Using Radio Buttons in MATLAB App Designer

MATLAB App Designer is a powerful tool for creating professional apps with a graphical user interface (GUI) without requiring extensive knowledge of programming. One of the essential components in creating interactive user interfaces is the radio button. In this article, we will explore the use of radio buttons in MATLAB App Designer, including how to create them, customize their appearance and behavior, and handle their callback functions.

What is a Radio Button?

A radio button is a GUI component that allows users to select one option from a predefined set of options. Unlike checkboxes, where multiple selections are possible, radio buttons restrict the user to a single choice within a group. They are commonly used in forms and settings menus where a user must choose one configuration or option.

Creating Radio Buttons in MATLAB App Designer

To begin working with radio buttons in MATLAB App Designer, follow these steps:

1. Open App Designer: Start MATLAB and open App Designer by clicking on "App Designer" in the "HOME" tab.

2. Add a Radio Button Group: From the "Component Library" on the left side, drag a "Radio Button Group" component onto your app’s design canvas. The "Radio Button Group" serves as a container for individual radio buttons.

3. Add Radio Buttons: Once the group is placed, you can add individual radio buttons to this group. Simply drag the "Radio Button" component into the "Radio Button Group" container.

4. Customize Radio Buttons: You can customize the radio buttons by selecting them and modifying properties such as the label text, position, and size. This is done in the "Component Browser" and "Inspector" panes.

Customizing Appearance and Behavior

MATLAB App Designer allows you to modify various aspects of radio buttons to match the desired appearance and functionality of your app.

• Labels: The label of each radio button can be set directly in the "Component Browser." This text represents the option that the radio button corresponds to.

• Default Selection: You can set a default selection by specifying which radio button is selected when the app starts. This is crucial for ensuring that your app has a predefined state.

• Positioning: Use the "Inspector" pane to adjust the position and size of radio buttons and their containing group. Precise positioning helps in creating a clean and user-friendly interface.

• Grouping: The "Radio Button Group" ensures that all contained radio buttons are mutually exclusive, meaning only one can be selected at a time. If you need multiple groups of radio buttons, simply add more "Radio Button Group" components to your app.

Handling Callbacks

One of the key aspects of using radio buttons is handling the user’s selection. This is done through callbacks—functions that are triggered when the user interacts with the radio button.

• Creating a Callback: In the "Component Browser," right-click on the "Radio Button Group" and select "Callback > Add ValueChangedFcn callback." This creates a function in the code where you can define what happens when a radio button’s value changes.

• Accessing the Selected Button: Inside the callback function, you can determine which radio button was selected by accessing the "Value" property of the "Radio Button Group." This property contains the label of the currently selected radio button.

Example:

matlab
function RadioButtonGroupSelectionChanged(app, event)
    selectedButton = app.RadioButtonGroup.SelectedObject;
    selectedLabel = selectedButton.Text;
    % Implement your logic based on the selected option
end

In this example, the selectedLabel variable will contain the label of the selected radio button, and you can implement further logic based on this selection.

Practical Examples

Example 1: Selecting a Plot Type

Consider an app that allows the user to choose between different types of plots (e.g., line plot, bar plot, scatter plot). A radio button group can be used to let the user select the plot type.

1. Radio Button Labels: "Line Plot", "Bar Plot", "Scatter Plot".
2. Callback Function: The callback function will generate the appropriate plot based on the user's selection.

matlab
function PlotTypeSelectionChanged(app, event)
    selectedButton = app.PlotTypeGroup.SelectedObject;
    selectedLabel = selectedButton.Text;

    switch selectedLabel
        case 'Line Plot'
            plot(app.UIAxes, app.XData, app.YData, '-');
        case 'Bar Plot'
            bar(app.UIAxes, app.XData, app.YData);
        case 'Scatter Plot'
            scatter(app.UIAxes, app.XData, app.YData);
    end
end

Example 2: Configuring App Settings

In another scenario, you might have an app where the user needs to select a specific configuration mode (e.g., "Basic", "Advanced"). Each mode might enable or disable certain features in the app.

1. Radio Button Labels: "Basic", "Advanced".
2. Callback Function: The callback function adjusts the visibility or availability of certain UI components based on the selected mode.

matlab
function ModeSelectionChanged(app, event)
    selectedButton = app.ModeGroup.SelectedObject;
    selectedLabel = selectedButton.Text;

    switch selectedLabel
        case 'Basic'
            app.AdvancedSettingsPanel.Visible = 'off';
        case 'Advanced'
            app.AdvancedSettingsPanel.Visible = 'on';
    end
end

Best Practices

• Use Descriptive Labels: Ensure that the labels of your radio buttons are clear and descriptive. This makes it easier for users to understand what each option represents.

• Logical Grouping: Place radio buttons in groups that make logical sense. For example, if the options are mutually exclusive and belong to the same category, they should be grouped together.

• Handle Default States: Always set a default selection that makes sense for the context of your app. This provides a good starting point for users and avoids confusion.

• Test Callbacks Thoroughly: Since radio buttons often trigger important changes in the app, thoroughly test the callback functions to ensure that all possible selections are handled correctly.

Conclusion

Radio buttons are a simple yet powerful tool in MATLAB App Designer, enabling users to make selections in a clear and intuitive manner. By following the guidelines and examples provided in this article, you can effectively incorporate radio buttons into your MATLAB apps, enhancing their functionality and user experience.

Key Takeaways:

• Radio buttons allow single selections within a group.
• MATLAB App Designer provides easy tools to add and customize radio buttons.
• Proper use of callbacks is essential for handling user input.
• Ensure radio buttons are logically grouped and clearly labeled.

Incorporating radio buttons into your app not only makes it more interactive but also improves the overall user experience by providing clear, user-friendly options.