oc UIAlertController封装

#define SHOWALERT(MESSAGE) \
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示" message:MESSAGE preferredStyle:UIAlertControllerStyleAlert]; \
UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:nil]; \
[alertController addAction:okAction]; \
UIViewController *vc = [UIApplication sharedApplication].windows[].rootViewController;\
[vc presentViewController:alertController animated:YES completion:nil];