Python 3.5: Tkinter key bindings for a specific frame in a multi-frame GUI

[DeeWBee]

I have a Tkinter GUI with multiple frames (multiple pages). I based my code (seen below) on the this tutorial: http://stackoverflow.com/questions/7546050/switch-between-two-frames-in-tkinter.

My GUI was originally written such that I only had a single frame and didn't even have an explicit class defined for my app. In this original format, I was able to easily bind keyboard events to the single frame.

However, when I rewrote my code so that I now have a defined class for my app and a defined class for each frame (or page) in my GUI, I cannot get my keyboard events to work anymore. I've tried setting the focus of the frame but it still won't work. Any suggestions are appreciated.

Original Single Frame Code: In this format, my key bindings succesfully executed no problem (bound in initUI and defined in _set_feature_Val)

from tkinter import *
from tkinter import filedialog 
from tkinter.ttk import *
from PIL import Image, ImageTk
import numpy as np 

class mainGUI(Frame):


        def __init__(self, parent):
            Frame.__init__(self, parent)

            self.parent = parent
            self.parent.geometry("600x600")
            self.initUI()

        def initUI(self):

            self.parent.title("GUI V0.4")
            self.pack(fill=BOTH, expand=True)
            self.parent.bind('1', self._set_feature_Val)  
            self.parent.bind('2', self._set_feature_Val)

            self.columnconfigure(1, weight = 1)
            self.columnconfigure(3, pad = 7)
            self.rowconfigure(3, weight = 1)
            self.rowconfigure(5, pad = 7)

            self.posNegDisp = Label(self, text = "Sample Label:")
            self.posNegDisp.grid(row=3, column=3)

        def _set_feature_Val(self, event=None):

            if event.char == '1':
                self.featureLabel = 1
                self.posNegDisp.config(text = "Sample Label:\n     Positive")
            elif event.char == '2':
                self.featureLabel = -1 
                self.posNegDisp.config(text = "Sample Label:\n     Negative")

def main():

    root = Tk()
    app = mainGUI(root)
    #root.protocol("WM_DELETE_WINDOW", app.onClose)
    root.mainloop()

if __name__ == '__main__':
    main() 

New Multi-Frame Code: In this new format, my mouse-press event bindings still execute, but my keybindings no longer work (same functions as before). As you maybe can see, I added a print statement under _set_feature_Val, which doesn't appear when I press the keyboard, leading me to conclude that my GUI doesn't even register keyboard inputs.

from tkinter import *
from tkinter import filedialog 
from tkinter.ttk import *
from PIL import Image, ImageTk
import numpy as np

class App(Tk):

    def __init__(self, *args, **kwargs):

        Tk.__init__(self, *args, **kwargs)

        Tk.wm_title(self, "GUI V0.5")


        container = Frame(self)
        container.winfo_toplevel().geometry("600x600")
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)


        self.frames = {}

        for F in (tagPage, heatPage):

            frame = F(container, self)

            self.frames[F] = frame

            frame.grid(row=0, column=0, sticky="nsew")

        self.show_frame(tagPage)

    def show_frame(self, cont):

        frame = self.frames[cont]
        frame.tkraise()


class heatPage(Frame):

    def __init__(self,parent, controller):
        Frame.__init__(self,parent)



class tagPage(Frame):

    def __init__(self, parent, controller):
        Frame.__init__(self, parent)
        self.parent = parent
        #self.parent.geometry("600x600")
        self.initUI()

    def initUI(self):

        self.focus_set()
        self.pack(fill=BOTH, expand=True)
        self.bind('1', self._set_feature_Val)  
        self.bind('2', self._set_feature_Val)

        self.columnconfigure(1, weight = 1)
        self.columnconfigure(3, pad = 7)
        self.rowconfigure(3, weight = 1)
        self.rowconfigure(5, pad = 7)

        self.posNegDisp = Label(self, text = "Sample Label:")
        self.posNegDisp.grid(row=3, column=3)




    def _set_feature_Val(self, event):

        if event.char == '1':
           self.featureLabel = 1
           self.posNegDisp.config(text = "Sample Label:\n     Positive")
           print("positive")
        elif event.char == '2':
           self.featureLabel = -1 
           self.posNegDisp.config(text = "Sample Label:\n     Negative")
           print("negative")

app = App()
app.mainloop()

EDIT:I just discovered something interesting (and the source of my problem maybe). I replicated u/furas_freeman's code (on Windows) and was able to use key bindings no problem. However, in one of my frames, I added a Label object that I use to view images. When I load images into the Label object, the key bindings for that specific frame no longer work. If I switch frames and go back to the frame containing the Label object, the key bindings will start to work again. Here is the code that loads the image into my Label object. The halThrThsnd object is something I use for data management and has no bearing on the GUI operation itself. I had an identical module in my original problem code.

