Introduce SwiftMessagesHideAction and Environment Key for SwiftUI

[mofeejegi]

PR description

This PR addresses #549.
It introduces a swiftMessagesHide environment value for SwiftMessages that will allow SwiftUI messages to self-dismiss. This enhancement mirrors Apple’s own @Environment(\.dismiss) pattern, allowing your custom message views to grab a hide() or hide(animated:) closure from the environment and invoke it as needed.

How to Use

In your View, just declare the environment key like this:

@Environment(\.swiftMessagesHide) private var hide

And then call hide() or hide(animated:) to dismiss the swiftUI message.

Demo

Check out the sample demo in SwiftUIDemo/SwiftUIDemo/DemoView.swift.

[wtmoose]

This isn't quite the same thing as the built-in dismiss environment variable, which is an instance of DismissAction. DismissAction's is a struct, which prevents the behavior from being modified or overwritten (not to mention, the initializer isn't public). DismissAction that implements callAsFunction(), allowing the simple invocation dismiss().

How about we make a struct SwiftMessagesHideAction:

1. SwiftMessagesHideAction/callAsFunction() calls SwiftMessages.hide(true)
2. An additional function SwiftMessagesHideAction/hide(_ animated: Bool) can be invoked if animation needs to be specified.

[wtmoose]

Couple of minor change requests. In general, we prioritize APIs at the top of a file and implementation details below—the reader is usually most interested in how to use the code rather than how it was implemented.

[wtmoose]

Suggested change

	/// Dismiss with animation.
	@MainActor
	public func callAsFunction() {
	SwiftMessages.hide(animated: true)
	}
	/// Dismiss, optionally animated.
	@MainActor
	public func callAsFunction(animated: Bool) {
	SwiftMessages.hide(animated: animated)
	}
	/// Dismiss with option to disable animation.
	@MainActor
	public func callAsFunction(animated: Bool = true) {
	SwiftMessages.hide(animated: animated)
	}

[wtmoose]

Suggested change

	// MARK: ––– Environment Key & Value –––
	private struct SwiftMessagesHideKey: EnvironmentKey {
	/// Default to our action struct, which itself defaults to animated.
	static let defaultValue: SwiftMessagesHideAction = SwiftMessagesHideAction()
	}
	public extension EnvironmentValues {
	/// Inject `@Environment(\.swiftMessagesHide)` into your views.
	/// - Use `hide()` for the default animated dismissal.
	/// - Use `hide(false)` to bypass animation.
	var swiftMessagesHide: SwiftMessagesHideAction {
	get { self[SwiftMessagesHideKey.self] }
	set { self[SwiftMessagesHideKey.self] = newValue }
	}
	}
	public extension EnvironmentValues {
	/// Inject `@Environment(\.swiftMessagesHide)` into your views.
	/// - Use `hide()` for the default animated dismissal.
	/// - Use `hide(false)` to bypass animation.
	var swiftMessagesHide: SwiftMessagesHideAction {
	get { self[SwiftMessagesHideKey.self] }
	set { self[SwiftMessagesHideKey.self] = newValue }
	}
	}
	private struct SwiftMessagesHideKey: EnvironmentKey {
	/// Default to our action struct, which itself defaults to animated.
	static let defaultValue: SwiftMessagesHideAction = SwiftMessagesHideAction()
	}