ios - NSInvalidArgumentException'，原因 : 'Unable to parse constraint format:

Question

NSInvalidArgumentException'，原因:'无法解析约束格式:我计划为问题和答案进行动态自动布局，但在执行 nslayout 约束后出现此错误。

    UIScrollView *view = self.view;
        NSDictionary *viewDictionary = @{@"view":view,
                                         @"control":control  
        };
        NSArray *horizontalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:-0-[view]-0-“  options:0  metrics:nil
        views:viewDictionary];

        NSArray *verticalContraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:-[control]-[view]-"  options:0 metrics:nil
        views:viewDictionary];

        [self.view.superview addConstraints: verticalContraints];
        [self.view addSubview:control];
        [self.view.superview addConstraints:horizontalConstraints];

错误是:

error *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse constraint format: Expected a view H:-0-[view]-0-

Answer 1

在添加约束之前将控制 subview 添加到父 View 。这样，自动布局可以理解添加的约束。

视觉格式语言需要一个“|”用于分隔 super View 边缘的字符。试试这个水平

|-[view]-|

这对于垂直

V:|-[control]-[view]-|