Magic Method Recipe: Building Tkinter Interfaces
================================================

Step 1
------
As we saw in the previous step, doing layout in Tkinter is painful. But using magic methods, we can build a wrapper library that makes Tkinter suck less:

.. sourcecode:: python

    frame = Frame [
        Button(text='One', side=TOP),
        Button(text='Two', side=TOP),
        Button(text='Tree', side=TOP),
    ]

Implement the ``__call__`` method of ``TkWrapper`` and the ``__getitem__`` method of ``ContainerWrapper``.    
    
.. sourcecode:: python

    import copy
    import Tkinter as tk
    from Tkinter import TOP, LEFT, BOTTOM, RIGHT

    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():
                if name is not 'side':
                    widget[name] = value                
            return widget

        def __call__(self, **kwargs):
            """Implement this method"""

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

        def __getitem__(self, children):
            """Implement this method"""

        def create_widget(self, parent):
            widget = super(ContainerWrapper, self).create_widget(parent)
            for child in self.children:
                childwidget = child.create_widget(widget)
                childwidget.pack(side=child.args['side'], padx=5, pady=5)                
            return widget

        def show(self, title='window'):
            root = tk.Tk()
            root.title(title)

            frame = self.create_widget(root)
            frame.pack()
                
            root.mainloop()
        
    Button = TkWrapper(tk.Button)
    Label = TkWrapper(tk.Label)
    Frame = ContainerWrapper(tk.Frame)

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

            Frame(side=TOP) [
                Button(text='Apple', side=LEFT),
                Button(text='Banana', side=LEFT),
                Button(text='Cranberry', side=LEFT),
            ],
            
            Button(text='Durian', side=BOTTOM),
        ]
        
        frame.show('A Cool Tkinter Example')

Expected output:

.. image:: tkinter-screenshot.png    

Hints:

.. class:: hintlist

#. You should be able to reuse a lot of the code from the previous recipe.
    
Solution: `tkinter1.py <solutions/tkinter1.py>`_

`Go to next step <step2.html>`_