基本使用
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"標題" message:@"標題的提示信息" preferredStyle:UIAlertControllerStyleAlert];
[alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
}]];
[alertController addAction:[UIAlertAction actionWithTitle:@"確定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
}]];
[self presentViewController:alertController animated:YES completion:nil];
