swiftUI在计算ZStack元素的数据之前运行函数的同步问题

问题描述

我正在使用SwiftUI,但是有一个概念上的问题。

我已经修改了我的代码(希望可以完全解释该问题)

我想在按下按钮之后进行一些计算,以绘制图形。

我使用minX作为计算的虚假结果。

首先,请注意我有一个文件(称为myGlobal.swift),其内容为:

import Foundation
class myGlobalVariables: ObservableObject
{
    @Published var minX     :Double =  99999
}

getLineChartDataSet中的此值= 9999 (来自全局文件) 在我按下按钮之前

在Mohrs2DCalc函数中将按钮按下至222.222之后,情况发生了变化 但是,当然,在按下按钮之前,我已经运行过myLineChartSwiftUI, 但是只想在我按下按钮之后运行myLineChartSwiftUI

import SwiftUI
import Charts
struct PricipalStresses2D: View {

 @Observedobject var input = myGlobalVariables()
var body: some View
{
    
    ScrollView(.vertical,showsIndicators: true)
    {
        vstack(spacing: -10)
        {


                Button(action: {
                    self.CheckInputs()
                })
                {
                        Text("Calculations Before Plot")
            }.padding(50)
            
            
                  myLineChartSwiftUI()  //use frame to change the graph size within your SwiftUI view
                      .frame(alignment: .center)
                      .aspectRatio(contentMode: .fit)
        }
    }
}

func CheckInputs()
{
    //Assume all inputs are OK
        self.Mohrs2DCalc()
}


func Mohrs2DCalc()
{
    let minX = 222.222 // Just to set it as if we had calculated it
    self.input.minX = minX
    print("Mohrs circle minX = \(self.input.minX)")
}



struct myLineChartSwiftUI : UIViewRepresentable
{
    let lineChart = LineChartView()
    func makeUIView(context: UIViewRepresentableContext<myLineChartSwiftUI>) -> LineChartView {
        setUpChart()
        return lineChart
    }
    func updateUIView(_ uiView: LineChartView,context: UIViewRepresentableContext<myLineChartSwiftUI>) {
    }
    func setUpChart() {
        
        //lineChart.noDataText = "No Data Available"
        let dataSets = [getLineChartDataSet()]
        let data = LineChartData(dataSets: dataSets)
        //data.setValueFont(.systemFont(ofSize: 7,weight: .light))
        lineChart.data = data
    }
    func getChartDataPoints(sessions: [Int],accuracy: [Double]) -> [ChartDataEntry] {
        var dataPoints: [ChartDataEntry] = []
        for count in (0..<sessions.count) {
            dataPoints.append(ChartDataEntry.init(x: Double(sessions[count]),y: accuracy[count]))
        }
        return dataPoints
    }
    func getLineChartDataSet() -> LineChartDataSet {
        print("In getLineChartDataSet,minX = ",myGlobalVariables.self.init().minX) // This works fine
        
        let dataPoints = getChartDataPoints(sessions: [0,1],accuracy: [0.0,10.0])  // sessions = x,accuracy = y
        let set = LineChartDataSet(entries: dataPoints,label: "DataSet")
        set.linewidth = 0
        //set.circleRadius = 4
        //set.circleHoleRadius = 2
        let color = ChartColorTemplates.vordiplom()[4]
        set.setColor(color)
        //set.setCircleColor(color)
        
// Got to set the xMin and xMax from the global to obtain it here
 
        
        return set
    }
}

} //View
    
    
struct PricipalStresses2D_Previews: PreviewProvider {
static var previews: some View {
    PricipalStresses2D()
}
}

您的帮助将不胜感激, TIA,菲尔。

解决方法

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