Question

我正在尝试从按钮操作推送视图控制器。我能够推动我的视图控制器并查看第二个视图控制器页面。现在我点击后退按钮再来到我的第一个视图控制器。现在，当我再次按下按钮时，我的应用程序崩溃，而[self.navigationController pushViewController:about animated:NO];

没有任何日志消息

这是我的代码，

FirstVC.m

- (IBAction) proceedButton:(id)sender {
    if(news == nil) {
        news = [NewsViewController instantiate];
    }
    [UIView  beginAnimations:@"ShowNews" context: nil];
    [UIView setAnimationCurve: UIViewAnimationCurveEaseInOut];
    [UIView setAnimationDuration:0.75];
     self.navigationController.navigationBarHidden = NO;
     UIBarButtonItem *back = [[UIBarButtonItem alloc] initWithTitle : @"Back"
                                                         style : UIBarButtonItemStyleDone
                                                        target : nil
                                                        action : nil];
self.navigationItem.backBarButtonItem = back;
[self.navigationController pushViewController:news animated:NO];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.navigationController.view cache:NO];
[UIView commitAnimations];

}

SecondVC.m

+ (instancetype)instantiate {
    UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"NewsScreen" bundle: nil];
return (NewsViewController *)[mainStoryboard instantiateViewControllerWithIdentifier: @"About"];
}


- (void)viewDidLoad
{
    [super viewDidLoad];

    self.navigationController.navigationBarHidden = NO;
    .....
    .....
}

导航控制器的已检查值，尝试将我的动画更改为YES。但它不起作用。请帮助。 TIA。

app再次按下视图控制器时崩溃

0 个答案: