我有一个滚动视图，我想在 viewDidLoad 方法中添加到我的超级视图中。我使用以下代码执行此操作：
[self.view addSubview:self.scroll];
NSMutableArray *constraints = [NSMutableArray arrayWithCapacity:4];
[constraints addObject:[NSLayoutConstraint constraintWithItem:self.scroll
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1
constant:0]];
[constraints addObject:[NSLayoutConstraint constraintWithItem:self.scroll
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1
constant:0]];
[constraints addObject:[NSLayoutConstraint constraintWithItem:self.scroll
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeBottom
multiplier:1
constant:0]];
[constraints addObject:[NSLayoutConstraint constraintWithItem:self.scroll
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeHeight
multiplier:0.5
constant:0]];
[self.view addConstraints:constraints];
滚动视图旨在放置在视图的底部，它的高度应该是超级视图高度的一半。
我收到以下错误：
Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)
（“”、“”、“”、“”）
将尝试通过打破约束来恢复
请有人告诉我我做错了什么？谢谢你。