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StateObject that works in iOS 13
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import Combine | |
import PublishedObject // https://github.com/Amzd/PublishedObject | |
import SwiftUI | |
/// A property wrapper type that instantiates an observable object. | |
@propertyWrapper | |
public struct StateObject<ObjectType: ObservableObject>: DynamicProperty | |
where ObjectType.ObjectWillChangePublisher == ObservableObjectPublisher { | |
/// Wrapper that helps with initialising without actually having an ObservableObject yet | |
private class ObservedObjectWrapper: ObservableObject { | |
@PublishedObject var wrappedObject: ObjectType? = nil | |
init() {} | |
} | |
private var thunk: () -> ObjectType | |
@ObservedObject private var observedObject = ObservedObjectWrapper() | |
@State private var state = ObservedObjectWrapper() | |
public var wrappedValue: ObjectType { | |
if state.wrappedObject == nil { | |
// There is no State yet so we need to initialise the object | |
state.wrappedObject = thunk() | |
// and start observing it | |
observedObject.wrappedObject = state.wrappedObject | |
} else if observedObject.wrappedObject == nil { | |
// Retrieve the object from State and observe it in ObservedObject | |
observedObject.wrappedObject = state.wrappedObject | |
} | |
return state.wrappedObject! | |
} | |
public var projectedValue: ObservedObject<ObjectType>.Wrapper { | |
ObservedObject(wrappedValue: wrappedValue).projectedValue | |
} | |
public init(wrappedValue thunk: @autoclosure @escaping () -> ObjectType) { | |
self.thunk = thunk | |
} | |
public mutating func update() { | |
// Not sure what this does but we'll just forward it | |
_state.update() | |
_observedObject.update() | |
} | |
} |
[Is there a way to conditionally use @StateObject while targeting iOS 13 but use apple's @StateObject in iOS 14
If you are using Combine's ObservableObject as the @StateObject you could use Async/await to replace the functionality and that is backwards compatible with iOS 13. Could be tricky without the task(priority:_:)
modifier though.
[Is there a way to conditionally use @StateObject while targeting iOS 13 but use apple's @StateObject in iOS 14
try this?
@available(iOS 13, obsoleted: 14)
@available(iOS 13, obsoleted: 14)
@calvingit this not work
I insert a break point, it also called iOS 13 method...
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