编辑代码

//
//ContentView.swift
//LoginSwiftUI
//
//Created by Zhifeng Chen on 2020/8/1.
//Copyright @ 2020 Zhifeng CHen. All rights reserved.
//
import SwifrUI
struct ContentView : View {
    @State var userName : String =""
    @State var passWord : String =""

    var body: some View {
        VStack {
            Text("欢迎使用找不同")
            .font(.title)//字体大小为标题
            .padding()//四周间隔
            Divider()
            .background(Color(.brown))//背景颜色为brown
            Image(systemName:"person")//系统图像person
            .resizeable()//允许改变图像尺寸
            .frame(width: 150, height: 150)//尺寸改为150*150
            .cornerRadius(50)//圆角半径
            VStack {
                TextFied("请输入用户名", text: $userName)
                .padding()//四周默认间隔
                .padding(.leading,10)//前方间隔10
                .background(Color(.lightGray))//背景色
                .cornerRadius(15)//圆角半径15
                TextFied("请输入密码", text: $passWord)
                .padding()//四周默认间隔
                .padding(.leading,10)//前方间隔10
                .background(Color(.lightGray))//背景色
                .cornerRadius(15)//圆角半径15
            }
            .padding() 
            Button(action: {
                print("被点击了……")
            }, label: {Text("登录")})
                .padding()
            Spacer()
        }
    }
}

struct ContentView_PreviewProvide {
    static var previews: some View {
        ContentView()
    }
}

//
//ContentView.swift
//LoginSwiftUI
//
//Created by Zhifeng Chen on 2020/8/1.
//Copyright @ 2020 Zhifeng CHen. All rights reserved.
//
import SwifrUI
let lightGrayColor = Color(red: 239.0/255.0, green: 243.0/255.0, blue: 244.0/255.0, opacity: 1.0)
struct ContentView : View {
    //保存输入的用户名
    @State var userName : String = ""
    //保存输入密码
    @State var passWord : String = ""
    //是否需要弹出Alert窗口
    @State private var alertFlag : Bool = false
    //弹出窗口里面的具体内容
    @State private var alertMsg : String = ""
    var body: some View {
        VStack {
            Text("欢迎使用找不同")
            .font(.title)//字体大小为标题
            .padding()//四周间隔
            Divider()
            .background(Color(.brown))//背景颜色为brown
            Image(systemName:"person")//系统图像person
            .resizeable()//允许改变图像尺寸
            .frame(width: 150, height: 150)//尺寸改为150*150
            .cornerRadius(50)//圆角半径
            VStack {
                TextFied("请输入用户名", text: $userName)
                .padding()//四周默认间隔
                .padding(.leading,10)//前方间隔10
                .background(Color(.lightGray))//背景色
                .cornerRadius(15)//圆角半径15
                TextFied("请输入密码", text: $passWord)
                .padding()//四周默认间隔
                .padding(.leading,10)//前方间隔10
                .background(Color(.lightGray))//背景色
                .cornerRadius(15)//圆角半径15
            }
            .padding() 
            Button(action: {
                if self.userName == "Zfchen" && self.passWord == "123" {
                    self.alertFlag = ture
                    self.alertMsg = "登录成功"
                }
                else {
                    self.alertFlag = ture
                    self.alertMsg = "登录失败"
                }
            }, label:{
                Text("登录")
                .font(.headline)
                .foregroundColor(.white)
                .frame(width: 220, height: 60)
                .background(Color.green)
                .cornerRadius(15.0)
            })
            .padding()
            Spacer()
        }
        .alert(isPresented: $alertFlag) { () -> Alert in 
        Alert(title: Text("登录提醒"), message: Text(self.alertMsg), dismissButton: .default(Text("确定")))
        }
    }
}
struct ContentView_PreviewProvide: PreviewProvide {
    static var previews: some View {
        ContentView()
    }
}