Swiftui 动态更改基础货币
我有一个货币API,它返回一个JSON对象,其中包含一个奇怪的排列:基本货币用作标签。典型的货币API有“基准”、“日期”、“成功”和“利率”等标签,但此API没有这些标签Swiftui 动态更改基础货币,swiftui,ios14,Swiftui,Ios14,我有一个货币API,它返回一个JSON对象,其中包含一个奇怪的排列:基本货币用作标签。典型的货币API有“基准”、“日期”、“成功”和“利率”等标签,但此API没有这些标签 { "usd": { "aed": 4.420217, "afn": 93.3213, "all": 123.104693, "amd": 628.026
{
"usd": {
"aed": 4.420217,
"afn": 93.3213,
"all": 123.104693,
"amd": 628.026474,
"ang": 2.159569,
"aoa": 791.552347,
"ars": 111.887966,
"aud": 1.558363,
"awg": 2.164862,
"azn": 2.045728,
"bam": 1.9541,
"bbd": 2.429065,
"bch": 0.001278
}
}
顶部的“usd”(美元)称为基础货币或本国货币。目前,存储结构和状态参数被硬编码为“usd”,这将阻止使用与其他基础货币的汇率。汇率API对于美元这一基础货币非常有效
我需要帮助修改东西,以便我可以下载不同基础货币的汇率。例如,我可以在存储模型和状态参数中使用字符串变量吗?任何启迪都将不胜感激
struct RateResult: Codable {
let usd: [String: Double]
}
@State private var results = RateResult(usd: [:])
struct ContentView: View {
var body: some View {
}
func UpdateRates() {
let baseUrl = "https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api@1/latest/currencies/"
let baseCur = baseCurrency.baseCur.baseS // usd
let requestType = ".json"
guard let url = URL(string: baseUrl + baseCur + requestType) else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
if let decodedResponse = try? JSONDecoder().decode(RateResult.self, from: data) {
// we have good data – go back to the main thread
DispatchQueue.main.async {
// update our UI
self.results = decodedResponse
// save off currency exchange rates
}
// everything is good, so we can exit
return
}
}
// if we're still here it means there was a problem
print("Currency Fetch Failed: \(error?.localizedDescription ?? "Unknown error")")
}.resume()
}
}
导入快捷界面
//你不能使用标准的可编码代码。你必须自己做。
类别基本货币:可编码{
设id=UUID()
var baseCurrencies:[字符串:[字符串:双精度]=[:]
必需的公共初始化(来自解码器:解码器)抛出{
做{
打印(#功能)
让baseContainer=try decoder.singleValueContainer()
let base=try baseContainer.decode([String:[String:Double]].self)
对于base.keys中的键{
基本货币[键]=基本货币[键]
}
}抓住{
打印(错误)
抛出错误
}
}
//@状态不应在作为视图的结构外部使用
}
结构CurrencyView:视图{
@StateObject变量vm:CurrencyViewModel=CurrencyViewModel()
var body:一些观点{
VStack{
名单{
如果vm.results!=nil{
ForEach(vm.results!.baseCurrencies.sorted{$0.key<$1.key},id:\.key){key,baseCurrency in
披露组(关键){
ForEach(baseCurrency.sorted{$0.key<$1.key},id:\.key){key,以
HStack{
文本(关键)
文本(费率说明)
}
}
}
}
}否则{
文本(“等待…”)
}
}
//选择另一个速率以进行提取
RatesPickerView().environmentObject(vm)
}.onAppear(){
vm.UpdateRates()
}
}
}
结构速率SpickerView:视图{
@EnvironmentObject变量vm:CurrencyViewModel
var body:一些观点{
如果vm.results!=nil{
//您可能会使用中的键填充此选择器
//baseCurrency.baseCur.baseS
选择器(“汇率”,选择:$vm.selectedBaseCurrency){
ForEach((vm.results!.baseCurrencies.first?.value.sorted{$0.key<$1.key})!,id:\.key){key,按
文本(键)。标记(键)
}
}
}否则{
文本(“等待…”)
}
}
}
类CurrencyViewModel:ObservableObject{
@公布的风险值结果:基准货币?
