选择OptionMenu中的选项时，如何使Tkinter按钮不消失？

Question

I have this code:

def type():
    variable=var.get()
    if variable=="Text with caps":
        import caps_main.py


from Tkinter import *
t = Tk()
t.geometry("500x300")
p = PhotoImage(file="C:\Users\Indrek\Downloads\Desert.gif")
l = Label(t, image=p)
t.wm_title("School Test")

var = StringVar(l)
var.set("Select test type.") # initial value

option = OptionMenu(l, var, "Text with caps", "Text with mistakes")
option.pack(expand=Y)


b = Button(l, text="Start", command = lambda:type())
b.configure(background='PeachPuff')
b.pack(expand=Y)

l.pack_propagate(0)
l.pack()

t.mainloop()

The problem is, when i run the code and select an option from optionmenu, the button "Start" disappears. How to make the button to not disappear?

When I change the code to:(widgets are in main frame(t) not in label(l) in this code)

def type():
    variable=var.get()
    if variable=="Text with caps":
        import caps_main.py


from Tkinter import *
t = Tk()
t.geometry("500x300")
p = PhotoImage(file="C:\Users\Indrek\Downloads\Desert.gif")
l = Label(t, image=p)
t.wm_title("School Test")

var = StringVar(t)
var.set("Select test type.") # initial value

option = OptionMenu(t, var, "Text with caps", "Text with mistakes")
option.pack(expand=Y)


b = Button(t, text="Start", command = lambda:type())
b.configure(background='PeachPuff')
b.pack(expand=Y)

l.pack_propagate(0)
l.pack()

t.mainloop()

Then everything works, but I dont want buttons to have such solid stripes for background. I want just buttons on my background image.

Answer 1

There are a couple of things that look suspicious in your code. First, you turn pack propagation off in the label. This means that the label won't resize based on the widgets inside the label. Thus, if your label is tiny, it will hide the menu that you've packed in the label. My guess is, that's what's happening. Without knowing the size of your image I can't say for certain.

The second problem is that when you pack the label in its container, you don't specify options such as expand and fill , so it won't grow to fill the main window.

If you're simply wanting to use a background image for your whole GUI, you don't have to add it to a label and then add all your widgets to the label. A simpler approach is to use place to have your label fill the main window, and then just pack or grid all the other widgets in the main window as normal. This is one case where place is a little better than grid or pack .