【发布时间】：2020-03-09 19:34:59
【问题描述】：
我一直在努力学习 swift，并决定构建一个小型 BMI 计算器以适应一切。我以为我已经弄清楚了一切，但由于某种原因，它每次都返回 0。我不太明白为什么。我觉得这可能与 @State var s 有关，但是我不确定是否因为那些不适合 textinputs 的似乎只是找到了。
这就是我所拥有的：
import SwiftUI
struct ContentView: View {
@State var heightFeet: String = ""
@State var heightInches: String = ""
@State var weight: String = ""
@State var bmi: String = ""
@State var bmiText: String = ""
@State var bmiDetail: String = ""
var body: some View{
VStack {
VStack {
VStack {
Text("BMI Calculator")
.font(.largeTitle)
.padding(.top)
.foregroundColor(Color.white)
}
.frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: 100)
.background(Color.black)
.shadow(radius: 10)
VStack {
TextField("Enter height in feet", text: $heightFeet)
.padding(.all)
.frame(width: 300)
.textFieldStyle(RoundedBorderTextFieldStyle())
.background(Color.clear)
.foregroundColor(.black)
.shadow(radius: 5)
.keyboardType(.numberPad)
TextField("Enter height in inches", text: $heightInches)
.padding(.all)
.frame(width: 300)
.textFieldStyle(RoundedBorderTextFieldStyle())
.background(Color.clear)
.foregroundColor(.black)
.shadow(radius: 5)
.keyboardType(.numberPad)
TextField("Enter weight", text: $weight)
.padding(.all)
.frame(width: 300)
.textFieldStyle(RoundedBorderTextFieldStyle())
.background(Color.clear)
.foregroundColor(.black)
.shadow(radius: 5)
.keyboardType(.numberPad)
}
.frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity)
.background(Color.gray)
VStack {
Text(bmiText)
.font(.title)
.foregroundColor(Color.black)
Text(bmi)
.font(.largeTitle)
.foregroundColor(Color.black)
Text(bmiDetail)
.padding(.all)
.font(.headline)
.foregroundColor(.black)
}
.frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity)
.padding()
}
HStack {
Button(action: {
let heightInFeet = Int(self.heightFeet)
let heightInInches = Int(self.heightInches)
let weights = Int(self.weight)
let height = Int(heightInFeet! * 12 + heightInInches!)
let bmis = Int(weights! / (height * height) * 703)
self.bmi = "\(bmis)%"
self.bmiText = "Your BMI is"
if bmis > 30{
self.bmiDetail = "You are considered to be obese."
}
else if bmis > 25{
self.bmiDetail = "You are considered to be overweight."
}
else{
self.bmiDetail = "You are healthy!"
}
}) {
HStack {
Image(systemName: "plus.square")
Text("Calculate")
}
.frame(minWidth: 0, maxWidth: .infinity)
.font(.title)
.padding(.horizontal, 60.0)
.padding(.vertical, 20)
.background(Color("button"))
.cornerRadius(10)
.foregroundColor(Color.black)
.shadow(radius: 5)
.padding(.vertical, 40)
.padding(.horizontal, 20)
}
}
.background(Color.gray)
}
.frame(minWidth:0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity)
.background(Color.gray)
.edgesIgnoringSafeArea(.all)
.onTapGesture {
self.endTextEditing()
}
}
}
extension View {
func endTextEditing() {
UIApplication.shared.sendAction(#selector(UIResponder.resignFirstResponder),
to: nil, from: nil, for: nil)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
【问题讨论】：
-
你不应该用整数来计算。或者至少先乘以
703，然后再除以(height * height)