picture saving added to camera example (#4842)

* camera click_pic added

* date formate corrected

* function name changed

* func name changed

* pep8 fixes

* pep8 fix

examples/camera/main.py

@@ -16,9 +16,10 @@ throw an exception during the kv language processing.
 
 from kivy.app import App
 from kivy.lang import Builder
-
-kv = '''
-BoxLayout:
+from kivy.uix.boxlayout import BoxLayout
+import time
+Builder.load_string('''
+<CameraClick>:
     orientation: 'vertical'
     Camera:
         id: camera
@@ -29,12 +30,30 @@ BoxLayout:
         on_press: camera.play = not camera.play
         size_hint_y: None
         height: '48dp'
-'''
+    Button:
+        text: 'Capture'
+        size_hint_y: None
+        height: '48dp'
+        on_press: root.capture()
+''')
+
+
+class CameraClick(BoxLayout):
+    def capture(self):
+        '''
+        Function to capture the images and give them the names
+        according to their captured time and date.
+        '''
+        camera = self.ids['camera']
+        timestr = time.strftime("%Y%m%d_%H%M%S")
+        camera.export_to_png("IMG_" + timestr)
+        print("Captured")
 
 
 class TestCamera(App):
+
     def build(self):
-        return Builder.load_string(kv)
+        return CameraClick()
 
 
 TestCamera().run()