Question

我正在尝试使用Robert Ryan制作的Edge Swipe Demonstration课程 https://github.com/robertmryan/edge-swipe-demonstration

当我使用我制作的newcontroller更改firstviewcontroller时使用它它在NSAssert线上显示我的错误

这是EdgeSwipeSegue.m代码

@implementation EdgeSwipeSegue

- (void)perform
{
    UIViewController *source = self.sourceViewController;
    id <ParentControllerDelegate>parent = (id)source.parentViewController;
    if(parent==nil){
        NSLog(@"Parent is nil");
    }

    NSAssert([parent conformsToProtocol:@protocol(ParentControllerDelegate)], @"Parent does not conform to ParentControllerDelegate; parent = %@", parent);

    [parent pushChildViewController:self.destinationViewController];
}

我有BarButton，我拖到secondviewcontroller并选择了edgeSegue，但也许我错过了一些东西

为什么断言失败？

Answer 1

让我们试试：

// I assume that you have NewViewController

// in NewViewController.h
@interface NewViewController : UIViewController < ParentControllerDelegate >

//in NewViewController.m : just implement method is declared in ParentControllerDelegate

Answer 2

好的，我自己找到了答案

我有这个雇佣军

 - ParentViewController(ContainerView)
   - NavigationController
     - Viewcontroller

所以这个id parent =（id）source.parentViewController;给了我navigationviewcontroller而不是我需要的parentviewcontroller

所以像这样解决了

UIViewcontroller *cont = self.sourceViewController;
UIViewController *source = con.navigationController;

并且有效

断言失败Custom Segue

2 个答案: