Widget Basics

The biggest change in appJar 1.0 is the introduction of a single function for ADDing, SETting and GETting widgets:

from appJar import gui 

def press(btnName):
    app.popUp("INFO", "You pressed " + btnName)

def update(value):
    if value == "list": app.slider("slider", app.listbox(value)[0])
    elif value == "slider": app.listbox("list", app.slider(value))
    app.label("display", app.listbox("list")[0])

# create the GUI
with gui("Version 1.0", bg="teal") as app:
    app.label("Version 1.0 Demo", colspan=2, bg="red")
    # group the buttons into a labelframe
    with app.labelFrame("Big Buttons", colspan=2, sticky="news", expand="both"):
        app.button("BUTTON A", press)
        app.button("BUTTON B", press)
        app.button("BUTTON C", press)
    app.listbox("list", [1, 2, 3, 4, 5], rows=5, selected=0, submit=update)
    app.label("display", "1", row=2, column=1, bg="yellow", sticky="news")
    app.slider("slider", colspan=2, range=(1,5), change=update, interval=1)

SimpleAppJar As can be seen, this has created a GUI, 7 widgets, and one container using 9 lines of code. All styling of the widgets has been done in the creation of the widget.


As demonstrated above, each widget now has a single function - the name of the widget.
Call this function passing one or both of the key parameters, to determine what should happen:

app.label("title", "text")      # ADD a label if the title is new
app.label("title", "text_2")    # SET a label if the title already exists
print(app.label("title"))       # GET a label if no widget is being added or set

Key Parameters

The two key parameters are:

Parameter Data type Description
title string A unique identifier for that widget type.
value string Any relevant information for the widget.

The logic is as follows:

Positional Parameters

When adding a widget, it is positioned in the first column of a new row.
If you want to change this, you can specify where it should go, either by naming the paramters:

app.label("title", "text", row=2, column=4, rowspan=3)      # ADD a label

Or by passing them as a tuple:

app.label("Main Title", pos=(1, 0))     # ADD a label in row 1, column 0
app.label("Sub Title", pos=(2, 0, 2))   # ADD a label in row 2, column 0, spanning 2 columns
Parameter Data type Default Description
row integer <next row> The grid row to place the widget in.
column integer 0 The grid column to place the widget in.
rowspan integer 1 The number of grid rows to stretch the widget across.
colspan integer 1 The number of grid columns to stretch the widget across.
pos list/tuple () Position parameters for the widget, in the order: row, column, colspan, rowspan

GUI Parameters

There are two GUI parameters which affect how widgets are displayed sticky and stretch.
These can be modified when adding a widget, just bear in mind they are GUI settings, and will affect all future widgets in the current container.

app.label("Title", sticky="", stretch="none")
app.label("SubTitle", sticky="ns", stretch="row")
Parameter Data type Default Description
sticky string <varies> Describes which sides the widget will stick to, one or more of: n, e, w, s in a single string.
stretch string <varies> Describes how the widget will stretch to fill the row/column: none, row, column or all.

Event Parameters

Most of the widgets also have some support for events (see the events page for more information).
submit & change will pass the name of the widget to the function, drop will pass the data to the function:
NB. the parameter should only be the name of the function, don't include any brackets.

def update(name):
    if name == "size":
    elif name == "toppings":

app.listbox("size", ["small", "medium", "large"], change=update)
app.listbox("toppings", ["corn", "cheese", "peppers"], change=update)
app.image("img1", "placeholder.gif", drop=True)
Parameter Data type Default Description
change function None A function to call when the widget is changed.
callFunction boolean True Set this to False, when setting the widget to stop the change function form being called.
submit function None A function to call when the widget is submitted.
over function (list) None A function to call when the mouse enters the widget, with an optional second function to call when the mouse leaves.
drop boolean/function None Update the widget with dropped data if True, otherwise call the function.
drag function (list) None A function to call call when the widget is dragged, with an optional second function to call when the widget is dropped.

Other Parameters

There are some other parameter that can be set on widgets.

Parameter Data type Default Description
label boolean/string False Adds a Label before the widget (only some input widgets), either the label's title or the the text of this parameter.
right string None Specify a premade right-click menu to link to the widget.
font integer/dict None Pass either a font size, or a dictionary of font properties to use for this widget's font.
focus boolean False Give keyboard focus to the widget.
tip string None Sets text to show in a mouse-over tooltip.