iOS copyWithZone仅在使用设备时无法识别选择器

Question

我正在开发一款iPad应用程序，只有在sqlite数据库中存在某些数据时才启动初始屏幕，如下所示：

if ((int)[MyStore sharedInstance].mode < 0) 
{
    self.connectionSettingsViewController = [[[ConnectionSettingsViewController alloc] initWithNibName:@"ConnectionSettingsModalViewController" bundle:nil] autorelease];
    self.connectionSettingsViewController.view.transform = CGAffineTransformMakeRotation(M_PI_2); 
    self.connectionSettingsViewController.delegate = self;
    self.launchScreen = [[[UIView alloc] initWithFrame:CGRectMake(-256, 0, 1024, 768)] autorelease];
    [self.launchScreen addSubview:self.connectionSettingsViewController.view];
    [self.window addSubview:self.launchScreen];
}

该代码位于app委托中。我面临的问题是，这在iOS模拟器中工作正常，但是当我尝试在iPad上运行时，我收到以下错误：

[someViewController copyWithZone:] unrecognized selector sent to instance.

Answer 1

UIViewController未实现NSCopying协议。除非您在自己的UIViewController子类中实现了NSCopying，否则视图控制器将不会响应-copyWithZone:。