第1年6月30日 swiftui playgrounds

1.

import SwiftUI
import PlaygroundSupport

struct ContentView : View {
    @State var index = 0
    var body: some View {
    
        VStack{
            Text("hello world")
            .padding()
            Text("(self.index)")
                .padding()
            
            Button("tap me"){
                self.index = self.index+1
            }
        }
    }
    
}


PlaygroundPage.current.setLiveView(ContentView())

https://www.jianshu.com/p/00eeafbfc163

import UIKit

func sortArr(_ nums: [Int]) -> ([Int]) 
{
    var nums = nums
    for i in 0..<nums.count {
        for j in 0..<nums.count-i-1 {
            if(nums[j]>nums[j+1]) {
                let temp = nums[j]
                nums[j] = nums[j+1]
                nums[j+1] = temp
            }
        }
    }
    return nums
}

class NumWrap {

    var nums: [Int] = []
    
    init(nums:[Int]) {
        self.nums = nums
    }
    
    func sort(){
        self.nums = sortArr(self.nums)
    }
    
    func toString() -> (String) {
        var text = ""
        for i in 0..<nums.count{
            text += "(nums[i]),"
        }
        
        return text
    }
}


var nums = [2,4,1,5,3]
print("排序前:",nums)
print("排序后:",sortArr(nums))

let num = NumWrap(nums: nums)

print(num.toString())

import SwiftUI
import PlaygroundSupport

struct ContentView : View {
    @State  var index = 0
    @State  var text = ""
    var num: NumWrap
    
    init(num:NumWrap) {
        self.num = num
        _text = State(initialValue: num.toString())
    }
    
    var body: some View {
        
        VStack(spacing:10){
            Text("(self.text)")
                .padding()
            Text("(self.index)")
                .padding()
            
            Button("sort") {
                self.num.sort()
                self.text = "排序后:"
                self.text += self.num.toString()
            }.padding()
            Button("tap me") {
                
                self.index = self.index+1
            }.padding()
        }
    }
    
}

var view = ContentView(num:num )
PlaygroundPage.current.setLiveView(view)

初始化@state

https://zhuanlan.zhihu.com/p/266137663