问题描述
我正在尝试创建自定义的SwiftUI视图,但是在通过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)")
}
}
Project can be download from here
编辑: 我在@Asperi回答后更改了代码,现在它正在更新值。但是正如DávidPásztor所建议的那样,在结构内部创建@Observedobject是不正确的,那么我将如何通过创建@Observedobject并将该值传递给CustomView以及David提供的链接已经很旧,并且该线程中的代码现在似乎无法正常工作。
这是有效的代码
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,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)")
}
}
}
}
解决方法
您无需将其保留为属性,因为可以重新创建struct(因此可以松开它),而可以通过参数中提供的方式访问视图。
注意:false
自己处理对相应视图的引用。
UIViewRepresentable