feat: improves PreferencesPanel UX, partially implements #49

implements requested changes from Code-Review and contains also refactoring and more features and improvements
- Application Wide: changes all exceptions to NSError (required for error handling via sheet in panel)
- PreferencesPanel: adds display of current value of Sliders
- PreferencesPanel: adds validation with visualisation for TextFields (whitelist for KeyCode and ranges for maxScreenUsage & windowDisplayDelay) during editing, window open and close
- PreferencesPanel: adds error sheet (in-window modal) at all known possible errors to display error information and ask the user how to proceed
- PreferencesPanel: removes Restart button (and relaunch code in Application)
- PreferencesPanel: adds Preferences being now live
- PreferencesPanel: removes invisibleText workaround
- PreferencesPanel: adds TextField value save on each keyDown event (if valid and changed)
- PreferencesPanel: adds window activation/deactivation
- PreferencesPanel: changes label texts of some Preferences
- ...

alt-tab-macos.xcodeproj/project.pbxproj

@@ -21,6 +21,7 @@
 		D04BA9CCE02D30C8164A552A /* SystemPermissions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04BA2D2AD6B1CCA3F3A4DD7 /* SystemPermissions.swift */; };
 		D04BAD4DE538FDF7E7532EE2 /* Labels.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04BAD32E130E4A061DC8332 /* Labels.swift */; };
 		D04BAEF78503D7A2CEFB9E9E /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04BAA44C837F3A67403B9DB /* main.swift */; };
+		F02981D5D1E1F62074801CAE /* PreferencesPanelNSTextFieldEditable.swift in Sources */ = {isa = PBXBuildFile; fileRef = F0298F4D7927608A986C320D /* PreferencesPanelNSTextFieldEditable.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -72,6 +73,7 @@
 		D04BAF076A30A1BAFEDBEA66 /* 5 windows - 2 lines.jpg */ = {isa = PBXFileReference; lastKnownFileType = image.jpeg; path = "5 windows - 2 lines.jpg"; sourceTree = "<group>"; };
 		D04BAF249324297C07E31164 /* frontpage.jpg */ = {isa = PBXFileReference; lastKnownFileType = image.jpeg; path = frontpage.jpg; sourceTree = "<group>"; };
 		D04BAFA277EAE3BDDDB61110 /* CHANGELOG.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = CHANGELOG.md; sourceTree = "<group>"; };
+		F0298F4D7927608A986C320D /* PreferencesPanelNSTextFieldEditable.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PreferencesPanelNSTextFieldEditable.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -172,6 +174,7 @@
 				D04BA3F15EAE8D8C39B6F2CF /* Screen.swift */,
 				D04BA2D2AD6B1CCA3F3A4DD7 /* SystemPermissions.swift */,
 				D04BA86768C6503A11ED81FC /* Extensions.swift */,
+				F0298F4D7927608A986C320D /* PreferencesPanelNSTextFieldEditable.swift */,
 			);
 			path = logic;
 			sourceTree = "<group>";
@@ -302,6 +305,7 @@
 				D04BA02DD4152997C32CF50B /* StatusItem.swift in Sources */,
 				D04BA0F3D46BC79544E2B930 /* Extensions.swift in Sources */,
 				D04BAD4DE538FDF7E7532EE2 /* Labels.swift in Sources */,
+				F02981D5D1E1F62074801CAE /* PreferencesPanelNSTextFieldEditable.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

alt-tab-macos/logic/Extensions.swift

@@ -19,15 +19,11 @@ extension Optional {
             return value
         case .none:
             Thread.callStackSymbols.forEach { print($0) }
-            throw "Optional contained nil"
+            throw NSError.make(domain: "Optional", message: "Optional contained nil")
         }
     }
 }
 
