Picker and DatePicker in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a UIPickerView used for in iOS development?

A UIPickerView lets users select a value from a list by spinning a wheel-like interface. It's like choosing an option from a rotating menu.

beginner

How does UIDatePicker help users in an app?

UIDatePicker lets users pick dates and times easily using a familiar scrolling wheel or calendar style. It simplifies entering date/time information.

intermediate

Which protocol must a class conform to for providing data to a UIPickerView?

The class must conform to <code>UIPickerViewDataSource</code> to provide the number of components and rows, and <code>UIPickerViewDelegate</code> to provide the content and handle selection.

intermediate

What property of UIDatePicker controls whether it shows date, time, or both?

The datePickerMode property controls the display mode. It can be set to .date, .time, or .dateAndTime.

intermediate

How can you respond when a user changes the selected value in a UIPickerView?

Implement the delegate method pickerView(_:didSelectRow:inComponent:). This method is called whenever the user picks a new row.

Which method provides the number of rows in a UIPickerView component?

A pickerView(_:didSelectRow:inComponent:)

B pickerView(_:titleForRow:forComponent:)

C pickerView(_:numberOfRowsInComponent:)

D numberOfComponents(in:)

The method pickerView(_:numberOfRowsInComponent:) tells the picker how many rows to show in each component.

What property of UIDatePicker sets it to show only time?

A mode = .date

B mode = .dateAndTime

C pickerMode = .time

D datePickerMode = .time

Setting datePickerMode to .time makes the UIDatePicker show only the time selection.

Which delegate method is called when a user selects a new row in UIPickerView?

A pickerView(_:didSelectRow:inComponent:)

B pickerView(_:titleForRow:forComponent:)

C pickerView(_:numberOfRowsInComponent:)

D pickerView(_:viewForRow:forComponent:reusing:)

pickerView(_:didSelectRow:inComponent:) is called when the user changes the selection.

How many components does a basic UIPickerView usually have?

A Three

B One

C Two

D Zero

Most simple pickers have one component, like a single spinning wheel.

Which class is used to let users pick dates and times in iOS?

A UIDatePicker

B UIPickerView

C UITableView

D UICollectionView

UIDatePicker is the built-in control for selecting dates and times.

Explain how to set up a UIPickerView to show a list of options and respond when the user picks one.

Think about how you tell the picker what to show and how to react when the user spins the wheel.

Describe how to configure a UIDatePicker to let users pick only a date, and how to get the selected date.

Focus on the mode property and how to listen for changes.