如何在 SwiftUI 中以编程方式编辑 TextField 的边框颜色？

这是代码片段：

TextField("Email", text: self.$email)
    .padding()
    .overlay(RoundedRectangle(cornerRadius: 1)
                .stroke(Color.black, lineWidth: 1))
SecureField("Password", text: self.$password)
    .padding()
    .overlay(RoundedRectangle(cornerRadius: 1)
                .stroke(Color.black, lineWidth: 1))

Button(action: {
    print("The button was clicked!")
    if loginAndPasswordAreOK() {
        print("Login & Password are OK!")
    } else {
        self.email = ""
        self.password = ""
    }
}, label: {
Text("Log In")
    .fontWeight(.bold)
    .padding()

如果登录名和密码输入不正确，如何将电子邮件文本字段边框颜色更改为红色？

您可以为此使用显式状态变量，例如

@State private var isValid = true

...

TextField("Email", text: self.$email)
    .padding()
    .overlay(RoundedRectangle(cornerRadius: 1)
                .stroke(isValid ? Color.black : Color.red, lineWidth: 1))

...
Button(action: {
    print("The button was clicked!")
    isValid = loginAndPasswordAreOK() 
    if isValid {
     ...