[英]UIViewRepresentable view not updating value
我正在尝试创建自定义 SwiftUI 视图,但在通过 ObservedObject 更新值时遇到问题。
import SwiftUI
import Combine
struct ContentView: View {
@ObservedObject var model:InfoViewModel = InfoViewModel()
var body: some View {
VStack(alignment: .leading){
CustomView(value: self.model.title)
.frame(width: 200, height: 200, alignment: .center)
}
.background(Color.green)
.frame(minWidth: 0,
maxWidth: .infinity,
minHeight: 0,
maxHeight: .infinity,
alignment: .topLeading)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
struct CustomView: UIViewRepresentable {
typealias UIViewType = UIView
var value:String
var lblTitle:UILabel = UILabel()
func makeUIView(context: Context) -> UIView {
let view:UIView = UIView()
view.addSubview(lblTitle)
lblTitle.text = value
lblTitle.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
lblTitle.backgroundColor = UIColor.red
lblTitle.textColor = UIColor.black
return view
}
func updateUIView(_ uiView: UIView, context: Context) {
self.lblTitle.text = value
print("LBLTitle:\(self.lblTitle.text!)\nTitleValue:\(self.value)")
}
}
class InfoViewModel: ObservableObject, Identifiable {
@Published var title = "Title"
private var count = 0
init() {
_ = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(fireTimer), userInfo: nil, repeats: true)
}
@objc func fireTimer() {
count += 1
self.title = "\(self.count)"
print("Timer fired!\n\(self.title)")
}
}
编辑:我在@Asperi 回答之后更改了代码,现在它正在更新值。 但正如 Dávid Pásztor 所建议的那样,在 struct 中创建 @ObservedObject 是不对的,那么我将如何通过创建 @ObservedObject 和链接将值传递给 CustomView,而 David 提供的链接是旧的,并且该线程中的代码现在似乎不起作用。
这是正在运行的代码
struct CustomView: UIViewRepresentable {
typealias UIViewType = UIView
var value:String
func makeUIView(context: Context) -> UIView {
let view:UIView = UIView()
let lblTitle:UILabel = UILabel()
view.addSubview(lblTitle)
lblTitle.text = value
lblTitle.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
lblTitle.backgroundColor = UIColor.red
lblTitle.textColor = UIColor.black
return view
}
func updateUIView(_ uiView: UIView, context: Context) {
for view in uiView.subviews
{
if(view.isKind(of: UILabel.self))
{
(view as! UILabel).text = value
print("LBLTitle:\((view as! UILabel).text!)\nTitleValue:\(self.value)")
}
}
}
}
您不需要将其保留为属性,因为 struct 可以重新创建(因此您可以丢失它),相反您可以通过参数中提供的方式访问您的视图。
注意: UIViewRepresentable
处理对相应视图的引用。
struct CustomView: UIViewRepresentable {
typealias UIViewType = UILabel
var value:String
func makeUIView(context: Context) -> UILabel {
let lblTitle = UILabel()
lblTitle.text = value
lblTitle.backgroundColor = UIColor.red
lblTitle.textColor = UIColor.black
return lblTitle
}
func updateUIView(_ uiLabel: UILabel, context: Context) {
uiLabel.text = value
}
}
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