在SwiftUI中开始编辑文本字段时检索键盘高度
在SwiftUI中开始编辑文本字段时检索键盘高度
提问于 2020-07-26 23:42:50
因此，我有一个类，它具有一个名为keyboardHeight的已发布变量，用于检索keyboardHeight的值：
import UIKit
class KeyboardHeightHelper: ObservableObject {
@Published var keyboardHeight: CGFloat = 0
init() {
self.listenForKeyboardNotifications()
}
private func listenForKeyboardNotifications() {
NotificationCenter.default.addObserver(forName: UIResponder.keyboardDidShowNotification,
object: nil,
queue: .main) { (notification) in
guard let userInfo = notification.userInfo,
let keyboardRect = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else { return }
self.keyboardHeight = keyboardRect.height
}
NotificationCenter.default.addObserver(forName: UIResponder.keyboardDidHideNotification,
object: nil,
queue: .main) { (notification) in
self.keyboardHeight = 0
}
}
}然后，在ContentView中，我只有一个TextField，当你开始/停止编辑字段时，它应该打印键盘高度：
import SwiftUI
struct ContentView: View {
@State var textFieldText = ""
@ObservedObject var keyboardHeightHelper = KeyboardHeightHelper()
var body: some View {
VStack {
TextField("Text field",
text: $textFieldText, onEditingChanged: { _ in print("the keyboard height is \(self.keyboardHeightHelper.keyboardHeight)") })
}
}
}我遇到的问题是:当我没有编辑文本字段，然后单击它时，它会打印键盘高度为0.0 (我猜这是因为它在显示键盘之前获取了keyboardHeight值，所以此时高度是0.0，因为看不到键盘)。当我按return键时，键盘的高度(对于iPhone 8模拟器)打印为260.0的正确值。我的问题是，当我开始编辑时，如何访问键盘的值？
Stack Overflow用户
发布于 2020-07-26 23:58:53
尝尝这个。您可以只使用SwiftUI视图的一个修饰符来集成它：
extension UIResponder {
static var currentFirstResponder: UIResponder? {
_currentFirstResponder = nil
UIApplication.shared.sendAction(#selector(UIResponder.findFirstResponder(_:)), to: nil, from: nil, for: nil)
return _currentFirstResponder
}
private static weak var _currentFirstResponder: UIResponder?
@objc private func findFirstResponder(_ sender: Any) {
UIResponder._currentFirstResponder = self
}
var globalFrame: CGRect? {
guard let view = self as? UIView else { return nil }
return view.superview?.convert(view.frame, to: nil)
}
}extension Publishers {
static var keyboardHeight: AnyPublisher<CGFloat, Never> {
let willShow = NotificationCenter.default.publisher(for: UIApplication.keyboardWillShowNotification)
.map { $0.keyboardHeight }
let willHide = NotificationCenter.default.publisher(for: UIApplication.keyboardWillHideNotification)
.map { _ in CGFloat(0) }
return MergeMany(willShow, willHide)
.eraseToAnyPublisher()
}
}
extension Notification {
var keyboardHeight: CGFloat {
return (userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect)?.height ?? 0
}
}struct KeyboardAdaptive: ViewModifier {
@State private var bottomPadding: CGFloat = 0
func body(content: Content) -> some View {
GeometryReader { geometry in
content
.padding(.bottom, self.bottomPadding)
.onReceive(Publishers.keyboardHeight) { keyboardHeight in
let keyboardTop = geometry.frame(in: .global).height - keyboardHeight
let focusedTextInputBottom = UIResponder.currentFirstResponder?.globalFrame?.maxY ?? 0
self.bottomPadding = max(0, focusedTextInputBottom - keyboardTop - geometry.safeAreaInsets.bottom)
}
.animation(.easeOut(duration: 0.16))
}
}
}
extension View {
func keyboardAdaptive() -> some View {
ModifiedContent(content: self, modifier: KeyboardAdaptive())
}
}用法：
struct ContentView: View {
@State private var text = ""
var body: some View {
VStack {
Spacer()
TextField("Enter something", text: $text)
.textFieldStyle(RoundedBorderTextFieldStyle())
}
.padding()
.keyboardAdaptive()//note this
}
}向多个在线来源致谢。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/63102304
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