Use preference pane title as window title (#19)

Fixes #15

Example/AdvancedPreferenceViewController.swift

@@ -3,7 +3,7 @@ import Preferences
 
 final class AdvancedPreferenceViewController: NSViewController, PreferencePane {
 	let preferencePaneIdentifier = PreferencePaneIdentifier.advanced
-	let toolbarItemTitle = "Advanced"
+	let preferencePaneTitle = "Advanced"
 	let toolbarItemIcon = NSImage(named: NSImage.advancedName)!
 
 	override var nibName: NSNib.Name? {

Example/GeneralPreferenceViewController.swift

@@ -3,7 +3,7 @@ import Preferences
 
 final class GeneralPreferenceViewController: NSViewController, PreferencePane {
 	let preferencePaneIdentifier = PreferencePaneIdentifier.general
-	let toolbarItemTitle = "General"
+	let preferencePaneTitle = "General"
 	let toolbarItemIcon = NSImage(named: NSImage.preferencesGeneralName)!
 
 	override var nibName: NSNib.Name? {

Preferences.xcodeproj/project.pbxproj

@@ -61,6 +61,7 @@
 		50A412F32196B70100E4A5A8 /* PreferencesStyle.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; lineEnding = 0; path = PreferencesStyle.swift; sourceTree = "<group>"; usesTabs = 1; };
 		50A412F52196E87900E4A5A8 /* SegmentedControlStyleViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; lineEnding = 0; path = SegmentedControlStyleViewController.swift; sourceTree = "<group>"; usesTabs = 1; };
 		50A412F72196EAF200E4A5A8 /* ToolbarItemStyleViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; lineEnding = 0; path = ToolbarItemStyleViewController.swift; sourceTree = "<group>"; usesTabs = 1; };
+		50F9AE80225773A0005D7DC3 /* readme.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = readme.md; sourceTree = "<group>"; usesTabs = 1; };
 		E3194E4022573FF3006FE775 /* util.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; lineEnding = 0; path = util.swift; sourceTree = "<group>"; usesTabs = 1; };
 		E34E9EE720E6149B002F8F86 /* PreferencesExample.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = PreferencesExample.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		E34E9EE920E6149B002F8F86 /* AppDelegate.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; lineEnding = 0; path = AppDelegate.swift; sourceTree = "<group>"; usesTabs = 1; };
@@ -127,6 +128,7 @@
 		OBJ_5 = {
 			isa = PBXGroup;
 			children = (
+				50F9AE80225773A0005D7DC3 /* readme.md */,
 				OBJ_6 /* Package.swift */,
 				OBJ_7 /* Sources */,
 				E34E9EE820E6149B002F8F86 /* Example */,

Sources/Preferences/PreferencePane.swift

@@ -10,7 +10,7 @@ public struct PreferencePaneIdentifier: Equatable, RawRepresentable {
 
 public protocol PreferencePane: AnyObject {
 	var preferencePaneIdentifier: PreferencePaneIdentifier { get }
-	var toolbarItemTitle: String { get }
+	var preferencePaneTitle: String { get }
 	var toolbarItemIcon: NSImage { get }
 	var viewController: NSViewController { get }
 }

Sources/Preferences/PreferencesTabViewController.swift

@@ -80,6 +80,7 @@ final class PreferencesTabViewController: NSViewController, PreferencesStyleCont
 		defer {
 			activeTab = index
 			preferencesStyleController.selectTab(index: index)
+			updateWindowTitle(tabIndex: index)
 		}
 
 		if activeTab == nil {
@@ -93,6 +94,18 @@ final class PreferencesTabViewController: NSViewController, PreferencesStyleCont
 		}
 	}
 
+	private func updateWindowTitle(tabIndex: Int) {
+		self.window.title = {
+			if preferencePanes.count > 1 {
+				return preferencePanes[tabIndex].preferencePaneTitle
+			} else {
+				let preferences = String(System.localizedString(forKey: "Preferences…").dropLast())
+				let appName = Bundle.main.appName
+				return "\(appName) \(preferences)"
+			}
+		}()
+	}
+
 	/// Cached constraints that pin childViewController views to the content view
 	private var activeChildViewConstraints = [NSLayoutConstraint]()
 

Sources/Preferences/PreferencesWindowController.swift

@@ -30,7 +30,6 @@ public final class PreferencesWindowController: NSWindowController {
 		)
 		super.init(window: window)
 
-		window.title = String(System.localizedString(forKey: "Preferences…").dropLast())
 		window.contentViewController = tabViewController
 		tabViewController.isAnimated = animated
 		tabViewController.configure(preferencePanes: preferencePanes)

