Creating a Radio Button Group in MATLAB App Designer

MATLAB App Designer is a powerful tool that allows users to create professional apps without having to be an expert in programming. It provides a rich set of components and a drag-and-drop environment that makes it easy to design and build custom apps. One common component used in many apps is the radio button group, which allows users to select one option from a set of choices. In this article, we will explore how to create a radio button group in MATLAB App Designer, discuss its properties and callbacks, and demonstrate practical applications with examples.

What is a Radio Button Group?

A radio button group is a UI component that allows users to choose one option from a group of mutually exclusive options. In MATLAB App Designer, radio buttons are typically grouped together in a ButtonGroup object, which ensures that only one button can be selected at a time. This is particularly useful in cases where you want to restrict the user to a single choice, such as selecting a preferred payment method, choosing a type of graph, or specifying an operating mode for a device.

Why Use Radio Button Groups?

Radio button groups are an excellent choice when you need to enforce single selection. They provide a clear visual indication of which option is selected and prevent users from making multiple choices that might conflict. This is different from checkboxes, which allow for multiple selections. For example, if you are developing an app that configures a device, you might use a radio button group to select between different modes of operation, such as "Manual," "Automatic," or "Test."

Creating a Radio Button Group in MATLAB App Designer

To create a radio button group in MATLAB App Designer, follow these steps:

1. Open MATLAB App Designer: Start MATLAB and open App Designer by clicking on the "App Designer" button from the MATLAB Toolstrip.

2. Drag and Drop a Button Group Component: From the "Component Library" panel, drag a ButtonGroup onto the app canvas. This will create a container for your radio buttons.

3. Add Radio Buttons: With the ButtonGroup selected, click on the "Component Library" again and drag a RadioButton into the ButtonGroup. Repeat this step to add as many radio buttons as needed. Each radio button represents an option within the group.

4. Set Properties: With each radio button selected, you can set properties such as the Text (which appears next to the button) and the Value (which is true when the button is selected). You can also set properties for the entire button group, such as the Title that appears above the group.

5. Add Callbacks: Callbacks are functions that execute in response to user interactions. For a radio button group, you might want to add a callback that responds when the selection changes. To do this, select the ButtonGroup, go to the "Component Browser," right-click on the SelectionChangedFcn property, and select "Add Callback."

Example: Implementing a Simple Radio Button Group

Let's walk through a simple example where we create a radio button group that allows the user to select their preferred color for a plot.

Step-by-Step Guide:

1. Start a New App: Open App Designer and create a new blank app.

2. Add a Button Group: Drag a ButtonGroup from the "Component Library" to the canvas and set its Title property to "Select Color."

3. Add Radio Buttons: Within the ButtonGroup, add three RadioButton components. Set their Text properties to "Red," "Green," and "Blue."

4. Set a Default Selection: Set the Value property of the "Red" radio button to true to make it the default selected button.

5. Add an Axes for Plotting: Drag an Axes component from the "Component Library" onto the canvas. This will be where the plot is displayed.

6. Create a Plotting Callback: Right-click on the SelectionChangedFcn of the ButtonGroup and select "Add Callback." This will open the code view and create a function template. Within this function, add code to change the plot color based on the selected radio button:

   matlab
   function ButtonGroup_SelectionChanged(app, event)
       selectedButton = app.ButtonGroup.SelectedObject;
       color = 'r'; % Default color is red
       if strcmp(selectedButton.Text, 'Green')
           color = 'g';
       elseif strcmp(selectedButton.Text, 'Blue')
           color = 'b';
       end
       plot(app.UIAxes, rand(5), color); % Plot with the selected color
   end
   

7. Run the App: Click the "Run" button in the toolbar to test the app. Changing the selection in the radio button group should update the plot color accordingly.

Understanding Properties and Callbacks

The example above demonstrates some fundamental concepts about properties and callbacks in MATLAB App Designer:

• Properties: These are attributes of the UI components, such as the Text property of a radio button or the Title of a button group. Properties control the appearance and behavior of components.

• Callbacks: These are functions that execute in response to user actions, such as clicking a button or changing a selection. In App Designer, callbacks are defined as methods in the app class, allowing them to access and modify other components in the app.

Advanced Customization and Features

Once you are comfortable with the basics, you can explore more advanced features and customizations:

• Dynamic Button Creation: You can create radio buttons dynamically at runtime using MATLAB code. This is useful if the number of options is not known at design time.

• Customizing Appearance: MATLAB provides various options to customize the appearance of radio buttons and groups, such as changing fonts, colors, and sizes.

• Handling Different Data Types: Radio buttons can be used to select different data types, such as strings, numbers, or custom objects. You can handle these types in callbacks to perform different actions based on the selection.

• Enabling and Disabling Components: You can enable or disable individual radio buttons or entire button groups based on the app state or user input.

Practical Applications

Radio button groups are versatile and can be used in various applications:

• Survey Forms: Use radio buttons to capture user preferences or opinions, such as satisfaction ratings or demographic information.

• Configuration Panels: Radio buttons are ideal for settings panels where the user needs to choose among different modes, such as color schemes, data formats, or system behaviors.

• Interactive Plots: As shown in the example, radio buttons can be used to modify plots dynamically, allowing users to interact with data visualizations.

Conclusion

Creating a radio button group in MATLAB App Designer is a straightforward process that adds significant interactivity and usability to your apps. By understanding the properties and callbacks associated with radio buttons, you can create sophisticated user interfaces that respond to user input and provide dynamic feedback. Whether you are building simple apps for data analysis or complex tools for engineering applications, mastering radio button groups will enhance your ability to create intuitive and functional user interfaces in MATLAB.

By following the steps outlined in this article, you should be able to create and customize radio button groups in your own MATLAB apps, making them more interactive and user-friendly.