Calling a new view in a function SwiftUI - swiftui

I am currently using an api to grab the definitions for a specific word that the user has entered, and the api returns multiple definitions. I want the user to be able to choose what exact definition they want to pair a word with. Since I am interacting with an api, it is in a function and I cannot return anything out of it. I want to grab all the definitions and then show a new view where the user can pick the appropriate definition. How can I go about doing this? I've thought of making an ObservableObject that just has an array as a work around, but that seems a bit excessive. I am new to SwiftUI, so I am unsure whether or not this would be possible. However, I think it would not be because I am not trying to return a view anywhere or using any of the built in things that accepts views.
EDIT: I made SaveArray an ObservableObject and now my problem is that the object is not being updated by my getDef function call. Within the function it is but it is not editing the actual class or at least that is what it is looking like, because on my next view I have a foreach going through the array and nothing is displayed because it is empty. I am not sure whether that is because the sheet is being brought up before the getDef function is done executing.
struct AddWord: View {
#ObservedObject var book: Book
#ObservedObject var currentArray = SaveArray()
#State var addingDefinition = false
#State var word = ""
#State var definition = ""
#State var allDefinitions: [String] = []
#Environment(\.presentationMode) var presentationMode
var body: some View {
NavigationView {
Form {
TextField("Word: ", text: $word)
}
.navigationBarTitle("Add word")
.navigationBarItems(trailing: Button("Add") {
if self.word != "" {
book.words.append(self.word)
getDef(self.word, book, currentArray)
addingDefinition = true
self.presentationMode.wrappedValue.dismiss()
}
}).sheet(isPresented: $addingDefinition) {
PickDefinition(definitions: currentArray, book: book, word: self.word)
}
}
}
func getDef(_ word: String, _ book: Book, _ definitionsArray: SaveArray) {
let request = NSMutableURLRequest(url: NSURL(string: "https://wordsapiv1.p.rapidapi.com/words/\(word)")! as URL,
cachePolicy: .useProtocolCachePolicy,
timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers
let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
if (error != nil) {
print(error)
} else {
do {
let dictionary = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? [String:Any]
//getting the dictionary
let dict = dictionary?["results"] as? [Any]
definitionsArray.currentArray = createArray((dict!))
}
catch {
print("Error parsing")
}
}
})
dataTask.resume()
}
func createArray(_ array: [Any]) -> [String] {
//Get all the definitions given from the api and put it into a string array so you can display it for user to select the correct definiton for their context
var definitions = [String]()
for object in array {
let dictDef = object as? [String: Any]
definitions.append(dictDef?["definition"] as! String)
}
return definitions
}
}
struct AddWord_Previews: PreviewProvider {
static var previews: some View {
AddWord(book: Book())
}
}
struct PickDefinition: View {
#ObservedObject var definitions: SaveArray
var book: Book
var word: String
#Environment(\.presentationMode) var presentationMode
var body: some View {
NavigationView {
VStack {
ForEach(0 ..< definitions.currentArray.count) { index in
Button("\(self.definitions.currentArray[index])", action: {
print("hello")
DB_Manager().addWords(name: self.book.name, word: self.word, definition: self.definitions.currentArray[index])
book.definitions.append(self.definitions.currentArray[index])
self.presentationMode.wrappedValue.dismiss()
})
}
}
.navigationTitle("Choose")
}
}
}
struct PickDefinition_Previews: PreviewProvider {
static var previews: some View {
PickDefinition(definitions: SaveArray(), book: Book(), word: "")
}
}

If you can post more of your code, I can provide a fully working example (e.g. the sample JSON and the views/classes you have built). But for now, I am working with what you provided. I hope the below will help you see just how ObservableObject works.
#Published var dict = [String]() //If the api returns a list of strings, you can make this of type string - I do not have a sample of the JSON so I cannot be sure. If you can provide a sample of the JSON I can better define the way this should work.
var body: some View {
let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
if (error != nil) {
print(error)
} else {
do {
let dictionary = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? [String:Any]
//getting the dictionary
dict = dictionary?["results"] as? [Any] //note that here we are assigning the results of the api call to the Published variable, which our StateObject variable in ContentView is listening to!
var allDef = createArray((dict!))
//No longer need to pass this data forward (as you have below) since we are publishing the information!
//Pass the array to the new view where the user will select the one they want
PickDefinition(definitions: allDef, book: self.book, word: self.word)
}
catch {
print("Error parsing")
}
}
})
dataTask.resume()
}
}
struct ContentView: View {
//StateObject receives updates sent by the Published variable
#StateObject var dictArray = Api()
var body: some View {
NavigationView {
List {
ForEach(dictArray.dict.indices, id: \.self) { index in
Text(dictArray.dict[index])
}
}
}
}
}

