UI components in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a push button in a MATLAB UI.

MATLAB

btn = uicontrol('Style', [1], 'String', 'Click Me');

Drag options to blanks, or click blank then click option'

Atext

Bedit

Cpushbutton

Dslider

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'edit' or 'text' instead of 'pushbutton' for a button.

The 'Style' property set to 'pushbutton' creates a clickable button in MATLAB UI.

2fill in blank

medium

Complete the code to create a slider UI component with a range from 0 to 100.

MATLAB

sld = uicontrol('Style', 'slider', 'Min', 0, 'Max', 100, 'Value', [1]);

Drag options to blanks, or click blank then click option'

A25

B50

C100

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting 'Value' outside the 'Min' and 'Max' range.

The 'Value' property sets the initial position of the slider. 50 is the middle of the range 0 to 100.

3fill in blank

hard

Fix the error in the code to create a text label in a MATLAB UI.

MATLAB

lbl = uicontrol('Style', [1], 'String', 'Hello World');

Drag options to blanks, or click blank then click option'

Apushbutton

Bslider

Cedit

Dtext

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'edit' or 'pushbutton' instead of 'text' for labels.

The 'Style' property must be set to 'text' to create a label that displays static text.

4fill in blank

hard

Fill both blanks to create a checkbox with the label 'Accept Terms'.

MATLAB

chk = uicontrol('Style', [1], 'String', [2]);

Drag options to blanks, or click blank then click option'

Acheckbox

Bpushbutton

C'Accept Terms'

D'Click Me'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pushbutton' style or wrong label text.

Setting 'Style' to 'checkbox' creates a checkbox, and 'String' sets its label.

5fill in blank

hard

Fill all three blanks to create a popup menu with options 'Red', 'Green', and 'Blue'.

MATLAB

popup = uicontrol('Style', [1], 'String', [2], 'Value', [3]);

Drag options to blanks, or click blank then click option'

Apopupmenu

B{'Red', 'Green', 'Blue'}

C1

Dslider

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong style or incorrect format for options.

'popupmenu' style creates a dropdown menu, 'String' sets the options, and 'Value' sets the default selected option index.

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