Question

我在运行时创建了一个UIButton。当我点击按钮时，我的应用程序将崩溃并显示错误无法在视图上安装约束。。

-(void)loadView{

    CGRect fullScreenRect=[[UIScreen mainScreen] applicationFrame];
    scrollView=[[UIScrollView alloc] initWithFrame:fullScreenRect];
    scrollView.contentSize=CGSizeMake(320,758);

    scrollView.contentInset=UIEdgeInsetsMake(20.0,0.0,44.0,0.0);
    scrollView.scrollIndicatorInsets=UIEdgeInsetsMake(20.0,0.0,44.0,0.0);

    UIImage *red = [UIImage imageNamed:@"red.png"];

    UIButton *cancelButton = [[UIButton alloc]initWithFrame:CGRectMake(165, y, 142, 35)];
    cancelButton.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
    cancelButton.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;
    [cancelButton setTitle:@"Cancel" forState:UIControlStateNormal];
    [cancelButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    [cancelButton.titleLabel setFont:[UIFont boldSystemFontOfSize:15]];
    [cancelButton setBackgroundImage:red forState:UIControlStateNormal];
    [cancelButton addTarget:self action:@selector(cancelButtonPressed:) forControlEvents:UIControlEventTouchUpInside];

    [scrollView addSubview:cancelButton];
}

- (IBAction)cancelButtonPressed:(id)sender {
    [self dismissViewControllerAnimated:YES completion:nil]; --> error
}

错误

由于未捕获的异常'NSGenericException'而终止应用程序，原因：'无法在视图上安装约束。约束是否引用了视图子树之外的内容？那是违法的。约束：view：; layer =; contentOffset：{0,0}＆gt;'

NSGenericException'，原因：'无法在视图上安装约束

0 个答案: