xcode 如何以编程方式定义 AutoLayout 约束以允许将视图固定到其超级视图的边缘
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How to programmatically define AutoLayout constraint to allow a view to be pinned to the edges of its superview
提问by SasukeIsCool
I've just started trying my hands on AutoLayout and don't quite get it.
我刚刚开始尝试使用 AutoLayout，但不太明白。
Can anyone please show me how exactly to programmaticallypin a view to its superview such that the space between the edges of the view and the edges of the superview is 0. (Essentially, I want the view to still cover the screen when in landscape)
任何人都可以告诉我如何以编程方式将视图固定到其超级视图，以便视图边缘和超级视图边缘之间的空间为 0。（本质上，我希望视图在横向时仍能覆盖屏幕）
Thanks
谢谢
in the end, this was how I solved it: (vc.view is the child view and self.view is the parent)
最后，我是这样解决的：（vc.view 是子视图，self.view 是父视图）
/* pin Left of child to left of parent */
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:vc.view
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:0]];
/* pin Right of child to right of parent */
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:vc.view
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:0]];
/* pin top of child to bottom of nav bar(or status bar if no nav bar) */
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:vc.view
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.topLayoutGuide
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:0]];
/* pin Top of nav bar to bottom of child view */
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.bottomLayoutGuide
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:vc.view
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:0]];
回答by valbuev
I think you should create forexample two constraints: to the left edge with value = 0 and right edge with value = 0. Also you can create constrains to the left edge and width = parent width.
我认为您应该创建例如两个约束：值 = 0 的左边缘和值 = 0 的右边缘。您也可以创建左边缘和宽度 = 父宽度的约束。
[NSLayoutConstraint constraintWithItem:child_view attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual toItem:parent_view
attribute:NSLayoutAttributeWidth multiplier:1.0 constant:0.0];
回答by ERbittuu
You can use like
你可以使用像
[view.superview addConstraint:[NSLayoutConstraint constraintWithItem:view.view
attribute:NSLayoutAttributeLeading
relatedBy:NSLayoutRelationEqual
toItem:view.superview
attribute:NSLayoutAttributeLeading
multiplier:1.0
constant:0]];
