UI components in MATLAB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a UI component in MATLAB?

A UI component in MATLAB is a graphical element like a button, slider, or text box that users interact with in a graphical user interface (GUI).

beginner

How do you create a push button in MATLAB?

You create a push button using the uicontrol function with the 'Style' property set to 'pushbutton'. For example:
btn = uicontrol('Style', 'pushbutton', 'String', 'Click me');

beginner

What property controls the text displayed on a UI component like a button or label?

The 'String' property controls the text shown on UI components such as buttons or labels.

intermediate

How can you respond to a button click in MATLAB UI?

You assign a callback function to the button's 'Callback' property. This function runs when the button is clicked.

beginner

Name three common UI components in MATLAB.

Three common UI components are:

• Push button (uicontrol with 'Style' set to 'pushbutton')
• Slider (uicontrol with 'Style' set to 'slider')
• Text label (uicontrol with 'Style' set to 'text')

Which MATLAB function is commonly used to create UI components?

A input

B plot

C disp

D uicontrol

The uicontrol function creates UI components like buttons and sliders.

What property sets the text shown on a MATLAB button?

A Text

B Label

C String

D Title

The 'String' property controls the text displayed on UI components.

How do you make a MATLAB button respond when clicked?

A Set the 'Callback' property

B Set the 'Action' property

C Set the 'Click' property

D Set the 'Event' property

The 'Callback' property defines the function to run on button click.

Which style value creates a slider in MATLAB UI?

A 'pushbutton'

B 'slider'

C 'edit'

D 'text'

Using 'slider' as the 'Style' creates a slider component.

What does the 'uicontrol' function NOT create?

A Plot graph

B Slider

C Button

D Text label

uicontrol creates UI elements, not plots or graphs.

Explain how to create a simple button in MATLAB and make it respond to clicks.

Think about the properties you set when making a button and how to run code when clicked.

List and describe three common UI components you can create in MATLAB.

Consider components users interact with to input or see information.

Practice

1. Which MATLAB function is used to create a new interactive window for UI components?

easy

A. window

B. uifigure

C. uiwindow

D. figure

Solution

1. Step 1: Understand the purpose of UI windows

   MATLAB uses a special function to create windows that support interactive UI components like buttons and sliders.

2. Step 2: Identify the correct function for UI windows

   The function uifigure creates a window designed for UI components, unlike figure which is for plots.

3. Final Answer:

   uifigure -> Option B

4. Quick Check:

   UI window = uifigure [OK]

Hint: Use uifigure for UI windows, not figure [OK]

Common Mistakes:

• Confusing uifigure with figure
• Using non-existent functions like uiwindow
• Assuming window creates UI windows

2. Which of the following is the correct syntax to add a button to a UI figure named fig?

easy

A. btn = uibutton();

B. btn = button(fig);

C. btn = addbutton(fig);

D. btn = uibutton(fig);

Solution

1. Step 1: Recall the function to create buttons in UI figures

   MATLAB uses uibutton to create buttons inside a UI figure.

2. Step 2: Check the syntax for specifying the parent UI figure

   The parent figure must be passed as an argument to uibutton, so uibutton(fig); is correct.

3. Final Answer:

   btn = uibutton(fig); -> Option D

4. Quick Check:

   Button creation = uibutton(fig) [OK]

Hint: Always pass the figure handle to uibutton [OK]

Common Mistakes:

• Using button() instead of uibutton()
• Not passing the figure as argument
• Using non-existent addbutton() function

3. What will be the output when running this code?

fig = uifigure();
btn = uibutton(fig, 'Text', 'Click Me');
disp(btn.Text);

medium

A. Click Me

B. uibutton

C. btn

D. Error: Text property not found

Solution

1. Step 1: Understand button creation with text

   The button is created with the text property set to 'Click Me'.

2. Step 2: Display the button's Text property

   Using disp(btn.Text) prints the string assigned to the Text property.

3. Final Answer:

   Click Me -> Option A

4. Quick Check:

   Button text = 'Click Me' [OK]

Hint: disp(btn.Text) shows button label text [OK]

Common Mistakes:

• Expecting the variable name instead of text
• Thinking btn.Text is invalid property
• Confusing output with object type

4. Identify the error in this code snippet:

fig = uifigure();
btn = uibutton(fig);
btn.Callback = @(src,event) disp('Button clicked');

medium

A. Property name should be ButtonPushedFcn, not Callback

B. uifigure() cannot have buttons

C. Anonymous functions cannot be used as callbacks

D. disp cannot be used inside callbacks

Solution

1. Step 1: Check the correct callback property for uibutton

   In MATLAB UI buttons, the callback property is named ButtonPushedFcn, not Callback.

2. Step 2: Understand the effect of wrong property name

   Assigning to Callback does nothing; the button won't respond to clicks.

3. Final Answer:

   Property name should be ButtonPushedFcn, not Callback -> Option A

4. Quick Check:

   Button callback = ButtonPushedFcn [OK]

Hint: Use ButtonPushedFcn for button callbacks [OK]

Common Mistakes:

• Using Callback instead of ButtonPushedFcn
• Thinking anonymous functions are invalid
• Believing buttons can't be added to uifigure

5. You want to create a UI with a slider that updates a label text showing the slider value in real-time. Which approach correctly sets this up?

hard

A. Create slider and label, then use a loop to constantly check slider.Value and update label.Text

B. Create slider and label, then set label's ValueChangedFcn to update slider.Value inside the callback

C. Create slider and label, then set slider's ValueChangedFcn to update label.Text inside the callback

D. Create slider and label, then set slider's ButtonPushedFcn to update label.Text

Solution

1. Step 1: Understand slider and label interaction

   The slider's ValueChangedFcn triggers when the slider moves, perfect for updating the label.

2. Step 2: Set callback to update label text

   Inside the slider's callback function, update the label's Text property to show the current slider value.

3. Final Answer:

   Create slider and label, then set slider's ValueChangedFcn to update label.Text inside the callback -> Option C

4. Quick Check:

   Slider update uses ValueChangedFcn callback [OK]

Hint: Use slider's ValueChangedFcn to update label text [OK]

Common Mistakes:

• Using label's ValueChangedFcn instead of slider's
• Using ButtonPushedFcn on slider (not valid)
• Using loops instead of callbacks