iOS UIAlertController简单创建以及在AppDelegate中的使用

1、UIAlertController的创建

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示" message:@"您的账号在其他地方登录" preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction *yesAction = [UIAlertAction actionWithTitle:@"登录" style:UIAlertActionStyleDefault handler:^(UIAlertAction *_Nonnull action) {

       NSLog(@"yes");

}];

UIAlertAction *noAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleDefault handler:^(UIAlertAction *_Nonnull action) {

       NSLog(@"no");

}];

[alertController addAction:noAction];

[alertController addAction:yesAction];

[self presentViewController:alertController animated:YES completion:nil];

2、添加在AppDelegate中的方法

UIWindow *alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds]; alertWindow.rootViewController = [[UIViewController alloc] init];
alertWindow.windowLevel = UIWindowLevelAlert + 1;
[alertWindow makeKeyAndVisible];
[alertWindow.rootViewController presentViewController:alertController animated:YES completion:nil];