Added start/stop button for autoplay

indicators.py

@@ -845,6 +845,7 @@ if __name__ == "__main__":
     # App layout
     app.layout = [
         html.Button('Refresh Data', id='button', n_clicks=0),
+        html.Button('Auto Play', id="start-button", n_clicks=0, disabled=True),
         # html.Div(children='Pick A Symbol from Dropdown List: '),
         # html.Hr(),
         # dcc.RadioItems(options=['pop', 'lifeExp', 'gdpPercap'], value='lifeExp', id='controls-and-radio-item'),
@@ -860,12 +861,28 @@ if __name__ == "__main__":
         dcc.Interval(
             id='interval-component',
             interval=3*1000, # in milliseconds
-            n_intervals=0
-        )        
+            n_intervals=0,
+            disabled=True,
+        ),
     ]
 
+    # start button callback
+    @callback(Output('interval-component', 'disabled'),
+            Output("start-button", "children"),
+            Input("start-button", "n_clicks"))
+    def start_cycle(n):
+        if n:
+            if n%2 == 0:
+                return True, "Auto Play"
+            else:
+                return False, "Pause"
+        return no_update
+    
+    # interval callback
     @callback(Output('controls-and-radio-item', 'value'), Input("interval-component", "n_intervals"))
     def cycle_syms(n):
+        # if not n:
+        #     return no_update
         syms=["AMZN", "GOOGL", "AAPL", "SPY"]
         return syms[n % 4]
 
@@ -874,8 +891,8 @@ if __name__ == "__main__":
         j_obj = intelligent_loop_plots()
         return j_obj
 
-    # button callback
-    @app.callback(
+    # retrieve data button callbacks
+    @callback(
         Output("button", "disabled", allow_duplicate=True),
         Input("button", "n_clicks"),
         prevent_initial_call=True,
@@ -916,6 +933,7 @@ if __name__ == "__main__":
     @callback(
         Output(component_id='controls-and-radio-item', component_property='options'),
         Output(component_id='button', component_property='disabled'),
+        Output(component_id='start-button', component_property='disabled'),
         Input(component_id='signal', component_property='data'),
     )
     def update_dropdown(in_data):
@@ -930,7 +948,7 @@ if __name__ == "__main__":
         print("dropdown menu options updated")
         # all_plot_sym = ["SPY", "AMZN"]
 
-        return sorted(all_plot_sym), False
+        return sorted(all_plot_sym), False, False
 
     @callback(
         Output(component_id='controls-and-graph', component_property='figure'),