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)"
}
}
}
}
Related
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.
See my code below. My problem is if i change accessToken via UserService.shared.currentStore.accessToken = xxx, SwiftUI doesn't publish, and there's no update on StoreBanner at all.
//SceneDelegate
let contentView = ContentView()
.environmentObject(UserService.shared)
//Define
class UserService: ObservableObject {
#Published var currentStore = Store.defaultValues()
static let shared = UserService()
}
struct Store: Codable, Hashable {
var storeName: String = ""
var accessToken: String = ""
}
//Use it
struct StoreBanner: View {
var body: some View {
Group {
if UserService.shared.currentStore.accessToken.isNotEmpty {
ShopifyLinkedBanner()
} else {
ShopifyLinkBanner()
}
}
}
}
You're trying to use UserService inside StoreBanner without using a property wrapper to tell the view to respond to updates. Without the #ObservedObject property wrapper, the View doesn't have a mechanism to know that any of the #Published properties have been updated.
Try this:
struct StoreBanner: View {
#ObservedObject private var userService = UserService.shared
var body: some View {
Group {
if userService.currentStore.accessToken.isNotEmpty {
ShopifyLinkedBanner()
} else {
ShopifyLinkBanner()
}
}
}
}
This should work assuming you set accessToken somewhere in your code on the same instance of UserService.
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])
}
}
}
}
}
I am trying a very simple test to just combine a simple Just("JustValue") to a property.
But it did not work.
↓ This is my code
struct ResponseView: View {
private var contentCancellable: AnyCancellable? = nil
#State var content: String = "InitialValue"
var body: some View {
Text(content)
}
init() {
contentCancellable = Just("JustValue").assign(to: \.content, on: self)
}
}
Is there anyone know why the Text shows "InitialValue" instead "JustValue"
This is specific of state property wrapper initialization pass... the external state storage is created later so only one initialisation is applied.
If you want to update it, do it later, when state be already created and linked to view, like
struct ResponseView: View {
#State var content: String = "InitialValue"
var body: some View {
Text(content)
.onAppear {
_ = Just("JustValue").assign(to: \.content, on: self)
}
}
}
the gives UI which you expected.
I want a #Published variable to be persisted, so that it's the same every time when I relaunch my app.
I want to use both the #UserDefault and #Published property wrappers on one variable. For example I need a '#PublishedUserDefault var isLogedIn'.
I have the following propertyWrapper
import Foundation
#propertyWrapper
struct UserDefault<T> {
let key: String
let defaultValue: T
init(_ key: String, defaultValue: T) {
self.key = key
self.defaultValue = defaultValue
}
var wrappedValue: T {
get {
return UserDefaults.standard.object(forKey: key) as? T ?? defaultValue
}
set {
UserDefaults.standard.set(newValue, forKey: key)
}
}
}
This is my Settings class
import SwiftUI
import Combine
class Settings: ObservableObject {
#Published var isLogedIn : Bool = false
func doLogin(params:[String:String]) {
Webservice().login(params: params) { response in
if let myresponse = response {
self.login = myresponse.login
}
}
}
}
My View class
struct HomeView : View {
#EnvironmentObject var settings: Settings
var body: some View {
VStack {
if settings.isLogedIn {
Text("Loged in")
} else{
Text("Not Loged in")
}
}
}
}
Is there a way to make a single property wrapper that covers both the persisting and the publishing?
import SwiftUI
import Combine
fileprivate var cancellables = [String : AnyCancellable] ()
public extension Published {
init(wrappedValue defaultValue: Value, key: String) {
let value = UserDefaults.standard.object(forKey: key) as? Value ?? defaultValue
self.init(initialValue: value)
cancellables[key] = projectedValue.sink { val in
UserDefaults.standard.set(val, forKey: key)
}
}
}
class Settings: ObservableObject {
#Published(key: "isLogedIn") var isLogedIn = false
...
}
Sample: https://youtu.be/TXdAg_YvBNE
Version for all Codable types check out here
To persist your data you could use the #AppStorage property wrapper.
However, without using #Published your ObservableObject will no longer put out the news about the changed data. To fix this, simply call objectWillChange.send() from the property's willSet observer.
import SwiftUI
class Settings: ObservableObject {
#AppStorage("Example") var example: Bool = false {
willSet {
// Call objectWillChange manually since #AppStorage is not published
objectWillChange.send()
}
}
}
It should be possible to compose a new property wrapper:
Composition was left out of the first revision of this proposal,
because one can manually compose property wrapper types. For example,
the composition #A #B could be implemented as an AB wrapper:
#propertyWrapper
struct AB<Value> {
private var storage: A<B<Value>>
var wrappedValue: Value {
get { storage.wrappedValue.wrappedValue }
set { storage.wrappedValue.wrappedValue = newValue }
}
}
The main benefit of this approach is its predictability: the author of
AB decides how to best achieve the composition of A and B, names it
appropriately, and provides the right API and documentation of its
semantics. On the other hand, having to manually write out each of the
compositions is a lot of boilerplate, particularly for a feature whose
main selling point is the elimination of boilerplate. It is also
unfortunate to have to invent names for each composition---when I try
the compose A and B via #A #B, how do I know to go look for the
manually-composed property wrapper type AB? Or maybe that should be
BA?
Ref: Property WrappersProposal: SE-0258
You currently can't wrap #UserDefault around #Published since that is not currently allowed.
The way to implement #PublishedUserDefault is to pass an objectWillChange into the wrapper and call it before setting the variable.
struct HomeView : View {
#StateObject var auth = Auth()
#AppStorage("username") var username: String = "Anonymous"
var body: some View {
VStack {
if username != "Anonymous" {
Text("Logged in")
} else{
Text("Not Logged in")
}
}
.onAppear(){
auth.login()
}
}
}
import SwiftUI
import Combine
class Auth: ObservableObject {
func login(params:[String:String]) {
Webservice().login(params: params) { response in
if let myresponse = response {
UserDefaults.standard.set(myresponse.login, forKey: "username")`
}
}
}
}