flutter_nayou/macos/Runner/AppDelegate.swift

import Cocoa
import FlutterMacOS

@NSApplicationMain
class AppDelegate: FlutterAppDelegate {
  override func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
    return false
  }

    override func applicationShouldHandleReopen(_ sender: NSApplication, hasVisibleWindows flag: Bool)
      -> Bool
    {
      if !flag {
        for window in NSApp.windows {
          if !window.isVisible {
            window.setIsVisible(true)
          }
          window.makeKeyAndOrderFront(self)
          NSApp.activate(ignoringOtherApps: true)
        }
      }
      return true
    }

}