Sources/Preferences/SegmentedControlStyleViewController.swift

@@ -62,7 +62,7 @@ final class SegmentedControlStyleViewController: NSViewController, PreferencesSt
 			var maxSize = CGSize.zero
 
 			for preference in preferences {
-				let title = preference.toolbarItemTitle
+				let title = preference.preferencePaneTitle
 				let titleSize = title.size(
 					withAttributes: [
 						.font: NSFont.systemFont(ofSize: NSFont.systemFontSize(for: .regular))
@@ -87,7 +87,7 @@ final class SegmentedControlStyleViewController: NSViewController, PreferencesSt
 		segmentedControl.frame = CGRect(x: 0, y: 0, width: segmentWidth, height: segmentHeight)
 
 		for (index, preference) in preferences.enumerated() {
-			segmentedControl.setLabel(preference.toolbarItemTitle, forSegment: index)
+			segmentedControl.setLabel(preference.preferencePaneTitle, forSegment: index)
 			segmentedControl.setWidth(segmentSize.width, forSegment: index)
 			if let cell = segmentedControl.cell as? NSSegmentedCell {
 				cell.setTag(index, forSegment: index)
@@ -123,11 +123,11 @@ final class SegmentedControlStyleViewController: NSViewController, PreferencesSt
 		let toolbarItemGroup = NSToolbarItemGroup(itemIdentifier: toolbarItemIdentifier)
 		toolbarItemGroup.view = segmentedControl
 		toolbarItemGroup.subitems = preferences.enumerated().map { index, preferenceable -> NSToolbarItem in
-			let item = NSToolbarItem(itemIdentifier: .init("segment-\(preferenceable.toolbarItemTitle)"))
-			item.label = preferenceable.toolbarItemTitle
+			let item = NSToolbarItem(itemIdentifier: .init("segment-\(preferenceable.preferencePaneTitle)"))
+			item.label = preferenceable.preferencePaneTitle
 
 			let menuItem = NSMenuItem(
-				title: preferenceable.toolbarItemTitle,
+				title: preferenceable.preferencePaneTitle,
 				action: #selector(segmentedControlMenuAction),
 				keyEquivalent: ""
 			)

Sources/Preferences/ToolbarItemStyleViewController.swift

@@ -41,7 +41,7 @@ final class ToolbarItemStyleViewController: NSObject, PreferencesStyleController
 		}
 
 		let toolbarItem = NSToolbarItem(itemIdentifier: preferenceIdentifier.toolbarItemIdentifier)
-		toolbarItem.label = preference.toolbarItemTitle
+		toolbarItem.label = preference.preferencePaneTitle
 		toolbarItem.image = preference.toolbarItemIcon
 		toolbarItem.target = self
 		toolbarItem.action = #selector(toolbarItemSelected)

Sources/Preferences/util.swift

@@ -65,3 +65,17 @@ extension NSEvent {
 		return NSEvent.userInteractionEvents.contains(type)
 	}
 }
+
+extension Bundle {
+	var appName: String {
+		return string(forInfoDictionaryKey: "CFBundleDisplayName")
+			?? string(forInfoDictionaryKey: "CFBundleName")
+			?? string(forInfoDictionaryKey: "CFBundleExecutable")
+			?? "<Unknown App Name>"
+	}
+
+	private func string(forInfoDictionaryKey key: String) -> String? {
+		// `object(forInfoDictionaryKey:)` prefers localized info dictionary over the regular one automatically
+		return object(forInfoDictionaryKey: key) as? String
+	}
+}

readme.md

@@ -64,7 +64,7 @@ import Preferences
 
 final class GeneralPreferenceViewController: NSViewController, PreferencePane {
 	let preferencePaneIdentifier = PreferencePaneIdentifier.general
-	let toolbarItemTitle = "General"
+	let preferencePaneTitle = "General"
 	let toolbarItemIcon = NSImage(named: NSImage.preferencesGeneralName)!
 
 	override var nibName: NSNib.Name? {
@@ -87,7 +87,7 @@ import Preferences
 
 final class AdvancedPreferenceViewController: NSViewController, PreferencePane {
 	let preferencePaneIdentifier = PreferencePaneIdentifier.advanced
-	let toolbarItemTitle = "Advanced"
+	let preferencePaneTitle = "Advanced"
 	let toolbarItemIcon = NSImage(named: NSImage.advancedName)!
 
 	override var nibName: NSNib.Name? {
@@ -160,7 +160,7 @@ lazy var preferencesWindowController = PreferencesWindowController(
 ```swift
 public protocol PreferencePane: AnyObject {
 	var preferencePaneIdentifier: PreferencePaneIdentifier { get }
-	var toolbarItemTitle: String { get }
+	var preferencePaneTitle: String { get }
 	var toolbarItemIcon: NSImage { get } // Not required when using the .`segmentedControl` style
 }
 
@@ -185,6 +185,17 @@ As usual, call `NSWindowController#close()` to close the preferences window.
 
 ## FAQ
 
+### How can I localize the window title?
+
+The `PreferencesWindowController` adheres to the [Apple HIG](https://developer.apple.com/design/human-interface-guidelines/macos/app-architecture/preferences/) and uses this set of rules to determine the window title:
+
+- **Multiple preference panes:** Uses the currently selected `preferencePaneTitle` as the window title. Localize your `preferencePaneTitle`s to get localized window titles.
+- **Single preference pane:** Sets the window title to `APPNAME Preferences`. The app name is obtained from your app's bundle. You can localize its `Info.plist` to customize the title. The `Preferences` part is taken from the "Preferences…" menu item, see #12. The order of lookup for the app name from your bundle:
+	1. `CFBundleDisplayName`
+	2. `CFBundleName`
+	3. `CFBundleExecutable`
+	4. Fall back to `"<Unknown App Name>"` to show you're missing some settings.
+
 ### How is it better than [`MASPreferences`](https://github.com/shpakovski/MASPreferences)?
 
 - Written in Swift. *(No bridging header!)*