Keyboard management in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to dismiss the keyboard when the user taps outside the text field.

iOS Swift

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
  self.view.[1]()
}

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

AendEditing(true)

BbecomeFirstResponder()

CresignFirstResponder()

DreloadInputViews()

Attempts:

3 left

💡 Hint

Common Mistakes

Using becomeFirstResponder() which actually shows the keyboard.

Using resignFirstResponder() on the view, which is not correct.

Calling endEditing(true) on the view dismisses the keyboard by ending editing on the current first responder.

2fill in blank

medium

Complete the code to move the view up when the keyboard appears.

iOS Swift

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)

@objc func keyboardWillShow(notification: NSNotification) {
  if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
    self.view.frame.origin.y = [1]
  }
}

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

A-keyboardSize.height

BkeyboardSize.height

C0

DkeyboardSize.width

Attempts:

3 left

💡 Hint

Common Mistakes

Using positive keyboard height which moves the view down.

Using keyboard width instead of height.

To move the view up, subtract the keyboard height from the view's origin y position.

3fill in blank

hard

Fix the error in the code to reset the view position when the keyboard hides.

iOS Swift

@objc func keyboardWillHide(notification: NSNotification) {
  self.view.frame.origin.y = [1]
}

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

Aself.view.frame.origin.y

Bself.view.frame.height

C-self.view.frame.height

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using the view's height which moves the view off screen.

Using negative height which moves the view further up.

Resetting the view's origin y to 0 moves it back to its original position.

4fill in blank

hard

Fill both blanks to add observers for keyboard show and hide notifications.

iOS Swift

NotificationCenter.default.addObserver(self, selector: #selector([1]), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector([2]), name: UIResponder.keyboardWillHideNotification, object: nil)

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

AkeyboardWillShow

BkeyboardDidShow

CkeyboardWillHide

DkeyboardDidHide

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Did' notifications which happen after the keyboard animation.

Mixing show and hide selectors incorrectly.

Use keyboardWillShow and keyboardWillHide selectors to respond to keyboard appearance and disappearance.

5fill in blank

hard

Fill all three blanks to properly remove keyboard observers in deinit.

iOS Swift

deinit {
  NotificationCenter.default.[1](self, name: UIResponder.keyboardWillShowNotification, object: nil)
  NotificationCenter.default.[2](self, name: UIResponder.keyboardWillHideNotification, object: nil)
  NotificationCenter.default.[3](self)
}

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

AremoveObserver

BaddObserver

Cpost

DremoveAllObservers

Attempts:

3 left

💡 Hint

Common Mistakes

Using addObserver instead of removeObserver.

Trying to call a non-existent removeAllObservers method.

Use removeObserver to unregister from notifications to avoid memory leaks.

Practice

1. What is the main purpose of managing the keyboard in an iOS app?

easy

A. To disable typing in text fields

B. To keep input fields visible when the keyboard appears

C. To change the keyboard color

D. To automatically save user input

Solution

1. Step 1: Understand keyboard impact on UI

   The keyboard can cover input fields, making them hard to see or use.

2. Step 2: Purpose of keyboard management

   Managing the keyboard ensures input fields stay visible and accessible when typing.

3. Final Answer:

   To keep input fields visible when the keyboard appears -> Option B

4. Quick Check:

   Keyboard management = keep inputs visible [OK]

Hint: Keyboard management keeps inputs visible when typing [OK]

Common Mistakes:

• Thinking keyboard management changes keyboard color
• Believing it disables typing
• Assuming it auto-saves input

2. Which Swift method is used to dismiss the keyboard when tapping outside a UITextField?

easy

A. textField.resignFirstResponder()

B. textField.becomeFirstResponder()

C. textField.showKeyboard()

D. textField.hideKeyboard()

Solution

1. Step 1: Identify method to dismiss keyboard

   Calling resignFirstResponder() on a UITextField tells it to stop being active, hiding the keyboard.

2. Step 2: Check other options

   becomeFirstResponder() shows keyboard; showKeyboard() and hideKeyboard() do not exist in UIKit.

3. Final Answer:

   textField.resignFirstResponder() -> Option A

4. Quick Check:

   Dismiss keyboard = resignFirstResponder() [OK]

Hint: Use resignFirstResponder() to hide keyboard [OK]

Common Mistakes:

• Using becomeFirstResponder() which shows keyboard
• Trying non-existent methods like hideKeyboard()
• Not calling any method to dismiss keyboard

3. Given this Swift code snippet, what happens when the keyboard appears?

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)

@objc func keyboardWillShow(notification: NSNotification) {
  if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
    scrollView.contentInset.bottom = keyboardSize.height
  }
}

medium

A. Nothing happens when keyboard appears

B. The keyboard is hidden automatically

C. The scroll view scrolls to top

D. The scroll view's bottom inset increases to avoid keyboard overlap

Solution

1. Step 1: Understand notification observer

   The code listens for keyboard showing and calls keyboardWillShow function.

2. Step 2: Adjust scroll view inset

   Inside keyboardWillShow, it sets scrollView.contentInset.bottom to keyboard height, pushing content up.

3. Final Answer:

   The scroll view's bottom inset increases to avoid keyboard overlap -> Option D

4. Quick Check:

   Keyboard show adjusts scroll inset [OK]

Hint: Keyboard show notification adjusts scroll inset bottom [OK]

Common Mistakes:

• Thinking keyboard hides automatically
• Assuming scroll view scrolls to top
• Ignoring contentInset adjustment

4. What is wrong with this Swift code for dismissing the keyboard?

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
  view.endEditing(true)
}

medium

A. endEditing(true) does not dismiss keyboard

B. TouchesBegan is not called on UIViewController

C. It should call super.touchesBegan to propagate touch events

D. The method signature is incorrect

Solution

1. Step 1: Check method override

   Overriding touchesBegan requires calling super.touchesBegan to allow normal touch handling.

2. Step 2: Identify missing call

   The code misses super.touchesBegan, which can cause touch events to stop propagating.

3. Final Answer:

   It should call super.touchesBegan to propagate touch events -> Option C

4. Quick Check:

   Override touchesBegan must call super [OK]

Hint: Always call super in overridden touchesBegan [OK]

Common Mistakes:

• Not calling super.touchesBegan
• Thinking endEditing(true) doesn't dismiss keyboard
• Using wrong method signature

5. You want to move the view up when the keyboard appears and move it back down when it hides. Which approach correctly handles this in Swift?

hard

A. Listen to keyboardWillShow and keyboardWillHide notifications, adjust view frame accordingly

B. Only listen to keyboardDidShow notification and adjust view frame

C. Use a timer to check keyboard height every second and move view

D. Change the keyboard type to avoid covering the view

Solution

1. Step 1: Understand keyboard notifications

   keyboardWillShow and keyboardWillHide notify before keyboard appears/disappears, allowing smooth UI changes.

2. Step 2: Adjust view frame on both notifications

   Adjusting view frame up on show and back down on hide keeps UI consistent and responsive.

3. Step 3: Evaluate other options

   Listening only to keyboardDidShow is late; timer wastes resources; changing keyboard type doesn't solve overlap.

4. Final Answer:

   Listen to keyboardWillShow and keyboardWillHide notifications, adjust view frame accordingly -> Option A

5. Quick Check:

   Use willShow and willHide notifications for UI moves [OK]

Hint: Use willShow and willHide notifications to move views [OK]

Common Mistakes:

• Using only keyboardDidShow notification
• Polling keyboard height with timer
• Trying to change keyboard type to fix layout