[fix] LCENavigationView: remove phantom glass button, center title safely

Dummy mirrored button used to balance title centering rendered as a
visible empty glass pill under iOS 26's automatic button chrome. Side
buttons now only render when actually configured, title centers via
ZStack independent of button widths, and title padding is derived from
measured button width so long titles truncate instead of overlapping.
Glass button style is opt-in via setGlassButtonsEnabled(_:), off by
default.

Sources/LCEssentials/SwiftUI/LCENavigationView.swift

@@ -49,6 +49,39 @@ class LCENavigationState: ObservableObject {
     @Published var subTitle: (any View) = Text("")
     /// The background color of the navigation bar.
     @Published var navigationBarBackgroundColor: Color = .clear
+
+    /// Whether a left button was actually configured via `setLeftButton`.
+    @Published var hasLeftButton: Bool = false
+    /// Whether a right button was actually configured via `setRightButton`.
+    @Published var hasRightButton: Bool = false
+    /// Whether buttons should opt into the system Liquid Glass button style (iOS 26+). Off by default.
+    @Published var useGlassButtons: Bool = false
+}
+
+/// `PreferenceKey` used to measure the widest side button so the title can be padded symmetrically and stay centered without overlapping either button.
+@available(iOS 15, *)
+private struct LCENavButtonWidthPreferenceKey: PreferenceKey {
+    static var defaultValue: CGFloat { 0 }
+    static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) {
+        value = max(value, nextValue())
+    }
+}
+
+@available(iOS 15, *)
+private extension View {
+    /// Applies `.glass` button style on iOS 26+ when enabled, otherwise falls back to `.plain` — the navigation bar is not designed around glass, but stays opt-in ready.
+    @ViewBuilder
+    func lce_applyGlassIfEnabled(_ enabled: Bool) -> some View {
+        if enabled {
+            if #available(iOS 26.0, *) {
+                self.buttonStyle(.glass)
+            } else {
+                self.buttonStyle(.plain)
+            }
+        } else {
+            self.buttonStyle(.plain)
+        }
+    }
 }
 
 /// `LCENavigationView` is a SwiftUI `View` that provides a customizable navigation bar.
@@ -61,6 +94,9 @@ public struct LCENavigationView<Content: View>: View {
     /// The content view displayed below the navigation bar.
     let content: Content
 
+    /// The measured width of the widest side button, used to pad the title so it never overlaps either button.
+    @State private var maxButtonWidth: CGFloat = 0
+
     /// Initializes a new `LCENavigationView` instance.
     /// - Parameters:
     ///   - title: The title view for the navigation bar. Defaults to an empty `Text`.
@@ -92,18 +128,29 @@ public struct LCENavigationView<Content: View>: View {
 
     /// The private `NavigationBarView` that lays out the navigation bar components.
     private var NavigationBarView: some View {
-        HStack {
+        ZStack {
-            NavLeftButton
-            Spacer()
             TitleView
-            Spacer()
+                .padding(.horizontal, maxButtonWidth)
-            NavRightButton
+                .lineLimit(1)
+                .minimumScaleFactor(0.7)
+                .frame(maxWidth: .infinity)
+
+            HStack {
+                if state.hasLeftButton {
+                    NavLeftButton
+                }
+                Spacer()
+                if state.hasRightButton {
+                    NavRightButton
+                }
+            }
         }
         .font(.headline)
         .padding()
         .background {
             state.navigationBarBackgroundColor.ignoresSafeArea(edges: .top)
         }
+        .onPreferenceChange(LCENavButtonWidthPreferenceKey.self) { maxButtonWidth = $0 }
     }
 
     /// The private `TitleView` that displays the title and subtitle.
@@ -116,7 +163,7 @@ public struct LCENavigationView<Content: View>: View {
         }
     }
 
-    /// The private `NavLeftButton` view.
+    /// The private `NavLeftButton` view. Only rendered when `setLeftButton` was actually called — never a hidden placeholder.
     private var NavLeftButton: some View {
         Button(action: state.leftButtonAction) {
             HStack {
@@ -126,9 +173,15 @@ public struct LCENavigationView<Content: View>: View {
                 state.leftButtonText
             }
         }
+        .lce_applyGlassIfEnabled(state.useGlassButtons)
+        .background(
+            GeometryReader { proxy in
+                Color.clear.preference(key: LCENavButtonWidthPreferenceKey.self, value: proxy.size.width)
+            }
+        )
     }
 
-    /// The private `NavRightButton` view.
+    /// The private `NavRightButton` view. Only rendered when `setRightButton` was actually called — never a hidden placeholder.
     private var NavRightButton: some View {
         Button(action: state.rightButtonAction) {
             HStack {
@@ -138,6 +191,12 @@ public struct LCENavigationView<Content: View>: View {
                 }
             }
         }
+        .lce_applyGlassIfEnabled(state.useGlassButtons)
+        .background(
+            GeometryReader { proxy in
+                Color.clear.preference(key: LCENavButtonWidthPreferenceKey.self, value: proxy.size.width)
+            }
+        )
     }
     
