ios - UIAlertView 在应用程序的最开始处 :didFinishLaunchingWithOptions:

Question

我在应用程序一开始就有以下内容:didFinishLaunchingWithOptions:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

    UIAlertView * alertView = [[UIAlertView alloc] initWithTitle:@"Reminder:" message:@"foo" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alertView show];
    NSLog(@"%@ is the parent view",[alertView superview]); // prints "(null)"

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    ...
}

并且 UIAlertView 仍然出现。这怎么行得通？

Answer 1

警报 View 显示在自己的窗口中。但是，直到运行循环有机会运行时，这种情况才会发生。当您记录警报 View 的 super View 时，警报尚未显示，这就是您得到 (null) 的原因。