how to remove previous input and only show current input in key binding of python-CodePudding

say if you input 123 then 456, the program will gives you the following result: "Weight is: 123g" "Weight is: 456g"

how to code so that it only gives me the current result with previous result being removed. "Weight is: 456g"

from tkinter import *
  
# Create a GUI app
app = Tk()
  
# Set the title and geometry of the app
app.title('Bind Number Keys')
app.geometry("800x400")
reading = ''  


# Make a function to display a message
# whenever user presses 0-9 key
def key_press(self):
    global reading
    if (self.keysym == 'Return' or self.keysym == 'KP_Enter'):
        if reading != '':
            Label(app, text="Weight is: "   reading   'g', font='Arial 16 bold').pack()
            reading = ''
    else:
        reading  = self.char    
    
# Create a label widget to display the text
label = Label(app, text="Key in your weight")
label.pack(pady=25)
label.config(font='Arial 20 bold')
  
# Bind all the number keys with the callback function
#for i in range(10):
#   app.bind(str(i), key_press)
app.bind_all('<Key>', key_press)

# Make infinite loop for displaying app on the screen
app.mainloop()

CodePudding user response：

Instead of creating a new label on each user entry create a label only once and update the text= property of the label to the current value with .config(). You don't need to remove/destroy the label and create a new one each time you need to show a new text in the label or change other label properties. See the code below where the label is created only once and updates its text according to user input:

# https://stackoverflow.com/questions/72614933/how-to-remove-previous-input-and-only-show-current-input-in-key-binding-of-pytho
from tkinter import *
  
# Create a GUI app
app = Tk()
  
# Set the title and geometry of the app
app.title('Bind Number Keys')
app.geometry("800x400")
reading = ''  
objLabel = None

# Make a function to display a message
# whenever user presses 0-9 key
def key_press(self):
    global reading, objLabel
    if (self.keysym == 'Return' or self.keysym == 'KP_Enter'):
        if reading != '':
            if objLabel is None:
                objLabel = Label(app, text="Weight is: "   reading   'g', font='Arial 16 bold')
                objLabel.pack()
            else: 
                objLabel.config(text="Weight is: "   reading   'g')
        reading = ''
    else:
        reading  = self.char    
    
# Create a label widget to display the text
label = Label(app, text="Key in your weight")
label.pack(pady=25)
label.config(font='Arial 20 bold')
  
# Bind all the number keys with the callback function
#for i in range(10):
#   app.bind(str(i), key_press)
app.bind_all('<Key>', key_press)

# Make infinite loop for displaying app on the screen
app.mainloop()

CodePudding user response：

It will work

from tkinter import *
  
# Create a GUI app
app = Tk()
  
# Set the title and geometry of the app
app.title('Bind Number Keys')
app.geometry("800x400")
reading = ''  


# Make a function to display a message
# whenever user presses 0-9 key
label = Label(app, text="Key in your weight")
label.pack(pady=25)

my_label = Label(app, font='Arial 16 bold')
my_label.pack()
def key_press(self):
    global reading
    if (self.keysym == 'Return' or self.keysym == 'KP_Enter'):
        if reading != '':
            t = "Weight is: "   reading   'g'
            my_label.config(text=t)
            app.update()
            reading = ''
    else:
        reading  = self.char    
# Create a label widget to display the text

label.config(font='Arial 20 bold')
  
# Bind all the number keys with the callback function
#for i in range(10):
#   app.bind(str(i), key_press)
app.bind_all('<Key>', key_press)

# Make infinite loop for displaying app on the screen
app.mainloop()