Magic Method Recipe: Building Tkinter Interfaces

Step 2

We still have not succeeded at making Tkinter layout not suck. That is because we still have to specify which side to pack each widget. Instead, it would be nice to have widget containers that know which side to pack their child widgets on:

# Pack everything from the top
frame = VFrame [
    Button(text='One'),
    Button(text='Two'),
    Button(text='Tree'),
]

Implement the ContainerWrapper class to accomodate this functionality.

import copy, Tkinter as tk

class TkWrapper(object):
    def __init__(self, cls):
        self.cls = cls
        self.args = {}

    def create_widget(self, parent):
        widget = self.cls(parent)
        for name, value in self.args.items():
            widget[name] = value
        return widget

    def __call__(self, **kwargs):
        wrapper = copy.deepcopy(self)
        wrapper.args.update(kwargs)
        return wrapper

class ContainerWrapper(TkWrapper):
    """Implement this class"""

Button = TkWrapper(tk.Button)
Label = TkWrapper(tk.Label)
HFrame = ContainerWrapper(tk.Frame, tk.LEFT)
VFrame = ContainerWrapper(tk.Frame, tk.TOP)

if __name__ == '__main__':
    frame = VFrame [
        Button(text='One'),
        Button(text='Two'),
        Button(text='Tree'),

        HFrame [
            Button(text='Apple'),
            Button(text='Banana'),
            Button(text='Cranberry'),
        ],

        Button(text='Durian')
    ]

    frame.show('A Cool Tkinter Example')

Expected output:

Hints

1. You can reuse a lot of code from the solution to the previous step.

2. You will use the following line in your solution: def __init__(self, cls, side):.

3. This is what your __init__ method should look like:

   def __init__(self, cls, side):
       super(ContainerWrapper, self).__init__(cls)
       self.side = side
       self.children = []
   

4. The create_widget method needs to take advantage of the self.side attribute.

5. You will use the following line in your solution: childwidget.pack(side=self.side, padx=5, pady=5).

Solution: solutions/tkinter2.py

Go back