@已发布的var selectedBaseCurrency:String=“usd”{
迪塞特{
更新()
}
}
init(){
//如果可以的话。看来你不需要在这里
//更新()
}
func UpdateRates(){
打印(#功能)
让baseUrl=”https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api@1/最新/货币/”
设baseCur=selectedBaseCurrency//usd
let requestType=“.json”
guard let url=url(字符串:baseUrl+baseCur+requestType)else{
打印(“无效URL”)
返回
}
let request=URLRequest(url:url)
URLSession.shared.dataTask(with:request){data,response,中的错误
如果let data=data{
做{
让decodedResponse=try JSONDecoder().decode(BaseCurrency.self,from:data)
DispatchQueue.main.async{
如果self.results==nil{
//指定新的基础货币
self.results=解码响应
}else{//将现有结果与新结果合并
对于decodedResponse.baseCurrencies.keys中的base{
self.results?.baseCurrencies[base]=decodedResponse.baseCurrencies[base]
}
}
//更新用户界面
self.objectWillChange.send()
}
}抓住{
//尝试引发的错误
打印(错误)//信息量远大于错误?。本地化描述
}
}
如果错误!=nil{
//数据任务错误
打印(错误!)
}
}1.简历()
}
}
结构CurrencyView\u预览:PreviewProvider{
静态var预览:一些视图{
CurrencyView()
}
}
感谢lorem ipsum花时间研究这一点。这比我最初想象的更具挑战性!我想从onAppear(.onAppear(perform:CurrencyViewModel.UpdateRates())调用UpdateRates()方法,但我得到了错误“call中缺少参数#1的参数。修复:Insert”“。初始化逻辑没有参数。一定有更简单的方法,但我正在从主选项卡视图调用此货币逻辑,然后在一天几次更新货币汇率之前使用一些时钟逻辑进行检查。如果没有参数,我将无法知道发生了什么。”看到代码(.onAppear(perform:CurrencyViewModel.UpdateRates())
这看起来是错误的。开头的圆括号很粗略,您将它作为参数传递到某个对象中,而UpdateRates
没有
import SwiftUI
//You can't use the standard Codable for this. You have to make your own.
class BaseCurrency: Codable {
let id = UUID()
var baseCurrencies: [String : [String: Double]] = [:]
required public init(from decoder: Decoder) throws {
do{
print(#function)
let baseContainer = try decoder.singleValueContainer()
let base = try baseContainer.decode([String : [String: Double]].self)
for key in base.keys{
baseCurrencies[key] = base[key]
}
}catch{
print(error)
throw error
}
}
//@State should never be used outside a struct that is a View
}
struct CurrencyView: View {
@StateObject var vm: CurrencyViewModel = CurrencyViewModel()
var body: some View {
VStack{
List{
if vm.results != nil{
ForEach(vm.results!.baseCurrencies.sorted{$0.key < $1.key}, id: \.key) { key, baseCurrency in
DisclosureGroup(key){
ForEach(baseCurrency.sorted{$0.key < $1.key}, id: \.key) { key, rate in
HStack{
Text(key)
Text(rate.description)
}
}
}
}
}else{
Text("waiting...")
}
}
//To select another rate to go fetch
RatesPickerView().environmentObject(vm)
}.onAppear(){
vm.UpdateRates()
}
}
}
struct RatesPickerView: View {
@EnvironmentObject var vm: CurrencyViewModel
var body: some View {
if vm.results != nil{
//You can probaly populate this picker with the keys in
// baseCurrency.baseCur.baseS
Picker("rates", selection: $vm.selectedBaseCurrency){
ForEach((vm.results!.baseCurrencies.first?.value.sorted{$0.key < $1.key})!, id: \.key) { key, rate in
Text(key).tag(key)
}
}
}else{
Text("waiting...")
}
}
}
class CurrencyViewModel: ObservableObject{
@Published var results: BaseCurrency?
@Published var selectedBaseCurrency: String = "usd"{
didSet{
UpdateRates()
}
}
init() {
//If you can .onAppear you don't need it here
//UpdateRates()
}
func UpdateRates() {
print(#function)
let baseUrl = "https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api@1/latest/currencies/"
let baseCur = selectedBaseCurrency // usd
let requestType = ".json"
guard let url = URL(string: baseUrl + baseCur + requestType) else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
do{
let decodedResponse = try JSONDecoder().decode(BaseCurrency.self, from: data)
DispatchQueue.main.async {
if self.results == nil{
//Assign a new base currency
self.results = decodedResponse
}else{ //merge the existing with the new result
for base in decodedResponse.baseCurrencies.keys{
self.results?.baseCurrencies[base] = decodedResponse.baseCurrencies[base]
}
}
//update the UI
self.objectWillChange.send()
}
}catch{
//Error thrown by a try
print(error)//much more informative than error?.localizedDescription
}
}
if error != nil{
//data task error
print(error!)
}
}.resume()
}
}
struct CurrencyView_Previews: PreviewProvider {
static var previews: some View {
CurrencyView()
}
}