Add support for AdwBanner

Documentation/Reference/README.md

@@ -17,6 +17,7 @@
 
 -   [AboutWindow](structs/AboutWindow.md)
 -   [AppearObserver](structs/AppearObserver.md)
+-   [Banner](structs/Banner.md)
 -   [Binding](structs/Binding.md)
 -   [Button](structs/Button.md)
 -   [Carousel](structs/Carousel.md)

Documentation/Reference/structs/Banner.md

@@ -0,0 +1,55 @@
+**STRUCT**
+
+# `Banner`
+
+A banner widget.
+
+## Properties
+### `title`
+
+The content.
+
+### `visible`
+
+Whether the banner is visible.
+
+### `buttonLabel`
+
+The button's label.
+
+### `handler`
+
+The button's handler.
+
+## Methods
+### `init(_:visible:)`
+
+Initialize a text widget.
+- Parameters:
+    - title: The content.
+    - visible: Whether the banner is visible.
+
+### `update(_:modifiers:)`
+
+Update the view storage of the text widget.
+- Parameters:
+    - storage: The view storage.
+    - modifiers: Modify views before being updated.
+
+### `container(modifiers:)`
+
+Get the container of the text widget.
+- Returns: The view storage.
+
+### `update(banner:)`
+
+Update the banner.
+- Parameter banner: The banner.
+
+### `button(_:handler:)`
+
+Configure the banner's button.
+- Parameters:
+    - label: The button's title.
+    - handler: The button's handler.
+- Returns: The banner.

Sources/Adwaita/View/Banner.swift

@@ -0,0 +1,76 @@
+//
+//  Banner.swift
+//  Adwaita
+//
+//  Created by david-swift on 03.01.24.
+//
+
+import Libadwaita
+
+/// A banner widget.
+public struct Banner: Widget {
+
+    /// The content.
+    var title: String
+    /// Whether the banner is visible.
+    var visible: Bool
+    /// The button's label.
+    var buttonLabel: String?
+    /// The button's handler.
+    var handler: () -> Void = { }
+
+    /// Initialize a text widget.
+    /// - Parameters:
+    ///     - title: The content.
+    ///     - visible: Whether the banner is visible.
+    public init(_ title: String, visible: Bool) {
+        self.title = title
+        self.visible = visible
+    }
+
+    /// Update the view storage of the text widget.
+    /// - Parameters:
+    ///     - storage: The view storage.
+    ///     - modifiers: Modify views before being updated.
+    public func update(_ storage: ViewStorage, modifiers: [(View) -> View]) {
+        if let banner = storage.view as? Libadwaita.Banner {
+            update(banner: banner)
+        }
+    }
+
+    /// Get the container of the text widget.
+    /// - Returns: The view storage.
+    public func container(modifiers: [(View) -> View]) -> ViewStorage {
+        let banner = Libadwaita.Banner(title)
+        update(banner: banner)
+        return .init(banner)
+    }
+
+    /// Update the banner.
+    /// - Parameter banner: The banner.
+    func update(banner: Libadwaita.Banner) {
+        _ = banner.title(title)
+        if let buttonLabel {
+            _ = banner.buttonLabel(buttonLabel)
+            _ = banner.buttonHandler(handler)
+        }
+        if visible {
+            banner.show()
+        } else {
+            banner.hide()
+        }
+    }
+
+    /// Configure the banner's button.
+    /// - Parameters:
+    ///     - label: The button's title.
+    ///     - handler: The button's handler.
+    /// - Returns: The banner.
+    public func button(_ label: String, handler: @escaping () -> Void) -> Self {
+        var newSelf = self
+        newSelf.buttonLabel = label
+        newSelf.handler = handler
+        return newSelf
+    }
+
+}

user-manual/Information/Widgets.md

@@ -21,6 +21,7 @@ This is an overview of the available widgets and other components in _Adwaita_.
 | Carousel             | A paginated scrolling widget.                                       | AdwCarousel            |
 | ViewSwitcher         | A control for switching between different views.                    | AdwViewSwitcher        |
 | ProgressBar          | A bar showing a progress.                                           | GtkProgressBar         |
+| Banner               | A bar showing contextual information.                               | AdwBanner              |
 | StateWrapper         | A wrapper not affecting the UI which stores state information.      | -                      |
 
 ### View Modifiers
@@ -76,6 +77,11 @@ This is an overview of the available widgets and other components in _Adwaita_.
 | ---------------------------- | --------------------------------------------------------------------------------------- |
 | `wideDesign(_:)`             | Whether the wide view switcher design is used.                                          |
 
+## `Banner` Modifiers
+| Syntax                       | Description                                                                             |
+| ---------------------------- | --------------------------------------------------------------------------------------- |
+| `button(_:handler)`          | Show the banner's button and set its title and handler.                                 |
+
 ### Window Types
 | Name                 | Description                                                       | Widget                 |
 | -------------------- | ----------------------------------------------------------------- | ---------------------- |