LuaAPI/types/widget

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Revision as of 22:37, 27 September 2020 by Celtic Minstrel (talk | contribs) (Add some missing details about the API)

The widget userdata offers access to a widget of a GUI2 dialog. While there is only one type of widget userdata that covers all widgets including the window itself, the properties of a widget userdata are different for each type of widget. Indexing a widget's userdata can either be used to access a child widget or to set or get a property of a widget. Some properties are read-only; the properties depend on the type of the widget.

An example of accessing a child widget: 

function preshow(dialog)
  local okay_button = dialog.okay_button
  -- okay_button is now a handle to the the widgets child with the id 'okay_button' 
end

Widget Attributes

selected

  • widget.selected ↔ boolean
  • Available on: [toggle_button], [toggle_panel]

Whether the item is selected or not.

selected_index

  • widget.selected_index ↔ index
  • Available on: [listbox], [multi_page], [stacked_widget], [menu_button], [toggle_button], [toggle_panel]

The selected index of the item. For [toggle_button] and [toggle_panel], this is the same as selected only encoded as a number (0 or 1) instead of a boolean.

text

  • widget.text ↔ text
  • Available on: [text_box]

The text of the textbox.

value

  • widget.value ↔ position
  • Available on: [slider]

The current position of the slider.

percentage

  • widget.percentage ↔ position
  • Available on: [progress_bar]

The current position of the progress bar, between 0 and 1.

selected_item_path

  • widget.selected_item_path → array of indices
  • Available on: [treeview]

A table describing the currently selected node. If for example, in the following treeview, Item 9 is selected, the result will be {2,1,3}. 

+Section1
 +Subsection11
  *Item1
  *Item2
  *Item3
 +Subsection12
  *Item4
  *Item5
  *Item6
+Section2
 +Subsection21
  *Item7
  *Item8
  *Item9
 +Subsection22
  *Item10
  *Item11
  *Item12

path

  • widget.path → array of indices
  • Available on: [tree_view_node]

A table describing this node in the overall treeview. See selected_item_path for the meaning of the table..

unfolded

  • widget.unfolded ← boolean
  • Available on: [tree_view_node]

Control whether a tree node is currently expanded or not.

unit

  • widget.unit ← unit or unit type
  • Available on: [unit_preview_pane]

Change the displayed unit or unit type in the preview pane.

item_count

  • widget.item_count → number of items
  • Available on: [multi_page], listbox

The number of items in the container widget.

use_markup

  • widget.use_markup → boolean
  • Available on: Most widgets, in particular [label], [button]

Sets whether the widget's label will parse Pango formatting.

label

  • widget.label ← text
  • Available on: Most widgets, in particular [label], [button], [image]

The widget's label. Technically this is a special string used in the widget's wml definition. It usually does what one would expect, but also sets the image for image widgets.

marked_up_text

  • widget.marked_up_text ← text
  • Available on: Most widgets, in particular [label], [button]

Shortcut for setting label and use_markup=yes.

enabled

  • widget.enabled ← boolean
  • Available on: All widgets

tooltip

  • widget.tooltip ← text
  • Available on: All widgets

visible

  • widget.visible ← visibility string
  • Available on: All widgets

Determines whether the widget is visible onscreen. The following visibility statuses are recognized:

String value Boolean shorthand Meaning
visible true The widget is visible and handles events.
hidden The widget is not visible, doesn't handle events, but still takes up space on the dialog grid.
invisible false The widget is not visible, doesn't handle events, and does not take up space on the dialog grid.

type

  • widget.type → string
  • Available on: All widgets

Returns a string specifying the type of the widget.

Widget callbacks

on_modified

  • widget.on_modified ← function
  • Available on: Most widgets, in particular [slider], [toggle_button], [listbox], [menu_button], [text_box]

Triggers when the user changes the value of the widget.

on_left_click

  • widget.on_left_click ← function
  • Available on: All widgets

Triggers when the user clicks on the widget.

on_button_click

  • widget.on_button_click ← function
  • Available on: [button], [repeating_button]

Triggers when the user clicks on the button. This can differ from on_left_click, depending on the type of widget. For example, on a [repeating_button] it will fire multiple times if the user holds the mouse button down.

Widget methods

focus

  • widget:focus()

Switches the keyboard focus to the widget. This is often useful for dialogs containing a central listbox, so that it can be controlled with the keyboard as soon as it is displayed.

set_canvas

  • widget:set_canvas(layer index, content)

Sets the WML passed as the second argument as the canvas content (index given by the first argument) of the widget. The content of the WML table is described at GUICanvasWML. 

-- draw two rectangles in the upper-left corner of the window (assume dialog is the window widget)
dialog.set_canvas(2, {
    wml.tag.rectangle { x = 20, y = 20, w = 20, h = 20, fill_color= "0,0,255,255" },
    wml.tag.rectangle { x = 30, y = 30, w = 20, h = 20, fill_color = "255,0,0,255" }
})

The meaning of the canvas index depends on the chosen widget. It may be the disabled / enabled states of the widget, or its background / foreground planes, or... For instance, overwriting canvas 1 of the window with an empty canvas causes the window to become transparent.

add_item

  • widget:add_item([position]) → the new item, position

Add an item to a container widget, for example a listbox. Returns the created item as a widget userdata. You can pass a negative position to count from the end of the container, but the returned position is always positive.

add_item_of_type

  • widget:'add_item_of_type(category[, position]) → the new item, position

Add an item to a widget which is a heterogeneous container of different types of widgets, in particular multi_pages and treeviews. You can pass a negative position to count from the end of the container, but the returned position is always positive.

remove_items_at

  • widget:'remove_items_at(position)

Removes the widget at the given index of a container type widget (like treeviews).

find

  • widget:find(path, to, widget)

Finds a child widget of the widget of the given path. For example, here it searches for the widget with the id 'preview_panel' of the second item of the widget with the id 'unit_list': 

dialog:find(unit_list, 2, preview_panel)
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