-// allow String to be treated as Error (e.g. throw "explanation")
-extension String: Error {
-}
-
 // add String constructor from CGFloat that round up at 1 decimal
 extension String {
     init?(_ cgFloat: CGFloat) {
@@ -39,3 +35,25 @@ extension String {
         self.init(string)
     }
 }
+
+// add recursive lookup in subviews for specific type
+extension NSView {
+    func findNestedViews<T: NSView>(subclassOf: T.Type) -> [T] {
+        return recursiveSubviews.compactMap { $0 as? T }
+    }
+
+    var recursiveSubviews: [NSView] {
+        return subviews + subviews.flatMap { $0.recursiveSubviews }
+    }
+}
+
+// add convenience to NSError
+extension NSError {
+    class func make(domain: String, message: String, code: Int = 9999) -> NSError {
+        return NSError(
+                domain: domain,
+                code: code,
+                userInfo: [NSLocalizedDescriptionKey: message, NSLocalizedFailureReasonErrorKey: message]
+        )
+    }
+}

alt-tab-macos/logic/Preferences.swift

@@ -102,7 +102,7 @@ class Preferences {
             let p = try showOnScreenMacro.labelToMacro[value].orThrow()
             showOnScreen = p.preferences
         default:
-            throw "Tried to update an unknown preference: '\(valueName)' = '\(value)'"
+            throw NSError.make(domain: "Preferences", message: "Tried to update an unknown preference: '\(valueName)' = '\(value)'")
         }
         rawValues[valueName] = value
     }

alt-tab-macos/logic/PreferencesPanelNSTextFieldEditable.swift

@@ -0,0 +1,34 @@
+import Cocoa
+
+class PreferencesPanelNSTextFieldEditable: NSTextField, NSTextFieldDelegate {
+
+    var validationHandler: ((String)->Bool)?
+
+    // protocol method
+    func controlTextDidChange(_ obj: Notification) {
+        visualizeValidationState(isValid())
+        let textField = obj.object as! PreferencesPanelNSTextFieldEditable
+        sendAction(textField.action, to: textField.target)
+    }
+
+    // custom method
+    func visualizeValidationState(_ isValid: Bool) -> Void {
+        if !isValid {
+            wantsLayer = true
+            layer?.borderColor = NSColor.systemRed.cgColor
+            layer?.borderWidth = 1
+        } else {
+            wantsLayer = false
+        }
+    }
+
+    // custom method
+    func isValid() -> Bool {
+        if let handler = validationHandler {
+            return handler(stringValue)
+        }
+
+        return true
+    }
+
+}

alt-tab-macos/ui/Application.swift

@@ -4,7 +4,6 @@ import Cocoa
 class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
     static let name = "AltTab"
     var statusItem: NSStatusItem?
-    var backgroundView: NSVisualEffectView?
     var thumbnailsPanel: ThumbnailsPanel?
     var preferencesPanel: PreferencesPanel?
     var selectedOpenWindow: Int = 0
@@ -28,11 +27,15 @@ class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
         SystemPermissions.ensureAccessibilityCheckboxIsChecked()
         Preferences.loadFromDiskAndUpdateValues()
         statusItem = StatusItem.make(self)
-        thumbnailsPanel = ThumbnailsPanel(self)
-        preferencesPanel = PreferencesPanel()
+        initPreferencesDependentComponents()
         Keyboard.listenToGlobalEvents(self)
     }
 
+    // we put application code here which should be executed on init() and Preferences change
+    func initPreferencesDependentComponents() {
+        thumbnailsPanel = ThumbnailsPanel(self)
+    }
+
     func showUiOrSelectNext() {
         debugPrint("showUiOrSelectNext")
         showUiOrCycleSelection(1)
@@ -58,7 +61,11 @@ class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
         }
     }
 
-    @objc func showPreferencesPanel() {
+    @objc
+    func showPreferencesPanel() {
+        if preferencesPanel == nil {
+            preferencesPanel = PreferencesPanel()
+        }
         Screen.showPanel(preferencesPanel!, Screen.preferredScreen(), .appleCentered)
     }
 
@@ -125,12 +132,4 @@ class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
         return openWindows.count > selectedOpenWindow ? openWindows[selectedOpenWindow] : nil
     }
 
-    func relaunch(afterDelay seconds: TimeInterval = 0.5) -> Never {
-        let task = Process()
-        task.launchPath = "/bin/sh"
-        task.arguments = ["-c", "sleep \(seconds); open \"\(Bundle.main.bundlePath)\""]
-        task.launch()
-        self.terminate(nil)
-        exit(0)
-    }
 }