Customize your app's user interface with views and controls in UIKit.
This sample guides you through several types of customizations that you can make in your iOS app. The sample uses a split view controller architecture for navigating UIKit views and controls. The primary view controller (MasterViewController
) shows the available views and controls. Selecting one shows the secondary view controller associated with it.
The name of each secondary view controller reflects its target item. For example, the AlertControllerViewController
class shows how to use a UIAlertController
object. The only exceptions to this rule are UISearchBar
and UIToolbar
; the sample demonstrates these APIs in multiple view controllers to explain how their controls function and how to customize them. To demonstrate how to manage the complexity of your storyboards, the app hosts all view controllers in a separate storyboard and loaded when needed.
This sample demonstrates the following views and controls (several of which are referenced in the sections below):
UIActivityIndicatorView
UIAlertController
UIButton
UIDatePicker
UIPickerView
UIColorPickerViewController
UIFontPickerViewController
UIImagePickerViewController
UIImageView
UIPageControl
UIProgressView
UISearchBar
UISegmentedControl
UISlider
UIStackView
UIStepper
UISwitch
UITextField
UITextView
UIToolbar
WKWebView
VoiceOver and other system accessibility technologies use the information provided by your views and controls to help all users navigate your content. UIKit views include default accessibility support, but you can improve the user experience by providing custom accessibility information.
In this UIKitCatalog sample, several view controllers configure the accessibilityType
and accessibilityLabel
properties of their associated view. Picker view columns don't have labels, so the picker view asks its delegate for the corresponding accessibility information:
func pickerView(_ pickerView: UIPickerView, accessibilityLabelForComponent component: Int) -> String? {
switch ColorComponent(rawValue: component)! {
case .red:
return NSLocalizedString("Red color component value", comment: "")
case .green:
return NSLocalizedString("Green color component value", comment: "")
case .blue:
return NSLocalizedString("Blue color component value", comment: "")
}
}
AlertControllerViewController
demonstrates several techniques for displaying modal alerts and action sheets from your interface. The configuration process is similar for all alerts:
- Determine the message you want to display in the alert.
- Create and configure a
UIAlertController
object. - Add handlers for actions that the user may take.
- Present the alert controller.
The showSimpleAlert
function uses the NSLocalizedString
function to retrieve the alert messages in the user’s preferred language. The showSimpleAlert
function uses those strings to create and configure the UIAlertController
object. Although the button in the alert has the title OK, the sample uses a cancel action to ensure that the alert controller applies the proper styling to the button:
func showSimpleAlert() {
let title = NSLocalizedString("A Short Title is Best", comment: "")
let message = NSLocalizedString("A message should be a short, complete sentence.", comment: "")
let cancelButtonTitle = NSLocalizedString("OK", comment: "")
let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
// Create the action.
let cancelAction = UIAlertAction(title: cancelButtonTitle, style: .cancel) { _ in
print("The simple alert's cancel action occurred.")
}
// Add the action.
alertController.addAction(cancelAction)
present(alertController, animated: true, completion: nil)
}
This sample demonstrates different ways to display a UISlider
, a control used to select a single value from a continuous range of values. You customize the appearance of a slider by assigning stretchable images for left-side tracking, right-side tracking, and the thumb. In this example, the track image is stretchable and is one pixel wide. Make the track images wider to provide rounded corners, but be sure to set these images' capInsets
property to allow for the corners.
The configureCustomSlider
function sets up a custom slider:
func configureCustomSlider() {
let leftTrackImage = UIImage(named: "slider_blue_track")
customSlider.setMinimumTrackImage(leftTrackImage, for: .normal)
let rightTrackImage = UIImage(named: "slider_green_track")
customSlider.setMaximumTrackImage(rightTrackImage, for: .normal)
// Set the sliding thumb image (normal and highlighted).
let thumbImageConfig = UIImage.SymbolConfiguration(scale: .large)
let thumbImage = UIImage(systemName: "circle.fill", withConfiguration: thumbImageConfig)
customSlider.setThumbImage(thumbImage, for: .normal)
let thumbImageHighlighted = UIImage(systemName: "circle", withConfiguration: thumbImageConfig)
customSlider.setThumbImage(thumbImageHighlighted, for: .highlighted)
customSlider.minimumValue = 0
customSlider.maximumValue = 100
customSlider.isContinuous = false
customSlider.value = 84
customSlider.addTarget(self, action: #selector(SliderViewController.sliderValueDidChange(_:)), for: .valueChanged)
}
Use a UISearchBar
for receiving search-related information from the user. There are various ways to customize the look of the search bar:
- Add a cancel button.
