Question

我想提出UIAlertController UIAlertControllerStyleAlert样式，同时解除UIAlertController样式UIAlertControllerStyleActionSheet。换句话说，我想在从操作表中点击选项后显示警报视图。但是没有显示警报视图，只显示日志中的此消息：

尝试加载视图控制器的视图不允许解除分配并可能导致未定义的行为

这是我的代码：

UIAlertController *actionSheet = [UIAlertController alertControllerWithTitle:@"MyApp" message:@"Info" preferredStyle:UIAlertControllerStyleActionSheet];

    [actionSheet addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {

        // Cancel button tappped.
        [self dismissViewControllerAnimated:YES completion:^{
        }];
    }]];

    [actionSheet addAction:[UIAlertAction actionWithTitle:@"Credits" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

        UIAlertController * alert=   [UIAlertController
                                      alertControllerWithTitle:@"Credits"
                                      message:@"Here some text in the alertview..."
                                      preferredStyle:UIAlertControllerStyleAlert];

        UIAlertAction* yesButton = [UIAlertAction
                                    actionWithTitle:@"Close"
                                    style:UIAlertActionStyleDefault
                                    handler:^(UIAlertAction * action)
                                    {
                                        //Handel your yes please button action here


                                    }];

        [alert addAction:yesButton];

        [self dismissViewControllerAnimated:YES completion:^{
            // try to present the alertview
            [self presentViewController:alert animated:YES completion:nil];
        }];
    }]];

    // Present action sheet.
    [self presentViewController:actionSheet animated:YES completion:nil];

动作表正在运行，而警报视图没有。动作表来自UITableViewController。非常感谢每一位帮助，提前谢谢

Answer 1

修正了......代码。您无需关闭以加载AlertController。

UIAlertController *actionSheet = [UIAlertController alertControllerWithTitle:@"MyApp" message:@"Info" preferredStyle:UIAlertControllerStyleActionSheet];

[actionSheet addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {

    // Cancel button tappped.
    [self dismissViewControllerAnimated:YES completion:^{
    }];
}]];

[actionSheet addAction:[UIAlertAction actionWithTitle:@"Credits" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

    UIAlertController * alert=   [UIAlertController
                                  alertControllerWithTitle:@"Credits"
                                  message:@"Here some text in the alertview..."
                                  preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction* yesButton = [UIAlertAction
                                actionWithTitle:@"Close"
                                style:UIAlertActionStyleDefault
                                handler:^(UIAlertAction * action)
                                {
                                    //Handel your yes please button action here


                                }];

    [alert addAction:yesButton];

    [self presentViewController:alert animated:YES completion:nil];
}]];

// Present action sheet.
[self presentViewController:actionSheet animated:YES completion:nil];

刚刚在一个空项目中试过，在 - （void）viewDidAppear：（BOOL）中添加了代码动画并且工作正常。

希望有所帮助

Answer 2

问题是你在[self dismissViewControllerAnimated]的完成块中调用[self presentViewController]。

您尝试呈现的警报视图控制器正在被释放，因为它是自视图控制器中已被解除的局部变量。

在另一个UIAlertController原因中显示UIAlertController导致在取消分配时尝试加载视图控制器的视图是不允许的

2 个答案: