Fixed letters to only accept alpha characters, and convert them to up…

…per case.

Made app load GUI and push it to screen before loading letters, to give a smoother load-up experience. Also added logic to disable all controls on the screen during loading / processing, to further make it clear when the app is working.
Finally, went through and fixed some formatting issues that were bugging me.
The diff on this commit is a mess because I didn't do this in stages like a good programmer would.

countdown.py

@@ -5,115 +5,143 @@
 import collections
 import webbrowser
 
+
 class Countdown():
     def __init__(self):
-        with open(self._resource_path('words.txt')) as f:
-            words = [word.strip().lower() for word in f.readlines()]
-
-        self.words = dict(zip(words, [collections.Counter(word) for word in words]))
-
-        app_name = 'Countdown Tool'
-
+        app_name = 'Countdown'
+
         self.root = root = tk.Tk()
         root.title(app_name)
         root.geometry('345x315')
         root.minsize(345, 315)
         self._layout(root)
         root.iconbitmap(self._resource_path('icon.ico'))
-
+
+        root.after_idle(self._load_words)
+
         root.mainloop()
-
+
+    def _resource_path(self, relative):
+        if getattr(sys, 'frozen', False):
+            basedir = sys._MEIPASS
+        else:
+            basedir = os.path.dirname(__file__)
+
+        return os.path.join(basedir, relative)
+
+    def _load_words(self):
+        self.root.config(cursor='wait')
+        self._set_all_states(tk.DISABLED)
+        self.root.update()
+
+        with open(self._resource_path('words.txt')) as f:
+            words = [word.strip().lower() for word in f.readlines()]
+
+        self.words = dict(zip(words, [collections.Counter(word) for word in words]))
+
+        self.root.config(cursor='')
+        self._set_all_states(tk.NORMAL)
+
+    def _set_all_states(self, state, widget=None):
+        if widget is None:
+            widget = self.root
+
+        if 'state' in widget.config():
+            widget.configure(state=state)
+            return
+
+        for child in widget.winfo_children():
+            self._set_all_states(state, child)
+
     def _layout(self, root):
-        layoutFont = tkFont.Font(size = 18, weight = 'bold')
-        resultsFont = tkFont.Font(size = 12)
-        
+        layoutFont = tkFont.Font(size=18, weight='bold')
+        resultsFont = tkFont.Font(size=12)
+
         f = ttk.Frame(root)
-        f.pack(side = tk.TOP, fill = tk.X)
-
-        l = ttk.Label(f, text = 'Letters:', font = layoutFont)
-        l.pack(side = tk.TOP, anchor = tk.W)
-
-        eLetters = tk.Entry(f, font = layoutFont, validate = 'key')
-        vcmd = eLetters.register(self.validate_input)
-        eLetters.config(validatecommand = (vcmd, '%d', '%S'))
-        eLetters.pack(side = tk.TOP, fill = tk.X, expand = True)
+        f.pack(side=tk.TOP, fill=tk.X)
+
+        l = ttk.Label(f, text='Letters:', font=layoutFont)
+        l.pack(side=tk.TOP, anchor=tk.W)
+
+        sv = tk.StringVar()
+        sv.trace('w', lambda name, index, mode, sv=sv: self._on_text_changed(sv))
+        eLetters = tk.Entry(f, textvariable=sv, font=layoutFont, validate='key')
+        vcmd = eLetters.register(self._validate_input)
+        eLetters.config(validatecommand=(vcmd, '%d', '%S'))
+        eLetters.pack(side=tk.TOP, fill=tk.X, expand=True)
         eLetters.bind('<Control-a>', self._select_all)
         eLetters.focus()
-        
-        bCalculate = tk.Button(f, text = 'Calculate', font = layoutFont)
-        bCalculate.pack(side = tk.TOP, anchor = tk.W, fill = tk.X, expand = True)
