以编程方式添加时rightAnchor约束不适用-Swift [英] rightAnchor constraint did not apply when added programmatically - swift

问题描述

当我添加rightAnchor约束时，常量= 20不适用.在leftAnchor中可以

When I Added rightAnchor constraint, constant= 20 did not apply. In leftAnchor is ok

override init(frame: CGRect) {
    super.init(frame: frame)

    addSubview(collectionView)
    collectionView.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([collectionView.leftAnchor.constraint(equalTo: leftAnchor, constant: 20),
                                 collectionView.topAnchor.constraint(equalTo: self.topAnchor),
                                 collectionView.rightAnchor.constraint(equalTo: rightAnchor, constant: 20),
                                 collectionView.heightAnchor.constraint(equalTo: self.heightAnchor)])
}

有人可以帮助我吗?

推荐答案

我非常强烈地认为这就是您想要在rightAnchor上执行的操作.

I have a really strong feeling that this is what you wanted to do there for rightAnchor.

collectionView.rightAnchor.constraint(equalTo: rightAnchor, constant: -20)

如果要从右侧或底部填充，则应使用负值.

If you want padding from the right or bottom you should use negative values.

经验法则:东西的左边或上方都是负面的.

Rule of thumb: Whatever is left or upwards of something is negative.

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