How to return string value of Console output to put it into a label in Tkinter

Question

I made a python script that has a lot of print statements showing what the program is doing rather than just having it just sit there and the python script works fine now I am creating a front end with tkinter. What I used to send the print statements to return them is some thing like this:

test.py
def PrintX():
    X = [1,2,3,4,5]
    for x in X:
        print(x)

My plan is to have a tkinter frame in that I put a label and set the text variable to my function in my script. My tkinter page script looks like this so far:

class TradingBotapp(tk.Tk):

    def __init__(self,*args,**kwargs):
        tk.Tk.__init__(self,*args,**kwargs)
        container = tk.Frame(self)
        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 (InitalSetup):
            frame = F(container,self)
            self.frames[F] = frame
            frame.grid(row=0,column=0,sticky='nsew')

        self.show_frame(InitalSetup)

    def show_frame(self,cont):
        frame = self.frames[cont]
        frame.tkraise()

class InitalSetup(tk.Frame):

    def __init__(self,parent,controller):
        tk.Frame.__init__(self,parent)
        label = tk.Label(self, text='Setup', font = LARGE_FONT).pack()
        Frame = tk.Frame(self,width=768,height=576).pack()
        lbl = tk.Message(Frame, text='').pack()
        button1 = ttk.Button(self, text='Start Setup',command=lambda:callback2(lbl)).pack()

def callback2(object):

    old_stdout = sys.stdout
    sys.stdout = StdoutRedirectorLabel(lbl)
    setup()
    #lbl['text'] = sys.stdout.result.strip()
    sys.stdout = old_stdout

class StdoutRedirectorLabel(object):

    def __init__(self,widget):
        self.widget = widget
        self.widget['text'] = ''

    def write(self, text):
        self.widget['text'] += text


app = TradingBotapp()
app.mainloop()

But nothing is showing up, but when I press the button I get self.widget['text'] = '' TypeError: 'NoneType' object does not support item assignment any help would be much appreciated

I got it I had to not pack and set it at the same time, by setting it then packing it on another line it worked — David Long, Oct 16 '19 at 20:43

score 0 · Answer 1 · answered Oct 11 '19 at 03:21

0

Haha... You've fallen victim to one of the classic blunders!! (In all seriousness, I've done this many times before, you're not alone) I believe you need to pack your labels with label1.pack() after their creation.

answered Oct 11 '19 at 03:21

Peter Matsakis

1
1

I have it at the end it has worked for me in other pages `label1 = tk.Label(Frame, textvariable=PrintX(), font = LARGE_FONT).pack()` – David Long Oct 11 '19 at 13:43
Sorry, I didn't see it on the end. Here's something to try though. I notice that you packed the frame for the setup label but you didn't pack InitalSetup. I don't know where you instantiate InitalSetup but try putting pack after that. – Peter Matsakis Oct 12 '19 at 14:51
I have that running upon button press of button1 `button1 = tk.Button(self, text='Start Setup',command=lambda:self.InitalSetup()).pack()` – David Long Oct 14 '19 at 15:53

score 0 · Answer 2 · answered Oct 16 '19 at 20:47

The problem was that lbl was set and packed at the same time. what was wrong: lbl = tk.Label(Frame, text='').pack() to fix it I had to do this instead:

lbl = tk.Label(Frame, text='') 
lbl.pack()

But it is not working the way I want it to so I have to find another way

How to return string value of Console output to put it into a label in Tkinter

2 Answers2