item 18";
  sListBox appendLine "Item 19";
  sListBox appendLine "Item 20";
  sListBox appendLine "Item 21";
  sListBox appendLine "Item 22";
  sListBox appendLine "Item 23";
  sListBox appendLine "Item 24";
  sListBox appendLine "Item 25";
  sListBox appendLine "Item 26";
  sListBox appendLine "Item 27";
  sListBox appendLine "Item 28";
  sListBox appendLine "Item 29";
  sListBox appendLine "Item 30";
  sListBox appendLine "Item 31";
  sListBox appendLine "Item 32";

  sListBox show 5, 6;

  printf ("%s\n", sListBox selectedText);

  sListBox cleanup;
}

Instance Variables

items

A List of the items that the receiver displays. See List.

oldSelectedContent

An ANSILabelPane object that contains previously selected item. See ANSILabelPane.

prevSelectedLine

An Integer that contains the index of the previously selected item. See Integer.

selectedContent

An ANSIScrollPane object that draws the widget’s scroll bar. See ANSIScrollPane.

selectedContent

An ANSILabelPane object that contains selected item. See ANSILabelPane.

selectedLine

An Integer that contains the index of the selected item. See Integer.

totalLines

An Integer that contains total number of list items. See Integer.

viewStartLine

An Integer that specifies which item begins the list’s viewable portion. See Integer.

viewHeight

An Integer that contains the height in text lines of the widget’s visible area. See Integer.

viewWidth

An Integer that contains the height in character columns of the widget’s visible area. See Integer.

Instance Methods

appendLine (String item_text)

Adds item_text to the list’s contents.

cleanup (void)

Deletes the display buffers associated with the list box and scroll bar.

handleInput (void)

Waits for the user’s input. Changes the selected item when the user cursors through the list using the terminal’s cursor keys, Emacs compatible C-n/C-p, or vi compatible j/k. Restores the terminal and returns when the user presses Enter or Escape.

noBorder (void)
withBorder (void)

Set or unset the border for the main scroll pane and the scroll bar. These methods are equivalent to the following expressions. 


  /* To display borders. */
  listPane border = 1;
  listPane scrollBar border = 1;

  /* To hide the borders. */
  listPane border = 0;
  listPane scrollBar border = 0;

Note that not all terninals support line drawing characters.

noBorder (void)
withBorder (void)

Set or unset the shadow for the main scroll pane and the scroll bar. The methods are a shortcut for these statements. 


  /* To display shadows. */
  listPane shadow = 1;
  listPane scrollBar shadow = 1;

  /* To hide the shadows. */
  listPane shadow = 0;
  listPane scrollBar shadow = 0;
new (String object_name)

Constructs a new ANSIScrollingListBoxPane for each label given in the argument list. Sets the dimensions for the viewable areas, decorations, and creates the display buffers for the list box and the scroll bar.

refresh (void)

Redraws the list box.

refreshSelection (void)

Un-highlights the previously selected item and highlights the currently selected item.

refreshSelectionFirst (void)

Highlights the currently selected item, which is normally the first item in the list when first drawing the widget–i.e., when there is no previously selected item.

scrollThumbSize (void)

Sets the scrollBar instance variable’s thumbHeight instance variable based on which portion of the list is visible. See ANSIScrollPane.

scrollThumbStart (void)

Sets the scrollBar instance variable’s thumbStartLine instance variable based on which portion of the list is visible. See ANSIScrollPane.

selectedText (void)

Returns a String containing the text of the selected item. See String.

selectNext (void)

Sets the next selectedLine and selectedContent instance variables to the next item in the list. If the selected item is already the last item in the list, the method does nothing.

selectPrev (void)

Sets the next selectedLine and selectedContent instance variables to the previous item in the list. If the selected item is already the first item in the list, the method does nothing.

show (Integer x, Integer y)

Displays the widget an character row and column x,y on the terminal display, then calls the handleInput method to process user input.

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