KeyboardGuide - 一个现代、真实的iOS键盘系统通知处理程序框架

KeyboardGuide - 一个现代、真实的iOS键盘系统通知处理程序框架

KeyboardGuide

A modern, real iOS keyboard system notifications handler framework that Just Works.

As you know, handling the keyboard on iOS was just a nightmare.

On the internet, there are many, many iOS keyboard handler implementations for system notifications such as UIResponder.keyboardWillChangeFrameNotification (UIKeyboardWillChangeFrameNotification), but most of them are not implemented properly.

For example, many of them are not converting the keyboard frame in the right coordinate or not considering iPad keyboard behaviors. Also, there are many undocumented behaviors that are not consistent between each iOS version.

This framework is solving this problem.

Based on years experience of iOS application development and various tests on each iOS version and device, it supports both Swift and Objective-C and works mostly reasonably on the latest 3 versions of iOS, which is iOS 11, 12 and iOS 13 now, and covers almost all iOS users.

Usage

Using KeyboardGuide is really simple. See also Examples for actual usage, that contains Swift and Objective-C code for testing.

Add KeyboardGuide framework to your project

Add the following lines to your Package.swift or use Xcode “Add Package Dependency…” menu.

// In your `Package.swift`dependencies: [ // ... .package(url: "https://github.com/niw/KeyboardGuide.git"), // ...]

Setup KeyboardGuide

Add import KeyboardGuide.

Use KeyboardGuide.shared.activate() to activate KeyboardGuide at the beginning of application life cycle, such as application(_:didFinishLaunchingWithOptions:).

// In your `UIApplicationDelegate`func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { KeyboardGuide.shared.activate() // ...}

Add constraints on your views

Lay out your views by adding constraints to view.keyboardSafeArea.layoutGuide, where represents the safe area from, not covered by the keyboard.

It works as like safeAreaLayoutGuide for the notch.

// In your `UIViewController`override func viewDidLoad() { super.viewDidLoad() // ... let textView = UITextView() textView.translatesAutoresizingMaskIntoConstraints = false // ... textView.bottomAnchor.constraint(equalTo: view.keyboardSafeArea.layoutGuide.bottomAnchor).isActive = true // ...}

Manual layout

If you prefer to manually lay out your views or need to use length of keyboard safe area, for such as updating UIScrollView's contentInset, override viewDidLayoutSubviews() or layoutSubviews() as like regular manual lay outing.

// In your `UIViewController`override func viewDidLayoutSubviews() { super.viewDidLayoutSubviews() // ... let bottomInset = view.keyboardSafeArea.insets.bottom textView.contentInset.bottom = bottomInset textView.scrollIndicatorInsets.bottom = bottomInset}

The important layout behavior

If your view doesn’t have any sub views that have at least one constraint to view.keyboardSafeArea.layoutGuide, UIKit MAY NOT call layoutSubviews (or similar callbacks such as viewDidLayoutSubviews).

Because in general, the keyboard safe area has a relative layout relationship between the keyboard position where is outside of the view but in the screen, UIKit doesn’t know that relationship without a constraint.

For example, on iOS 13, if a view controller is presented as a modal on iPad in portrait, when the keyboard is appearing, that modal view controller is moved upwards by UIKit. This move changes the relative position of your view to the keyboard, however, UIKit doesn’t call your layoutSubviews (which is obvious,) but for keyboard safe area, you MAY need to re lay out your sub views.

Therefore, you MAY need to add at least one constraint to view.keyboardSafeArea.layoutGuide from one of your sub views, to let UIKit knows view has that relationship.

Known limitations

There are a few known limitations in the current implementation. All limitations are currently To-Do of this project.

No SwiftUI support yet. Share extension can’t use this library yet because of UIApplication dependency. Objective-C code can’t @import KeyboardGuide by using Swift Package Manager. This is known, Swift Package Manager limitation prior to Swift 5.2, Xcode 11.4. Use Xcode 11.4, if this limitation is a problem for you.

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