-        
-        l = ttk.Label(f, text = 'Results:', font = layoutFont)
-        l.pack(side = tk.TOP, anchor = tk.W)
-        
+
+        bCalculate = tk.Button(f, text='Calculate', font=layoutFont)
+        bCalculate.pack(side=tk.TOP, anchor=tk.W, fill=tk.X, expand=True)
+
+        l = ttk.Label(f, text='Results:', font=layoutFont)
+        l.pack(side=tk.TOP, anchor=tk.W)
+
         f = ttk.Frame(root)
-        f.pack(side = tk.TOP, fill = tk.BOTH, expand = True)
-        
-        sb = ttk.Scrollbar(f, orient = tk.VERTICAL)
-        lResults = tk.Listbox(f, selectmode = tk.EXTENDED, yscrollcommand = sb.set, font = resultsFont)
-        sb.config(command = lResults.yview)
-        lResults.pack(side = tk.LEFT, fill = tk.BOTH, expand = True)
-        sb.pack(side = tk.RIGHT, fill = tk.Y)
-        
+        f.pack(side=tk.TOP, fill=tk.BOTH, expand=True)
+
+        sb = ttk.Scrollbar(f, orient=tk.VERTICAL)
+        lResults = tk.Listbox(f, selectmode=tk.EXTENDED, yscrollcommand=sb.set, font=resultsFont)
+        sb.config(command=lResults.yview)
+        lResults.pack(side=tk.LEFT, fill=tk.BOTH, expand=True)
+        sb.pack(side=tk.RIGHT, fill=tk.Y)
+
         lResults.bind('<Double-Button-1>', self._double_click)
-        
+
         calc = lambda x=None: self._show_results(eLetters, lResults)
-        bCalculate.configure(command = calc)
+        bCalculate.configure(command=calc)
         eLetters.bind('<Return>', calc)
-    
-    def validate_input(self, action, key):
-        if action == '1' and key not in 'abcdefghijklmnopqrstuvwxyz':
-            return False
-        
-        return True
-    
+
+    def _on_text_changed(self, sv):
+        sv.set(sv.get().upper())
+
+    def _validate_input(self, action, key):
+        return action != '1' or key.isalpha()
+
     def _select_all(self, event):
         event.widget.select_range(0, tk.END)
         return 'break'
-    
+
     def _double_click(self, event):
         widget = event.widget
         selection = widget.curselection()
         if not selection:
             return
-        
+
         value = widget.get(selection[0]).split(' ', 1)[1]
-        
+
         webbrowser.open('https://www.google.com/search?q=define+' + value, 2)
-    
+
     def _show_results(self, eLetters, lResults):
-        self.root.config(cursor = 'wait')
+        self.root.config(cursor='wait')
+        self._set_all_states(tk.DISABLED)
         self.root.update()
-
+
+        lResults.config(state=tk.NORMAL)
         lResults.delete(0, 'end')
-        
+
         for result in self._calculate(eLetters.get().strip()):
             lResults.insert('end', '(%d) %s' % (len(result), result))
-
-        self.root.config(cursor = '')
-
+
+        self.root.config(cursor='')
+        self._set_all_states(tk.NORMAL)
+
     def _calculate(self, letters):
         if not letters:
             return []
-        
+
         results = []
         letters = collections.Counter(letters.lower())
-        
+
         for word, word_letters in self.words.items():
             difference = collections.Counter(letters)
             difference.subtract(word_letters)
             if not any(val < 0 for val in difference.values()):
                 results.append(word)
-
-        return sorted(results, key = len, reverse = True)
-
-    def _resource_path(self, relative):
-        if getattr(sys, 'frozen', False):
-            basedir = sys._MEIPASS
-        else:
-            basedir = os.path.dirname(__file__)
 
-        return os.path.join(basedir, relative)
+        return sorted(results, key=len, reverse=True)
+
 
 if __name__ == '__main__':
     Countdown()