如何在windowDidBecomeKey中弹出窗口

Question

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(windowDidBecomeKey:) name:NSWindowDidBecomeKeyNotification object:nil];

我添加了name:NSWindowDidBecomeKeyNotification的观察者并处理它

-(void)windowDidBecomeKey:(NSNotification*)notification
{
      NSWindowController *xxx;
      [xxx showWindow:self];
}

然后windowDidBecomeKey将被称为无限循环，导致无限循环。所以有人知道如何实现这个在激活窗口时显示弹出窗口的函数吗？