Related

Cant view the list of devices

I have a json-result that I get from my own "api". In this I have a list of different devices, that I like to view in a list.
When I add the ForEach, then I get the following error:
Generic struct 'List' requires that 'some AccessibilityRotorContent' conform to 'View'
The JsonResponse:
[{"name":"Tormek-T8","topHorizontal":55,"topVertical":55,"frontHorizontal":44,"frontVertical":44},{"name":"SH-332","topHorizontal":77,"topVertical":77,"frontHorizontal":88,"frontVertical":88}]
Can it be, that there are numbers in this JSON-String and not all is a String?
In my very simple code I had made a struct for the single Device and try to pull it from the url. Why I would get this error? Because the response of the JSON is not nil.
struct Device: Hashable, Codable {
let name: String
let topHorizontal: Double
let topVertical: Double
let frontHorizontal: Double
let frontVertical: Double
}
class ViewModel: ObservableObject {
#Published var devices: [Device] = []
func fetch() {
guard let url = URL(string: "https://cdn.rowoco.de/grindcalculator/devices") else {
return
}
let task = URLSession.shared.dataTask(with: url) { [weak self] data, _, error in
guard let data = data, error == nil else {
return
}
do {
let devices = try JSONDecoder().decode([Device].self, from: data)
DispatchQueue.main.async {
self?.devices = devices
}
} catch {
print(error)
}
}
task.resume()
}
}
struct CdnDevicesListView: View {
#Environment(\.presentationMode) var presentationMode
#StateObject var viewModel = ViewModel()
var body: some View {
NavigationView {
List {
ForEach(viewModel.devices, id: \.self) { device in
device.name
}
}
.navigationTitle("cdn devices")
.onAppear {
viewModel.fetch()
}
}
}
}
ForEach's content needs to be a View.
device.name is not a View.

Global variable

Is there any way I can make it so I can use the variable "bggg"? Im trying to make a api call and then use the data to change the view but I cannot figure out how to access the variables. Its saying that it cannot find bggg in its scope.
public struct RootView: View {
public init() {Task {
let (data, _) = try await URLSession.shared.data(from: URL(string:"https://api.openweathermap.org/data/2.5/onecall?lat=32&lon=-94&units=imperial&exclude=minutely,hourly,daily&appid=bf1daa8bf4997bc299d459c8db985f8f")!)
let decodedResponse = try JSONDecoder().decode(WeatherResponse.self, from: data)
var bggg = decodedResponse.current.weather.description
}}
var body: some View {
Text("\(bggg)")
Color.red
}
}
You can use Combine: set a publisher which means a property that sends data, then set another property as subscriber(this property will listen to the publisher) if any changes will happen immediately the subscriber will be notified
1. Set the publisher
class DownloadWithCombineViewModel: ObservableObject {
#Published var bggg: String = ""
public init() {Task {
let (data, _) = try await URLSession.shared.data(from: URL(string:"https://api.openweathermap.org/data/2.5/onecall?lat=32&lon=-94&units=imperial&exclude=minutely,hourly,daily&appid=bf1daa8bf4997bc299d459c8db985f8f")!)
let decodedResponse = try JSONDecoder().decode(WeatherResponse.self, from: data)
var bggg = decodedResponse.current.weather.description
}
}
2. set the subscriber (ObservedObject)
struct ContentView: View {
#ObservedObject var value = DownloadWithCombineViewModel()
var body: some View {
Text("\(value.bggg)")
Color.red
}
}
SwiftUI view state is managed by various property wrappers: #State, #StateObject, #Binding, #EnvironmentObject, etc. These will be covered in most SwiftUI tutorials, but in this case if you want to keep the State local to the View, you might implement it like this:
public struct RootView : View {
#State private var bggg: String = "Loading…"
public var body: some View {
Text("\(bggg)")
.task {
do {
let (data, _) = try await URLSession.shared.data(from: URL(string:"https://api.openweathermap.org/data/2.5/onecall?lat=32&lon=-94&units=imperial&exclude=minutely,hourly,daily&appid=bf1daa8bf4997bc299d459c8db985f8f")!)
let decodedResponse = try JSONDecoder().decode(WeatherResponse.self, from: data)
self.bggg = decodedResponse.current.weather.description
} catch {
self.bggg = "Error: \(error)"
}
}
}
}

