Creating a Multi-Window Application in MATLAB: A Comprehensive Guide

Introduction
MATLAB is a powerful environment for numerical computation, visualization, and programming. While it's widely known for its use in data analysis and scientific research, MATLAB also provides tools for creating interactive applications. This guide will walk you through the process of designing a multi-window application in MATLAB, highlighting key concepts, practical examples, and best practices.

1. Understanding Multi-Window Applications
Multi-window applications are software applications that can display multiple windows or forms simultaneously. This feature is particularly useful for applications that need to show various types of information at once, such as dashboards, complex data visualizations, or user interfaces that require separate components.

2. MATLAB App Designer Overview
MATLAB's App Designer is a powerful tool for creating interactive applications with a modern, user-friendly interface. It provides a drag-and-drop environment for designing user interfaces and supports the development of complex, multi-window applications. App Designer allows users to create and manage multiple windows or tabs within a single application.

3. Setting Up Your Environment
Before diving into creating a multi-window application, ensure that your MATLAB environment is properly set up:

• MATLAB Version: Ensure you have MATLAB R2016a or later, as App Designer was introduced in this version.
• Toolboxes: Verify that you have the required toolboxes installed. For multi-window applications, you might need the App Designer or GUI Layout Toolbox.

4. Creating a New App in App Designer
To start building your multi-window application:

• Open MATLAB and navigate to the App Designer by typing appdesigner in the command window.
• Click on New App to start a new project. This will open a blank app canvas where you can design your user interface.

5. Designing the Main Window
The main window is the primary interface of your application. Design it by dragging and dropping components from the Component Library. Common components include:

• Buttons: For user interactions.
• Tables: To display data.
• Axes: For plotting graphs.

6. Adding Additional Windows
MATLAB allows you to create additional windows by using separate app files or creating tabs within the main window. Here’s how to manage both approaches:

• Separate App Files:

  • Create a new app file for each additional window by clicking on New App in App Designer.
  • Save each app file with a unique name.

• Tabs within the Main Window:

  • Use the Tab Group component from the Component Library.
  • Drag and drop Tab components to create multiple tabs.

7. Managing Multiple Windows
To manage multiple windows, you'll need to write code to handle interactions between them. This involves:

• Creating Callback Functions: Define what should happen when a user interacts with different components. For example, clicking a button might open a new window or update data in another window.
• Using Global Variables: Share data between windows by using global variables or MATLAB’s guidata function to store and retrieve application data.

8. Implementing Window Switching
Switching between windows can be handled programmatically. You can use functions to:

• Open a New Window: Use the uiopen function or similar commands to open new app windows.
• Close a Window: Use the close function to close the current window.

9. Example: Multi-Window Application
Here’s a simple example of a multi-window application in MATLAB:

Main Window Code:

matlab
classdef MainWindow < matlab.apps.AppBase
    % Properties
    properties (Access = public)
        UIFigure  % Main figure window
        OpenButton  % Button to open a new window
    end

    % Methods
    methods (Access = private)
        function OpenButtonPushed(app, event)
            % Create a new instance of AdditionalWindow
            aw = AdditionalWindow();
            aw.UIFigure.Visible = 'on'; % Show the new window
        end
    end
    
    % Initialization code
    methods (Access = public)
        function app = MainWindow
            % Create UIFigure and components
            app.UIFigure = uifigure('Name', 'Main Window');
            app.OpenButton = uibutton(app.UIFigure, 'push', 'Text', 'Open New Window', 'ButtonPushedFcn', @(src, event) app.OpenButtonPushed());
        end
    end
end

Additional Window Code:

matlab
classdef AdditionalWindow < matlab.apps.AppBase
    % Properties
    properties (Access = public)
        UIFigure  % Additional figure window
        CloseButton  % Button to close the window
    end

    % Methods
    methods (Access = private)
        function CloseButtonPushed(app, event)
            % Close the additional window
            close(app.UIFigure);
        end
    end
    
    % Initialization code
    methods (Access = public)
        function app = AdditionalWindow
            % Create UIFigure and components
            app.UIFigure = uifigure('Name', 'Additional Window');
            app.CloseButton = uibutton(app.UIFigure, 'push', 'Text', 'Close Window', 'ButtonPushedFcn', @(src, event) app.CloseButtonPushed());
        end
    end
end

10. Testing and Debugging
Test your multi-window application thoroughly to ensure all interactions and data sharing work as expected. Use MATLAB’s debugging tools to identify and fix any issues.

11. Conclusion
Creating a multi-window application in MATLAB involves designing user interfaces with App Designer, managing multiple windows or tabs, and implementing code to handle interactions between windows. With these tools and techniques, you can build sophisticated applications that enhance user experience and functionality.

12. References

• MATLAB Documentation: App Designer
• MATLAB Central: Community Contributions and Examples