In macOS development, handling window events is crucial for creating responsive and interactive applications. While the concept of "Window+Events" is more commonly associated with Windows OS, macOS has its own robust system for managing window events through the Cocoa framework and the AppKit library. This article will guide you through the process of handling window events in macOS using Swift and Objective-C, providing practical examples to help you get started.

Examples:

1. Setting Up a Basic macOS Application in Swift:

   import Cocoa
   
   @NSApplicationMain
   class AppDelegate: NSObject, NSApplicationDelegate {
   
      var window: NSWindow!
   
      func applicationDidFinishLaunching(_ aNotification: Notification) {
          // Create the window
          let screenSize = NSScreen.main!.frame
          let windowSize = NSMakeRect(screenSize.size.width / 4, screenSize.size.height / 4, screenSize.size.width / 2, screenSize.size.height / 2)
          window = NSWindow(contentRect: windowSize, styleMask: [.titled, .closable, .resizable], backing: .buffered, defer: false)
          window.title = "My macOS Application"
          window.makeKeyAndOrderFront(nil)
   
          // Register for window events
          NotificationCenter.default.addObserver(self, selector: #selector(windowDidResize(_:)), name: NSWindow.didResizeNotification, object: window)
      }
   
      @objc func windowDidResize(_ notification: Notification) {
          print("Window resized to: \(window.frame.size)")
      }
   }

   In this example, a basic macOS application is created using Swift. A window is set up, and an event listener is registered to handle the window resize event.

2. Handling Window Events in Objective-C:

   #import <Cocoa/Cocoa.h>
   
   @interface AppDelegate : NSObject <NSApplicationDelegate>
   @property (strong, nonatomic) NSWindow *window;
   @end
   
   @implementation AppDelegate
   
   - (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
      // Create the window
      NSRect screenSize = [[NSScreen mainScreen] frame];
      NSRect windowSize = NSMakeRect(screenSize.size.width / 4, screenSize.size.height / 4, screenSize.size.width / 2, screenSize.size.height / 2);
      self.window = [[NSWindow alloc] initWithContentRect:windowSize styleMask:(NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskResizable) backing:NSBackingStoreBuffered defer:NO];
      [self.window set@"My macOS Application"];
      [self.window makeKeyAndOrderFront:nil];
   
      // Register for window events
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(windowDidResize:) name:NSWindowDidResizeNotification object:self.window];
   }
   
   - (void)windowDidResize:(NSNotification *)notification {
      NSLog(@"Window resized to: %@", NSStringFromRect(self.window.frame));
   }
   
   @end
   
   int main(int argc, const char * argv[]) {
      return NSApplicationMain(argc, argv);
   }

   This Objective-C example demonstrates similar functionality, setting up a window and handling the resize event.