Manage UI Components

When you add a UI component to your app, App Designer assigns a default name to the component. Use that name (including the app prefix) to refer to the component in your code. You can change the name of a component by double-clicking the name in the Component Browser and typing a new name. App Designer automatically updates all references to that component when you change its name.

To use the name of a component in your code, you can save some time by copying the name from the Component Browser. Place your cursor in an editable area of the code where you want to add the component name. Then, from the Component Browser, right-click the component name and select Insert at Cursor. Alternatively, you can drag the component name from the list into your code.

To delete a component, select its name in the Component Browser and press the Delete key.

Manage Callbacks

To make a component respond to user interactions, add a callback. Right-click the component in the Component Browser and select Callbacks > Add (callback property) callback.

If you delete a component from your app, App Designer deletes the associated callback only if the callback has not been edited and is not shared with other components.

To delete a callback manually, select the callback name in the Callbacks tab of the Code Browser and press the Delete key.

For more information about callbacks, see Callbacks in App Designer.

Share Data Within Your App

To store data, and share it among different callbacks, create a property. For example, if want your app to read a data file and allow different callbacks in your app to access that data, store the data in a property when you load the file.

To create a property, expand the Property drop-down in the Editor tab, and select Private Property or Public Property. App Designer creates a template property definition and places your cursor next to that definition. Change the name of the property as desired.

properties (Access = public)
        X % Average cost
end

To reference the property in your code, use the syntax app.PropertyName. For example, app.X references the property named X.

For more information about creating and using properties, see Share Data Within App Designer Apps.

Single-Source Code that Runs in Multiple Places

If you want to execute a block of code in multiple parts of your app, create a helper function. For example, you might create a helper function to update a plot after the user changes a number in an edit field or selects an item in a drop-down list. Creating a helper function allows you to single-source the common commands and avoid having to maintain redundant sets of code.

To add a helper function, expand the Function drop-down in the Editor tab, and select Private Function or Public Function. App Designer creates a template function and places your cursor in the body of that function.

To delete a helper function, select the function name in the Functions tab of the Code Browser and press the Delete key.

For more information about writing helper functions, see Reuse Code Using Helper Functions.

Create Input Arguments

To add input arguments to your app, click App Input Arguments in the Editor tab. Input arguments are commonly used for creating apps that have multiple windows. For more information, see Startup Tasks and Input Arguments in App Designer.

Add Help Text for Your App

Add an app summary and description to provide information about your app to users. To add help text or to edit existing help text, click App Help Text . Use the App Help Text dialog box to specify a short summary of the app and a more detailed explanation of what the app does and how to use it. App Designer adds this help text as a comment under the app definition statement.

To display app help text in the MATLAB Command Window, call the help function and specify the app name. In addition, app help text appears at the top of the documentation page for your app. You can view the documentation page for your app by calling the doc function and specifying the app name.

Limit Your App to Only One Running Instance at a Time

When you create an app in App Designer you have the option to select between two run behaviors for the app:

To change the run behavior of your app, select the app node from the Component Browser. Then, from the Code Options section of the App tab, select or clear Single Running Instance.

When Single Running Instance is selected and you run the app multiple times, MATLAB reuses the existing instance and brings it to the front rather than creating a new one. When this option is cleared, MATLAB creates a new app instance each time you run it and continues to run the existing instances. These run behaviors apply to apps that you run from the Apps tab on the MATLAB Toolstrip or from the Command Window.

When you run apps from App Designer their behavior doesn't change whether this option is selected or cleared. App Designer always closes the existing app instance before creating a new one.

Change Color Settings

To change the color settings for editable sections of code and to customize syntax highlighting, select MATLAB > Colors and adjust the desktop tool colors and the MATLAB syntax highlighting colors. These settings affect both the App Designer Code View editor and the MATLAB Editor. For more information, see Change Desktop Colors.

To change the background color of uneditable sections of code, select MATLAB > App Designer and adjust the read-only background color. This setting can be changed only if the Use system colors option in MATLAB > Color Preferences is unchecked.

Change Tab Preferences

To specify the size of tabs and indents in the Code View editor, select MATLAB > Editor/Debugger > Tab. From here, you can specify the size of tabs and indents, as well as details about how tabs behave. These preferences affect both the App Designer Code View editor and the MATLAB Editor. For more information, see Editor/Debugger Tab Preferences.