How to fetch Google Places data in SwiftUI?

I'm new to SwiftUI. Currently struggling with fetching and presenting photos and places names to my List from Google Places (Maps) API. I do know that they provide explanation of how to do it, but since I'm not that experienced yet, i cannot get the code provided just for Swift (not Swift UI). Tried to use the method below:
struct Response: Codable {
var results: [Place]
}
struct Place: Codable {
var placeId: Int
var placeName: String
var placePic: String
var placeTime: String
var placePhone: String
var placeLocation: String
}
#State var results = [Place] ()
var body: some View {
List(results, id: \.placeId) { item in
VStack{
Text(item.placeName)
}
}.onAppear(perform: loadData)
}
func loadData(){
guard let url = URL(string: "https://maps.googleapis.com/maps/api/place/photo?parameters") else{
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request){data, responce, error in
if let data = data {
if let decodedResponse = try? JSONDecoder().decode(Response.self, from: data) {
DispatchQueue.main.async {
self.results = decodedResponse.results
}
return
}
}
print("fetch failed: \(error?.localizedDescription ?? "Unknown error")")
}.resume()
}
}
Question:
Is there any ideas of what i do wrong? Because I tried to search for some tutorials on the web, using SwiftUI, but haven't found any.

Why doesn't this SwiftUI View update when changing a #State variable?

I've got a SwiftUI View that takes a Hacker News API submission ID, and then fetches the details for that item in fetchStory().
When fetchStory() completed its HTTP call, it updates the #State private var url on the View, however the View never re-renders to show the new value -- it always shows the initial empty value.
Why?
import Foundation
import SwiftUI
struct StoryItem: Decodable {
let title: String
let url: String?
}
struct StoryView: View {
public var _storyId: Int
#State private var url: String = "";
init(storyId: Int) {
self._storyId = storyId
self.fetchStory()
}
var body: some View {
VStack {
Text("(Load a webview here for the URL of Story #\(self._storyId))")
Text("URL is: \(self.url)") // this never changes!
}
}
private func fetchStory() {
let url = URL(string: "https://hacker-news.firebaseio.com/v0/item/\(self._storyId).json")!
let task = URLSession.shared.dataTask(with: url) {(data, response, error) in
guard let data = data else {
print(String(error.debugDescription))
return
}
do {
let item: StoryItem = try JSONDecoder().decode(StoryItem.self, from: data)
if let storyUrl = item.url {
self.url = storyUrl
} else {
print("No url")
}
} catch {
print(error)
}
}
task.resume()
}
}
struct StoryView_Previews: PreviewProvider {
static var previews: some View {
StoryView(storyId: 22862053)
}
}
something like this:
import SwiftUI
struct StoryItem: Decodable {
let title: String
let url: String?
}
class ObservedStoryId: ObservableObject {
#Published var storyId: String = ""
init(storyId: String) {
self.storyId = storyId
}
}
struct StoryView: View {
#ObservedObject var storyId: ObservedStoryId
#State var url: String = ""
var body: some View {
VStack {
Text("(Load a webview here for the URL of Story #\(self.storyId.storyId))")
Text("URL is: \(self.url)")
Text(self.storyId.storyId)
}.onReceive(storyId.$storyId) { _ in self.fetchStory() }
}
private func fetchStory() {
let url = URL(string: "https://hacker-news.firebaseio.com/v0/item/\(self.storyId.storyId).json")!
let task = URLSession.shared.dataTask(with: url) {(data, response, error) in
guard let data = data else {
print(String(error.debugDescription))
return
}
do {
let item: StoryItem = try JSONDecoder().decode(StoryItem.self, from: data)
if let storyUrl = item.url {
self.url = storyUrl
} else {
print("No url")
}
} catch {
print(error)
}
}
task.resume()
}
}
and call it like this:
struct ContentView: View {
#ObservedObject var storyId = ObservedStoryId(storyId: "22862053")
var body: some View {
StoryView(storyId: storyId)
}
}
to fix your problem:
init(storyId: Int) {
self._storyId = storyId
}
var body: some View {
VStack {
Text("(Load a webview here for the URL of Story #\(self._storyId))")
Text("URL is: \(self.url)") // this now works
}.onAppear(perform: fetchStory)
}
why does this works and not your code,
my guess is this: "self.url" can only be updated/changed within the special SwiftUI View functions, such as onAppear(), elsewhere it does not change a thing.

