Tkinter / Python网格布局，按钮行跨度问题

Question

i'm trying to make this simple gui using grid layout where i have in one row a label an entry and a button, but for some reason the first button always takes the rowspan equal to the number of rows in previous column, even if i try to force it to have rowspan 1 it has no effect which makes me really confused.

import tkinter as tk
class MainApplication(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.grid()
        #LABELS
        self.l1 = tk.Label(self, text = "Source")
        self.l1.grid(column = 0, row = 0, sticky = "E")

        self.l2 = tk.Label(self, text = "Text files destination")
        self.l2.grid(column = 0, row = 1, sticky = "E")

        self.l3 = tk.Label(self, text = "Image files destination")
        self.l3.grid(column = 0, row = 2, sticky = "E")
        #ENTRIES
        self.e1 = tk.Entry(self)
        self.e1.grid(column = 1, row = 0)

        self.e2 = tk.Entry(self)
        self.e2.grid(column = 1, row = 1)

        self.e3 = tk.Entry(self)
        self.e3.grid(column = 1, row = 2)
        #BUTTONS

        self.b3 = tk.Button(text = "Select dir", command = self.cb2)
        self.b3.grid(column = 2, row = 0)

        self.b4 = tk.Button(text = "Select dir", command = self.cb2)
        self.b4.grid(column = 2, row = 1)

        self.b5 = tk.Button(text = "Select dir", command = self.cb2)
        self.b5.grid(column = 2, row = 2)


if __name__ == "__main__":
    root = tk.Tk()
    app = MainApplication(root)
    root.mainloop()

output: http://i.imgur.com/AdWkHwi.png

Answer 1

You don't specify a parent for the buttons, so their parent is the root window. The labels and entries, on the other hand, have their parent attribute set to the frame. What happens is that in the root , the frame is in row zero, and the first button is in row zero, and the height of the row is determined by the height of the frame.

The solution is to make the parent of the buttons be the frame.

    self.b3 = tk.Button(self, ...)
    self.b4 = tk.Button(self, ...)
    self.b5 = tk.Button(self, ...)