Updating gui via callback using Gtk

Hi, I’m currently working on a GUI interface for PDE solver with Glk. This Interface should be very basic and just should it make more comfortable to play around with system parameters to reach the best results ffor images. The problem I have is very elementary but unfortunately not covered by the documentation. (See code below)

For my solver I have a file called parameters.jl which will be included at the beginning, it defines the values of e.g. x_min. These values are used in the algorithm and to label certain text fields in the GUI via set_gtk_property(name, :label, "string"). In order to change them, I would like to insert the new values in the text fields and they should be changed by hitting the button Start. Now the updated values should appear as the “new labels”.

To achieve this I use the callback function on_btn_start_clicked. The function can read out the value from the text field but it won’t set the variable e.g x_min to the new value and the GUI won’t be refreshed with the new value (it now should display the updated value for the next run).

(I just posted the relevant pieces of my code here.)


using Gtk


win = Window("PDE Solver", 1000, 1000)
g = Grid()

#current varable values
lbl_boxlength = set_gtk_property!(lbl_boxlength, :label, string("Boxlength=" , x_max - x_min))
lbl_gridpoints = set_gtk_property!(lbl_gridpoints, :label, string("Jx=",Jx))
lbl_timestep = set_gtk_property!(lbl_timestep, :label, string("dt=",dt))
lbl_ending_time = set_gtk_property!(lbl_ending_time, :label, string("T=",T))
lbl_epsilon = set_gtk_property!(lbl_epsilon, :label, string("epsilon=",epsilon))
lbl_current = GtkLabel("current values")
lbl_system_parameters = GtkLabel("System parameters")
lbl_new = GtkLabel("insert new values")

variable_x_min = Entry()
variable_x_max = Entry()
variable_gridpoints = Entry()
variable_timestep = Entry()
variable_ending_time = Entry()
variable_epsilon = Entry()


btn_start = GtkButton("Start")

# Cartesian coordinates, g[x,y]
g[3,1] = lbl_system_parameters
g[3,3] = lbl_current
g[4,3] = lbl_new

g[3,4] = lbl_boxlength
g[3,5] = lbl_gridpoints
g[3,6] = lbl_timestep
g[3,7] = lbl_ending_time
g[3,8] = lbl_epsilon

g[4,4] = variable_x_min
g[5,4] = variable_x_max
g[4,5] = variable_gridpoints
g[4,6] = variable_timestep
g[4,7] = variable_ending_time
g[4,8] = variable_epsilon

g[5,10] = btn_start

set_gtk_property!(g, :column_homogeneous, true)
set_gtk_property!(g, :column_spacing, 15)  # introduce a 15-pixel gap between columns
push!(win, g)

function on_btn_start_clicked(widget)
  str_x_min = get_gtk_property(variable_x_min,:text,String)
  x_min = parse(str_x_min)
  set_gtk_property!(lbl_boxlength, :label, string("Boxlength=" , x_min))

  solver() #this starts the solver routine


My version

Julia Version 1.3.0
Commit 46ce4d7933 (2019-11-26 06:09 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, skylake)
  JULIA_EDITOR = "C:\Users\Noobie\AppData\Local\atom\app-1.44.0\atom.exe"  -a

Here’s a small example of a button modifying an entry, is that what you want to do ?

using Gtk, Random

w = GtkWindow("")
entry = GtkEntry()

box = GtkBox(:v)
button = GtkButton("Randomize")


@guarded (nothing) function button_cb(widgetptr::Ptr, entry)
    @info entry.text[String] #reading entry
    entry.text[String] = Random.randstring(10) #writing entry

signal_connect(button_cb, button, "clicked", Nothing, (), false, entry)

Note that entry.text[String] is equivalent to get_gtk_property(entry, :text, String) (we should maybe document that better).

1 Like

Hi, thanks for your reply. It is close to, but I don’t want to rewrite the variable_gridpoints. Instead I want to update the label lbl_gridpoints and the variable Jx which is an integer in the paramters.jl file (since the new value of Jx should be used by the solver routine solver() )

The only not working part is to refresh win and to export the new value of Jx. Placing a return Jx in the callbackfunction only would produce a warning

(julia.exe:12460): Gtk-WARNING **: 21:43:49.315: Attempting to add a widget with type GtkGrid to a container of type GtkWindow, but the widget is already inside a container of type GtkWindow, please remove the widget from its existing container first.


using Gtk


win = GtkWindow("PDE", 1000, 1000)
g = GtkGrid()

#current varable values

lbl_gridpoints = GtkLabel(string("Jx=",Jx))

variable_gridpoints = GtkEntry()

btn_start = GtkButton("Start")

function button_cb(widgetptr::Ptr, variable_gridpoints)
     variable_gridpoints.text[String] #reading entry
     Jx = parse(Int,variable_gridpoints.text[String]) # setting the readed entrie to the variable Jx
     push!(win,g) # should refresh the label lbl_gridpoints
     solver() # solve the pde with the updated Jx
     #return Jx

signal_connect(button_cb, btn_start, "clicked", Nothing, (), false, variable_gridpoints)

g[3,5] = lbl_gridpoints

g[4,5] = variable_gridpoints

g[5,10] = btn_start

set_gtk_property!(g, :column_homogeneous, true)
set_gtk_property!(g, :column_spacing, 15)  # introduce a 15-pixel gap between columns
push!(win, g)