In last part, we introduced how to add an axes to plot a graph of sine function. Here we will describe that colors can be chosen in popup menu to change the color of curves.

We firstly, as usual, add a popup menu on the GUI app with the guide tool. The following procedures show the way of implementing a popup menu.

• 1 Click the popup menu widget to add it on our app;

• 2 Double-click on the popupmenu to call the setting interface;

• 3 Modify some settings, e.g. font size, weight, color;

• 4 double-click on the String to call the value interface, and you can add some color names in the list;

• 5 Modify the Tag to locate the callback function of the popup menu in m file;

• 6 Obtain the chosen value when you choose some color, and two lines should be added to do it.

 1 2 3  list = get( hObject, 'String' ); % Get the listof all strings. val = get( hObject, 'Value' ); % Get the index of the chosen string. color = list{ val }; % Get the chosen string. 

### 2 Run the app

• 1 Run the m file;
• 2 Choose a color to plot the sine function.