编辑代码

//
//	ContentView.swift	
//	LoginSwiftUI	
//
//	Created by Zhifeng Chen on 2020/8/1.	
//	Copyright  @ 2020 Zhifeng Chen. All rights reserved.	
//
import SwiftUI
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
.padding0//四周间隔 
Divider()
.background(Color(brown))//背景色为brown 
Image(systemName:"person")//系统图像person
.resizable()//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 50
VStack {
TextField("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
TextField("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()//四周默认间隔

Button(action: {
print("被点击了...")
}, label: {Text("登录")})
.padding()

Spacer()
}
}
}

struct ContentView_Previews: PreviewProvider {
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 SwiftUI
let lightGrayColor = Color(red: 239.0/255.0, green: 243.0/255.0, blu244.0/255.0,opacity: 1.0)
struct ContentView :View {
//保存输入的用户名
@State var userName :String=""
//保存输入的密码
@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))//背景色为brown 
Image("back02")//图片back02.png
.resizable()//允许改变图像尺寸
.frame(width:150,height:150)//尺寸改为150*150
.cornerRadius(150)// 圆角半径 50

VStack {
TextField("请输入用户名", text: $userName)
.padding()//四周默认间福
.padding(.leading,10)//前方间隔10
.background(lightGrayColor)//背景色
.cornerRadius(15)//圆角半径15
TextField("请输入密码", text: $passWord)
.padding()//四周默认问隔
.padding(.leading,10)//前方间隔10
.background(lightGrayColor)//背景色
.cornerRadius(15)//圆角半径15
}
·padding()//四周默认间隔

Button(action: {
if self.userName == "Zfchen" && self.passWord == "123" {
self.alertFlag = true
self.alertMsg = "登录成功"
}
else {
self.alertFlag = true
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("登录提示"), message: Text(self.alertMsg), dismissButton: .default(Text("确定")))
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}