Why MATLAB apps share tools - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a MATLAB app that shares a tool between two buttons.

MATLAB

sharedTool = uicontrol('Style','[1]');

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

Acheckbox

Bpushbutton

Cedit

Dslider

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a control that is not a button, like 'slider' or 'edit'.

The 'pushbutton' style creates a button control, which is commonly used as a tool in MATLAB apps.

2fill in blank

medium

Complete the code to assign the shared tool to two buttons in the app.

MATLAB

button1 = uicontrol('Style', 'pushbutton', 'Callback', @[1]);
button2 = uicontrol('Style', 'pushbutton', 'Callback', @[1]);

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

AtoolCallback

BbuttonCallback

CsharedToolCallback

DappCallback

Attempts:

3 left

💡 Hint

Common Mistakes

Using different callback names for each button.

Both buttons use the same callback function 'sharedToolCallback' to share the tool's behavior.

3fill in blank

hard

Fix the error in the callback function to correctly share the tool's state.

MATLAB

function [1](src, event)
    persistent toolState
    if isempty(toolState)
        toolState = false;
    end
    toolState = ~toolState;
    disp(['Tool is now: ', num2str(toolState)]);
end

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

AsharedToolCallback

BtoolCallback

CbuttonCallback

DappCallback

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching function names causing callback errors.

The function name must match the callback assigned to the buttons, which is 'sharedToolCallback'.

4fill in blank

hard

Fill both blanks to create a shared tool that toggles visibility of two UI elements.

MATLAB

function [1](src, event)
    persistent isVisible
    if isempty(isVisible)
        isVisible = true;
    end
    isVisible = ~isVisible;
    set(uiElement1, 'Visible', [2]);
    set(uiElement2, 'Visible', [2]);
end

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

AtoggleVisibility

Bon

Coff

Dvisible

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect visibility strings or function names.

The function 'toggleVisibility' toggles the visibility state. The visibility is set to 'on' or 'off' based on the state.

5fill in blank

hard

Fill all three blanks to create a shared tool that updates a label text based on a toggle state.

MATLAB

function [1](src, event)
    persistent toggleState
    if isempty(toggleState)
        toggleState = false;
    end
    toggleState = ~toggleState;
    if toggleState
        set(labelHandle, 'String','[2]');
    else
        set(labelHandle, 'String','[3]');
    end
end

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

AupdateLabel

BTool is ON

CTool is OFF

DToggle State

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong strings for label text or mismatched function names.

The function 'updateLabel' updates the label text to 'Tool is ON' or 'Tool is OFF' depending on the toggle state.

Practice

1. Why do MATLAB apps share tools like functions or UI components?

easy

A. To make apps run slower

B. To save time and keep work consistent across apps

C. To increase the size of the app files

D. To confuse users with different interfaces

Solution

1. Step 1: Understand the purpose of shared tools

   Shared tools help reuse code and design elements, reducing repeated work.

2. Step 2: Identify the benefit of consistency

   Using the same tools keeps apps uniform and easier to maintain.

3. Final Answer:

   To save time and keep work consistent across apps -> Option B

4. Quick Check:

   Shared tools = save time + consistency [OK]

Hint: Shared tools save time and keep apps consistent [OK]

Common Mistakes:

• Thinking shared tools slow down apps
• Believing shared tools increase app size
• Assuming shared tools confuse users

2. Which of the following is the correct way to share a function between MATLAB apps?

easy

A. Copy the function code into each app separately

B. Use different function names for each app

C. Rewrite the function inside each app's code

D. Save the function as a separate file and call it from apps

Solution

1. Step 1: Identify proper code sharing method

   Saving a function as a separate file allows multiple apps to call it without duplication.

2. Step 2: Understand why copying or rewriting is bad

   Copying or rewriting causes maintenance problems and inconsistency.

3. Final Answer:

   Save the function as a separate file and call it from apps -> Option D

4. Quick Check:

   Separate file function sharing = correct [OK]

Hint: Use separate function files to share code [OK]

Common Mistakes:

• Copying code instead of sharing
• Rewriting functions multiple times
• Using different names causing confusion

3. Consider two MATLAB apps that share a UI component saved as a function file. If the UI component is updated in the function file, what happens when both apps run next time?

medium

A. Neither app uses the updated component unless copied manually

B. Only the first app uses the updated component

C. Both apps use the updated UI component automatically

D. Both apps crash due to version conflict

Solution

1. Step 1: Understand shared function behavior

   Apps calling the same function file use the latest version when run.

2. Step 2: Recognize automatic update effect

   Updating the shared file means all apps using it get the update without manual changes.

3. Final Answer:

   Both apps use the updated UI component automatically -> Option C

4. Quick Check:

   Shared function update = apps auto-update [OK]

Hint: Shared files update all apps automatically [OK]

Common Mistakes:

• Thinking only one app updates
• Believing manual copying is needed
• Assuming apps crash on update

4. You have two MATLAB apps sharing a data processing function. After updating the function, one app shows errors while the other works fine. What is the likely cause?

medium

A. One app uses an old cached version of the function

B. The function file was deleted accidentally

C. Both apps have different MATLAB versions installed

D. The function was never shared properly

Solution

1. Step 1: Identify caching behavior in MATLAB

   Sometimes MATLAB keeps old versions in memory until refreshed or restarted.

2. Step 2: Explain why one app errors and the other doesn't

   The app with errors likely uses an old cached function version incompatible with updates.

3. Final Answer:

   One app uses an old cached version of the function -> Option A

4. Quick Check:

   Old cache causes errors [OK]

Hint: Clear cache or restart MATLAB to fix shared function errors [OK]

Common Mistakes:

• Assuming function file was deleted
• Blaming MATLAB version mismatch
• Ignoring caching issues

5. You want to create two MATLAB apps that share a complex data visualization tool and a data processing function. How should you organize your files to make maintenance easiest?

hard

A. Put the visualization and processing code in separate function files and call them from both apps

B. Copy the visualization and processing code into each app's main file

C. Write all code inside one app and copy it to the other when needed

D. Use different function names for each app to avoid conflicts

Solution

1. Step 1: Understand modular code organization

   Separating shared tools into function files allows both apps to use the same code easily.

2. Step 2: Recognize maintenance benefits

   Updating one function file updates both apps, reducing errors and effort.

3. Final Answer:

   Put the visualization and processing code in separate function files and call them from both apps -> Option A

4. Quick Check:

   Separate shared files = easier maintenance [OK]

Hint: Use separate shared files for easy updates [OK]

Common Mistakes:

• Copying code into each app causes duplication
• Keeping all code in one app limits reuse
• Using different names causes confusion