声明选择器presentviewcontroller [英] declares the selector presentviewcontroller

问题描述

你好，我有一个小问题。

Hello I have a little problem.

我有一个项目的应用程序，但是它有点旧了（IOS 7）。

I got an application for a project, but it is a somewhat old application (IOS 7).

我在互联网上看到了如何使用旧版UIAlertView的INSTEAD更新UIAlertController。

I saw on the internet how to update the UIAlertController Using INSTEAD of good-old UIAlertView.

if (error.code) {
cancelBlock = block;


UIAlertController *alert = [UIAlertController alertControllerWithTitle: @"Message"
                                                                    message: @"Peripheral Disconnected with Error"
                                                             preferredStyle: UIAlertControllerStyleAlert];

UIAlertAction *alertAction = [UIAlertAction actionWithTitle: @"OK"
                                                      style: UIAlertActionStyleDestructive
                                                    handler: ^(UIAlertAction *action) {
                                                        NSLog(@"OK");
                                                    }];

[alert addAction: alertAction];

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







/*  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Peripheral Disconnected with Error"
                                                    message:error.description
                                                   delegate:self
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
    [alert show];*/

我收到一个我不理解的错误：

I get an error that I do not understand:

'RFduino'的可见@interface声明选择器'presentViewController：animated：completion'

No visible @interface for 'RFduino' declared the selector 'presentViewController: animated: completion'

推荐答案

而不是使用它：

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

尝试一下：

UIViewController *viewController = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
if ( viewController.presentedViewController && !viewController.presentedViewController.isBeingDismissed ) {
    viewController = viewController.presentedViewController;
}

NSLayoutConstraint *constraint = [NSLayoutConstraint 
    constraintWithItem:alert.view 
    attribute:NSLayoutAttributeHeight 
    relatedBy:NSLayoutRelationLessThanOrEqual 
    toItem:nil 
    attribute:NSLayoutAttributeNotAnAttribute 
    multiplier:1 
    constant:viewController.view.frame.size.height*2.0f];

[alert.view addConstraint:constraint];
[viewController presentViewController:alert animated:YES completion:^{}];

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