SwiftUI Xcode-based ios development study notes No.1 login interface

Is me me or me
SwiftUI is a framework for ios development using swift language
Different from Objective-C
Synchronous learning with Obejctive-C and Android Studio using Java language

layout

First look at an error:

Function declares an opaque return type, but has no return statements in its body from which to infer an underlying type：

The reason is that only one layout can exist in
var body: some View { } , and any more content will report an error; therefore, we can only nest designs in a large layout.

HStack is placed horizontally, VStack is placed vertically

Add components

In the past, android can drag and drop components in the xml file to complete the UI design, and use the objective-c ios development to complete the UI design through the storyboard drag and drop components; both can be separated from the graphical interface and the code.
The current way is to write the code/drag and drop the component to automatically generate the code, and then preview the current layout design on the canvas next to it.

Common components

Label

Text("手机软件开发") // 是一个label

@State var account: String = "" //变量声明
@State var password: String = ""

TextField

HStack {
    
    
                Image(systemName: "person")
                TextField("用户名", text: $account, onCommit: {
    
    
                })
            }.padding(.all, 25.0)

Button and action event writing

Button(action: {
    
    
                    print("login action")
                }) {
    
    
                    Text("登陆")
                }.padding(.all, 25.0)

interface

The main interface is in the ContentView.swift file.
Corresponding to MainActivity of Android and Main.storyboard of OC-based ios?
(Review: Multiple interfaces
OC-based ios development is to create ViewController,
Android is to create Activity.java, and the activity element must be declared in the AndroidManifest.xml file)

Variables and constants

normal constant
@state variable

Page jump

Review: In the
OC-based ios development, the segue between the control and the ViewController in the storyboard mode is directly completed in the
Android Studio. In the android development: use intent to jump

Use NavigationView in SwiftUI

NavigationView {
    
    
            NavigationLink(
                destination: LoginView(),isActive: $loginAccountIsActive){
    
    
                    Text("点我跳转")
                }
            
        }

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Realize the effect:

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