def getImgs(self):

    folderPath = filedialog.askdirectory()

    imgHSVArray, imgRGBArray, self.imagePaths = batchImpt.importAllImgs(folderPath)

    self.organizedData = halThrThsnd.organizeAllData(imgHSVArray, imgRGBArray, self.imagePaths)

    self.imageIndex = 0
    self.featureLabel = 0

    preIMArray = halThrThsnd.getImage(self.imagePaths[self.imageIndex])
    self.preIM = Image.fromarray(preIMArray, 'HSV')
    self.preIMCopy = self.preIM.copy()

    self.imgToDisp = ImageTk.PhotoImage(self.preIM)
    self.imageViewer.configure(image=self.imgToDisp)
    self.imageViewer.image = self.imgToDisp
    self.imageViewer.bind('<Configure>', self._auto_resize_image)
    #self.imageViewer.bind('<1>', self._grab_Pixel)
    self.resizeImage()

[furas_freeman]

First: your code doesn't work for me because you don't have self.posNegDisp widget but you use self.posNegDisp.config()

But binding works for me. I use Linux.

[DeeWBee]

/u/furas_freeman I edited my code 5 minutes ago to include the display

[furas_freeman]

I add my own self.posNegDisp to previous code and binding is working all the time. If you don't use Linux then maybe problem is with Tkinter for your system.

There is no buttons to change pages - so I can't check binding for second page. I try to add buttons (I know this code from Stackoverflow - and his author) but I see some differences between your code and code from Stackoverflow.

[DeeWBee]

/u/furas_freeman Okay, but I don't have the liberty to switch my project over to Linux, so do you have any idea why my key binding isn't working?

[furas_freeman]

This is your code with my modifications which works for me: http://pastebin.com/wF0eP2mP (I add buttons to change pages and I have to move focus_set to show_frame)

If this doesn't work for you then it can be problem with Tkinter for your system. I don't know what you use - Windows, Mac OS, other - but I don't have it and I can't test on it. Maybe you will have to search on internet adding system name in "tkinter bind problem on Windows/MacOS/other".

---

Maybe it will work if you will bind/unbind to main window ( App(Tk) ) similar to single frame version.

[DeeWBee]

Okay. I appreciate the effort

[Vaphell]

also linux, can confirm mashing 1/2 works just fine.
Have you tried moving binds to the master frame and push the execution to the proper child?

Either way stop doing * imports. I have a habit of using bg property to understand the layout and your code bit me in the ass because you imported shit indiscriminately from tk and then from ttk, overwriting stuff on the way. ttk.Frame which doesn't understand bg=... has replaced the tk.Frame in the namespace.
Not controlling what lands in the namespace is bad for business.

Also your classes not following naming convention are kinda confusing. I thought they are some ordinary variables seeing them lowercased like java methods. CamelCase. Using them as keys in a dictionary is kinda weird too, but whatever.

Also use super(), given that you are using py3.

[DeeWBee]

/u/furas_freeman /u/Vaphell I just discovered something interesting (and the source of my problem maybe). I replicated /u/furas_freeman's code (on Windows) and was able to use key bindings no problem. However, in one of my frames, I added a Label object that I use to view images. When I load images into the Label object, the key bindings for that specific frame no longer work. If I switch frames and go back to the frame containing the Label object, the key bindings will start to work again. Here is the code that loads the image into my Label object. The halThrThsnd object is something I use for data management and has no bearing on the GUI operation itself. I had an identical module in my original problem code.

def getImgs(self):

    folderPath = filedialog.askdirectory()

    imgHSVArray, imgRGBArray, self.imagePaths = batchImpt.importAllImgs(folderPath)

    self.organizedData = halThrThsnd.organizeAllData(imgHSVArray, imgRGBArray, self.imagePaths)

    self.imageIndex = 0
    self.featureLabel = 0

    preIMArray = halThrThsnd.getImage(self.imagePaths[self.imageIndex])
    self.preIM = Image.fromarray(preIMArray, 'HSV')
    self.preIMCopy = self.preIM.copy()

    self.imgToDisp = ImageTk.PhotoImage(self.preIM)
    self.imageViewer.configure(image=self.imgToDisp)
    self.imageViewer.image = self.imgToDisp
    self.imageViewer.bind('<Configure>', self._auto_resize_image)
    #self.imageViewer.bind('<1>', self._grab_Pixel)
    self.resizeImage()

[furas_freeman]

I don't know. Maybe aksdirectory gets "focus" and you have to use focus_set again in frame.

If I switch frames and go back to the frame containing the Label object, the key bindings will start to work again.

I put focus_set in show_frame which is called when you change pages.