[的UIBarButtonItem上海華]：無法識別的選擇發送到實例

Question

我使用的代碼SEGUE：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(UIButton *)sender 
{ 
    menuVC *menuview = [segue destinationViewController]; 
    CGPoint centerOfButton = [sender.superview convertPoint:sender.center toView:nil]; 

    [self.circularTransitionHandler transitionWithDestinationViewController:menuview initialTransitionPoint:centerOfButton]; 
} 

應用崩潰：

終止應用程序由於未捕獲的異常 'NSInvalidArgumentException'，原因： ' - [UIBarButtonItem superview]：發送到實例的無法識別的選擇器0x7ffb74293b10'

Answer 1

您是否嘗試訪問您的輕觸按鈕？所以，當你試圖讓你的按鈕超級查看，應用程序確實崩潰。不幸的是，UIBarButtonItem沒有superview屬性。您需要使用您的UIBarButtonItem的.view。

請更新您這樣的代碼：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
{ 
    menuVC *menuview = [segue destinationViewController]; 
    UIBarButtonItem *item = (UIBarButtonItem *)sender; 
    UIView *view = [item valueForKey:@"view"]; 
    CGPoint centerOfButton = [view convertPoint:view.center toView:nil];  
    [self.circularTransitionHandler transitionWithDestinationViewController:menuview initialTransitionPoint:centerOfButton]; 
} 

見我已經改變了參數類型。

Answer 2

`UIBarButtonItem` does not extend `UIView` thus it has no frame property. 
We can get center point of button like this: 


    - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(UIBarButtonItem *)sender 
    { 
     menuVC *menuview = [segue destinationViewController]; 
     UIView *barView = [sender valueForKey:@"view"]; 
     if (barView) { 
     CGRect buttonFrame = [barView convertPoint: barView.bounds toView:self.view]; 

     CGPoint centerOfButton = CGPointMake(buttonFrame.origin.x + buttonFrame.size.width/2, 
              buttonFrame.origin.y + buttonFrame.size.height/2); 

     [self.circularTransitionHandler transitionWithDestinationViewController:menuview 
                 initialTransitionPoint:centerOfButton]; 
     } 
    }