- Add a bookmark button.
- Set the bookmark image, both normal and highlighted states.
- Change the tint color that applies to key elements in the search bar.
- Set the search bar's background image.
The configureSearchBar
function sets up a custom search bar:
func configureSearchBar() {
searchBar.showsCancelButton = true
searchBar.showsBookmarkButton = true
searchBar.tintColor = UIColor.systemPurple
searchBar.backgroundImage = UIImage(named: "search_bar_background")
// Set the bookmark image for both normal and highlighted states.
let bookImage = UIImage(systemName: "bookmark")
searchBar.setImage(bookImage, for: .bookmark, state: .normal)
let bookFillImage = UIImage(systemName: "bookmark.fill")
searchBar.setImage(bookFillImage, for: .bookmark, state: .highlighted)
}
This sample shows how to customize a UIToolbar
, a specialized view that displays one or more buttons along the bottom edge of your interface. Customize a toolbar by determining its bar style (black or default), translucency, tint color, and background color.
The following viewDidLoad
function in CustomToolbarViewController
sets up a tinted tool bar:
override func viewDidLoad() {
super.viewDidLoad()
// See the `UIBarStyle` enum for more styles, including `.Default`.
toolbar.barStyle = .black
toolbar.isTranslucent = false
toolbar.tintColor = UIColor.systemGreen
toolbar.backgroundColor = UIColor.systemBlue
let toolbarButtonItems = [
refreshBarButtonItem,
flexibleSpaceBarButtonItem,
actionBarButtonItem
]
toolbar.setItems(toolbarButtonItems, animated: true)
}
CustomToolbarViewController
demonstrates further customization by changing the toolbar's background image:
override func viewDidLoad() {
super.viewDidLoad()
let toolbarBackgroundImage = UIImage(named: "toolbar_background")
toolbar.setBackgroundImage(toolbarBackgroundImage, forToolbarPosition: .bottom, barMetrics: .default)
let toolbarButtonItems = [
customImageBarButtonItem,
flexibleSpaceBarButtonItem,
customBarButtonItem
]
toolbar.setItems(toolbarButtonItems, animated: true)
}
Use a UIPageControl
to structure your app's user interface. A page control is a specialized control that displays a horizontal series of dots, each of which corresponds to a page in the app’s document or other data-model entity. You customize a page control by setting its tint color for all the page indicator dots, and for the current page indicator dot.
The configurePageControl
function sets up a customized page control:
func configurePageControl() {
// The total number of available pages is based on the number of available colors.
pageControl.numberOfPages = colors.count
pageControl.currentPage = 2
pageControl.pageIndicatorTintColor = UIColor.systemGreen
pageControl.currentPageIndicatorTintColor = UIColor.systemPurple
pageControl.addTarget(self, action: #selector(PageControlViewController.pageControlValueDidChange), for: .valueChanged)
}
You can attach menus to controls like UIButton
and UIBarButtonItem
. Create menus with the UIAction
class, and attach a menu to each control by setting the UIMenu
property.
Attach a menu to a UIButton
as shown here:
func configureMenuButton() {
let buttonTitle = NSLocalizedString("Button", comment: "")
menuButton.setTitle(buttonTitle, for: .normal)
let items = (1...5).map {
UIAction(title: String(format: NSLocalizedString("ItemTitle", comment: ""), $0.description), handler: menuHandler)
}
menuButton.menu = UIMenu(title: NSLocalizedString("ChooseItemTitle", comment: ""), children: items)
menuButton.showsMenuAsPrimaryAction = true
}
Create a UIBarButtonItem
with a menu attached as shown here:
var customTitleBarButtonItem: UIBarButtonItem {
let buttonMenu = UIMenu(title: "",
children: (1...5).map {
UIAction(title: "Option \($0)", handler: menuHandler)
})
return UIBarButtonItem(image: UIImage(systemName: "list.number"), menu: buttonMenu)
}