From 79ef354b73f2d40e48fb47d51288d8896b3414ac Mon Sep 17 00:00:00 2001
From: renzon <renzon@gmail.com>
Date: Tue, 11 Apr 2017 16:32:17 -0300
Subject: [PATCH] Adicionado exemplo do Timer

Isso fica de acordo com link nos slides do curso
---
 exemplos/__init__.py |  0
 exemplos/timer.py    | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 exemplos/__init__.py
 create mode 100644 exemplos/timer.py

diff --git a/exemplos/__init__.py b/exemplos/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/exemplos/timer.py b/exemplos/timer.py
new file mode 100644
index 0000000..ae7db19
--- /dev/null
+++ b/exemplos/timer.py
@@ -0,0 +1,36 @@
+from tkinter import Frame, Label, Button
+
+
+class Timer(Frame):
+    def __init__(self):
+        super().__init__()
+        self.inicio = self.agora = 15
+        self.pendente = None  # alarme pendente
+        self.grid()
+        self.mostrador = Label(
+            self, width=2, anchor='e', font='Helvetica 120 bold')
+        self.mostrador.grid(column=0, row=0, sticky='nswe')
+        self.bt_start = Button(self, text='Start', command=self.start)
+        self.bt_start.grid(column=0, row=1, sticky='we')
+        self.atualizar_mostrador()
+
+    def atualizar_mostrador(self):
+        self.mostrador['text'] = str(self.agora)
+
+    def start(self):
+        if self.pendente:
+            self.after_cancel(self.pendente)
+        self.agora = self.inicio
+        self.atualizar_mostrador()
+        self.pendente = self.after(1000, self.tictac)
+
+    def tictac(self):
+        self.agora -= 1
+        self.atualizar_mostrador()
+        if self.agora > 0:
+            self.pendente = self.after(1000, self.tictac)
+
+
+if __name__ == '__main__':
+    timer = Timer()
+    timer.mainloop()