“宽度等于高度"Interface Builder 中的约束

问题描述

我找不到在 Interface Builder 中创建方形"约束的方法，即宽度等于高度".我想有可能以编程方式添加这样的约束.IB有什么我可以做的吗?也许我只是没看到?看似微不足道，却找不到.

I can't find a way to create a 'square' constraint, meaning 'width equals height' in Interface Builder. I guess it's possible to add such constraint programmatically. Is there something I can do in IB? Maybe I just don't see it? It seems trivial, yet I can't find it.

推荐答案

更新 Xcode 5.1b5

Ctrl+单击并从视图中拖动并在指针位于视图上方时释放.选择纵横比".它将创建一个约束，其中第一项和第二项是视图.

Ctrl+click and drag from a view and release while the pointer is over the view. Select "Aspect Ratio". It will create a constraint where the first and second item is the view.

Xcode 5.1 之前

你不能因为宽度/高度编辑器缺少与另一个属性相关的字段或设置比率:

You can't because the width/height editor lacks the fields to relate to another property or set the ratio:

因此，您无法在 Interface Builder 中表达以下代码:

Therefore, you can't express the following code in Interface Builder:

CGFloat ratio = 1.0;
NSLayoutConstraint *constraint = [NSLayoutConstraint
    constraintWithItem:myView
    attribute:NSLayoutAttributeWidth
    relatedBy:NSLayoutRelationEqual
    toItem:myView
    attribute:NSLayoutAttributeHeight
    multiplier:ratio
    constant:0];
constraint.priority = 1000;
[myView.superview addConstraint:constraint];

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