GUI component interaction: Difference between revisions

=={{header|R}}==

<lang julia>

using Tk

w = Toplevel("Component Interaction Example")

fr = Frame(w)

pack(fr, {:expand=>true, :fill => "both"})

## The task: For a minimal "application", write a program that

## presents a form with three components to the user: A numeric input

## field ("Value") and two buttons ("increment" and "random").

value = Entry(fr, "")

increment = Button(fr, "Increment")

random = Button(fr, "Random")

formlayout(value, "Value:")

formlayout(increment, " ")

formlayout(random, " ")

set_value(value, "0") ## The field is initialized to zero.

tk_bind(increment, "command") do path ## increment its value with the "increment" button.

val = get_value(value) | float

set_value(value, string(val + 1))

end

function validate_command(path, P)

try

if length(P) > 0 parsefloat(P) end

tcl("expr", "TRUE")

catch e

tcl("expr", "FALSE")

end

end

function invalid_command(path, W)

println("Invalid value")

tcl(W, "delete", "@0", "end")

end

tk_configure(value, {:validate=>"key", :validatecommand=>validate_command, :invalidcommand=>invalid_command })

## Pressing the "random" button presents a confirmation dialog, and resets the field's value to a random value if the answer is "Yes".

tk_bind(random, "command") do path

out = Messagebox(w, "Randomize input", "Select a new random number?")

if out == "ok"

new_value = floor(100*rand(1))[1]

set_value(value, string(new_value))

end

end

</lang>