Simplest way to pass #Published data to a Textfield()?

Scenario:
I'm using an Observable Class to acquire data from the network.
In this case some elementary weather data.
Problem:
I don't know how to display this data in the calling View.
For the time-being, I merely am trying to populate a Textfield (and worry about more-eleborate layout later).
I get the following:
.../StandardWeatherView.swift:22:13: Cannot invoke initializer for
type 'TextField<_>' with an argument list of type '(Text, text:
Sample?)'
Here's is my calling View which is the receiver of #ObservedObject data:
import SwiftUI
struct StandardWeatherView: View {
#EnvironmentObject var settings: Settings
#ObservedObject var standardWeatherReportLoader = StandardWeatherReportLoader()
init() {
self.standardWeatherReportLoader.doStandard()
}
var body: some View {
ZStack {
Color("FernGreen").edgesIgnoringSafeArea(.all)
TextField(Text("Weather Data"), text: standardWeatherReportLoader.weatherReport)
}
}
}
struct StandardWeatherView_Previews: PreviewProvider {
static var previews: some View {
StandardWeatherView()
}
}
Here's the publisher, acquiring data:
import Foundation
class StandardWeatherReportLoader: ObservableObject {
#Published var networkMessage: String?
#Published var hasAlert = false
#Published var weatherReport: Sample?
#Published var hasReport = false
func doStandard() {
let url = EndPoint.weather.path()
var request = URLRequest(url: EndPoint.weather.path()!)
request.httpMethod = "GET"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
let task = URLSession.shared.dataTask(with: url!) { (data: Data?, _: URLResponse?, error: Error?) -> Void in
DispatchQueue.main.async {
guard error == nil else {
self.networkMessage = error?.localizedDescription
self.hasAlert = true
return
}
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let result = try decoder.decode(Sample.self, from: data!)
self.weatherReport = result
self.hasReport = true
print("\n Standard Weather ----------------")
print(#function, "line: ", #line, "Result: ",result)
print("\n")
} catch let error as NSError {
print(error)
}
}
}
task.resume()
}
}
What's the simplest way of passing a string of data to the View via #Published var?
Log:
Standard Weather ---------------- doStandard() line: 38 Result:
Sample(coord: DataTaskPubTab.Coord(lon: -0.13, lat: 51.51), weather:
[DataTaskPubTab.Weather(id: 300, main: "Drizzle", description: "light
intensity drizzle")], base: "stations", main:
DataTaskPubTab.Main(temp: 280.32, pressure: 1012, humidity: 81,
tempMin: 279.15, tempMax: 281.15), visibility: 10000, wind:
DataTaskPubTab.Wind(speed: 4.1, deg: 80), clouds:
DataTaskPubTab.Clouds(all: 90), dt: 1485789600.0, id: 2643743, name:
"London")
But I'm getting nil at the TextField:
(lldb) po standardWeatherReportLoader.weatherReport nil
One option is to set a binding within your body to track whenever the TextField has updated. From within this binding, you can then edit your Published variable as you wish:
#ObservedObject var reportLoader = StandardWeatherReportLoader()
var body: some View {
// Binding to detect when TextField changes
let textBinding = Binding<String>(get: {
self.reportLoader.networkMessage
}, set: {
self.reportLoader.networkMessage = $0
})
// Return view containing the text field
return VStack {
TextField("Enter the Network Message", text: textBinding)
}
}
Edit: Also in your original post, you were passing an object of optional type Sample into the TextField which was expecting a binding String type which could cause some issues.