在SwiftUI中,可以使用onReceive
修饰符来检测键盘按键的事件。具体步骤如下:
import SwiftUI
import Combine
ObservableObject
的类,用于存储键盘事件的状态:class KeyboardObserver: ObservableObject {
@Published var key: String = ""
init() {
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: Notification) {
if let key = notification.userInfo?[UIResponder.keyboardIsLocalUserInfoKey] as? Bool, key {
self.key = "Keyboard is shown"
}
}
@objc func keyboardWillHide(notification: Notification) {
if let key = notification.userInfo?[UIResponder.keyboardIsLocalUserInfoKey] as? Bool, key {
self.key = "Keyboard is hidden"
}
}
}
onReceive
修饰符来监听键盘事件,并更新状态:struct ContentView: View {
@ObservedObject var keyboardObserver = KeyboardObserver()
var body: some View {
VStack {
Text(keyboardObserver.key)
.padding()
Spacer()
}
.onReceive(NotificationCenter.default.publisher(for: UIResponder.keyboardWillShowNotification)) { _ in
self.keyboardObserver.keyboardWillShow(notification: Notification(name: UIResponder.keyboardWillShowNotification))
}
.onReceive(NotificationCenter.default.publisher(for: UIResponder.keyboardWillHideNotification)) { _ in
self.keyboardObserver.keyboardWillHide(notification: Notification(name: UIResponder.keyboardWillHideNotification))
}
}
}
在上述代码中,我们创建了一个KeyboardObserver
类,用于监听键盘的显示和隐藏事件。通过@Published
属性包装器,我们将key
属性声明为可观察的,以便在键盘事件发生时更新视图。
在ContentView
中,我们使用@ObservedObject
属性包装器将keyboardObserver
对象声明为视图的观察对象。然后,我们在视图的body
中显示keyboardObserver.key
属性的值,并使用onReceive
修饰符监听键盘的显示和隐藏事件。当键盘事件发生时,我们手动触发KeyboardObserver
类中的相应方法,并更新key
属性的值。
这样,当键盘显示时,Text
视图将显示"Keyboard is shown",当键盘隐藏时,将显示"Keyboard is hidden"。
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请注意,以上代码仅适用于SwiftUI中的键盘事件检测,不涉及云计算领域的相关知识。
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