對于視障人士的應用程式，我想在視圖中顯示 POI。我使用下面的代碼。盡管最低級別 ( requestNearbyLocations) 將資訊列印到除錯螢屏，但我無法將此資料 ( locdata) 回傳到呼叫方法，因此也無法回傳到視圖。
所用代碼的主要摘錄：
struct ContentView: View {
var Apple: AppleData = AppleData()
var body: some View {
Text(Apple.text)
.onAppear {
Apple.requestLoc()
}
}
}
和
class AppleData {
var text = ""
func requestLoc() -> Void {
Task {
async let mytext = requestNearbyLocations()
text = await mytext
}
}
func requestNearbyLocations() async -> String {
var region = MKCoordinateRegion()
region.center = CLLocationCoordinate2D(latitude: 52.060049, longitude: 4.542196)
var loctext = ""
let request = MKLocalPointsOfInterestRequest(center: region.center, radius: 100.0)
request.pointOfInterestFilter = MKPointOfInterestFilter(excluding: [.restaurant, .cafe])
let search = MKLocalSearch(request: request)
do {
let response = try await search.start()
print(response.mapItems)
for item in response.mapItems {
print( item.name! )
loctext = item.name!
}
}
catch {
print(error)
}
return loctext
}
}
我在這里錯過了什么？
uj5u.com熱心網友回復：
您想“觀察” text.
因此，宣告AppleData為 anObservableObject和textto be @Published：
class AppleData: ObservableObject {
@Published var text = ""
...
}
并且ContentView應該將該物件指定為@ObservedObject：
struct ContentView: View {
@ObservedObject var apple = AppleData()
var body: some View {
Text(apple.text)
.onAppear {
apple.requestLoc()
}
}
}
請參閱在您的應用程式中管理模型資料。
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