声明选择器 presentviewcontroller

Question

你好，我有个小问题。

我收到了一个项目的申请，但它是一个有点旧的申请 (IOS 7)。

我在 Internet 上看到了如何使用旧的 UIAlertView 的 INSTEAD 更新 UIAlertController。

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];*/

我收到一个我不明白的错误：

'RFduino' 没有可见的@interface 声明了选择器 'presentViewController: animated: completion'

Answer 1

presentViewController: animated: completion:是UIViewController的一个方法。您调用此方法的 class 是 UIViewController 的子 class 吗？

Answer 2

而不是使用这个：

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

试试这个：

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:^{}];

声明选择器 presentviewcontroller

declares the selector presentviewcontroller

interface

animated

ios

presentviewcontroller