     /// Sets the configuration for the right button of the navigation bar.
@@ -158,13 +217,7 @@ public struct LCENavigationView<Content: View>: View {
         }
         state.rightButtonText = text
         state.rightButtonAction = action
-        
+        state.hasRightButton = true
-        if let string = state.leftButtonText.string, string.isEmpty {
-            state.leftButtonText = text.foregroundColor(.clear)
-        }
-        if state.leftButtonImage == nil {
-            state.leftButtonImage = image?.foregroundColor(.clear) as? AnyView
-        }
 
         return self
     }
@@ -187,14 +240,17 @@ public struct LCENavigationView<Content: View>: View {
         }
         state.leftButtonText = text
         state.leftButtonAction = action
+        state.hasLeftButton = true
 
-        if let string = state.rightButtonText.string, string.isEmpty {
+        return self
-            state.rightButtonText = text.foregroundColor(.clear)
+    }
-        }
-        if state.rightButtonImage == nil {
-            state.rightButtonImage = image?.foregroundColor(.clear) as? AnyView
-        }
 
+    /// Opts the navigation bar's buttons into the system Liquid Glass `.glass` button style on iOS 26+.
+    /// The navigation bar is designed as a plain, non-glass component by default; call this to enable glass explicitly.
+    /// - Parameter enabled: Whether buttons should use the glass style.
+    /// - Returns: The `LCENavigationView` instance for chaining.
+    public func setGlassButtonsEnabled(_ enabled: Bool) -> LCENavigationView {
+        state.useGlassButtons = enabled
         return self
     }
     
@@ -229,101 +285,6 @@ public struct LCENavigationView<Content: View>: View {
     }
 }
 
-/// Extension to `FormatStyle` to format any value as a string.
-@available(iOS 15.0, *)
-extension FormatStyle {
-    /// Formats an input value if it matches the `FormatInput` type.
-    /// - Parameter value: The value to format as `Any`.
-    /// - Returns: The formatted output, or `nil` if the value type does not match.
-    func format(any value: Any) -> FormatOutput? {
-        if let v = value as? FormatInput {
-            return format(v)
-        }
-        return nil
-    }
-}
-
-/// Extension to `LocalizedStringKey` to resolve localized strings.
-@available(iOS 15.0, *)
-extension LocalizedStringKey {
-    /// Resolves the localized string key into a `String`.
-    /// - Returns: The resolved string, or `nil` if resolution fails.
-    var resolved: String? {
-        let mirror = Mirror(reflecting: self)
-        guard let key = mirror.descendant("key") as? String else {
-            return nil
-        }
-
-        guard let args = mirror.descendant("arguments") as? [Any] else {
-            return nil
-        }
-
-        let values = args.map { arg -> Any? in
-            let mirror = Mirror(reflecting: arg)
-            if let value = mirror.descendant("storage", "value", ".0") {
-                return value
-            }
-
-            guard let format = mirror.descendant("storage", "formatStyleValue", "format") as? any FormatStyle,
-                  let input = mirror.descendant("storage", "formatStyleValue", "input") else {
-                return nil
-            }
-
-            return format.format(any: input)
-        }
-
-        let va = values.compactMap { arg -> CVarArg? in
-            switch arg {
-            case let i as Int:      return i
-            case let i as Int64:    return i
-            case let i as Int8:     return i
-            case let i as Int16:    return i
-            case let i as Int32:    return i
-            case let u as UInt:     return u
-            case let u as UInt64:   return u
-            case let u as UInt8:    return u
-            case let u as UInt16:   return u
-            case let u as UInt32:   return u
-            case let f as Float:    return f
-            case let f as CGFloat:  return f
-            case let d as Double:   return d
-            case let o as NSObject: return o
-            default:                return nil
-            }
-        }
-
-        if va.count != values.count {
-            return nil
-        }
-
-        return String.localizedStringWithFormat(key, va)
-    }
-}
-
-/// Extension to `Text` to retrieve its string content.
-@available(iOS 15.0, *)
-extension Text {
-    /// Returns the string representation of the `Text` view.
-    /// - Returns: The string content, or `nil` if it cannot be extracted.
-    var string: String? {
-        let mirror = Mirror(reflecting: self)
-        if let s = mirror.descendant("storage", "verbatim") as? String {
-            return s
-        } else if let attrStr = mirror.descendant("storage", "anyTextStorage", "str") as? AttributedString {
-            return String(attrStr.characters)
-        } else if let key = mirror.descendant("storage", "anyTextStorage", "key") as? LocalizedStringKey {
-            return key.resolved
-        } else if let format = mirror.descendant("storage", "anyTextStorage", "storage", "format") as? any FormatStyle,
-                  let input = mirror.descendant("storage", "anyTextStorage", "storage", "input") {
-            return format.format(any: input) as? String
-        } else if let formatter = mirror.descendant("storage", "anyTextStorage", "formatter") as? Formatter,
-                  let object = mirror.descendant("storage", "anyTextStorage", "object") {
-            return formatter.string(for: object)
-        }
-        return nil
-    }
-}
-
 //@available(iOS 15.0, *)
 //struct LCENavigationView_Previews: PreviewProvider {
 //    static var previews: some View {