Gestalt is an unintrusive and light-weight framework for application theming with support for animated theme switching.
Let's say you want to theme a view controller with a single label:
import Gestalt
struct Theme: ThemeProtocol {
let font = UIFont.preferredFont(forTextStyle: .headline)
let color: UIColor
let backgroundColor: UIColor
static let light = Theme(
color: UIColor.black
backgroundColor: UIColor.white
)
static let dark = Theme(
color: UIColor.white
backgroundColor: UIColor.black
)
}
// In `AppDelegate.application(_:didFinishLaunchingWithOptions:)`
// assign a default theme (or user's choice from user defaults):
ThemeManager.default.theme = Theme.light
class ViewController: UIViewController {
@IBOutlet var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
ThemeManager.default.apply(theme: Theme.self, to: self) { themeable, theme in
themeable.view.backgroundColor = theme.backgroundColor
themeable.label.textColor = theme.color
themeable.label.font = theme.font
}
}
}
A call to ThemeManager.apply(theme:to:animated:closure:)
registers the closure passed to it on the given ThemeManager
for future theme changes and then calls it once immediately. If you want the initial call to be animated, make sure to pass …, animated: true, …
to it (the default is false
).
To change the current theme (even while the app is running) simply assign a different theme to your given ThemeManager
in use:
ThemeManager.default.theme = Theme.dark
This will cause all previously registered closures on the given ThemeManager
to be called again.
- It is generally sufficient to use
ThemeManager.default
. It is however possible to create dedicatedThemeManager
s vialet manager = ThemeManager()
. - The value passed to
animated
overrides theThemeManager
's default setting ofvar animated: Bool
for the initial call of the closure.
- Within
closure
any access onthemeable
should only achieved through the closure's$0
argument, not directly, to avoid retain cycles. - The body of
closure
should be idempotent to avoid unwanted side-effects on repeated calls.
The recommended way to add Gestalt to your project is via Carthage:
github 'regexident/Gestalt'
or via Cocoapods:
pod 'Gestalt'
Gestalt is available under the MPL-2.0 license. See the LICENSE
file for more info.