使用 SnapKit 到纵横比和更小的尺寸

Question

我试图在 SnapKit 中创建此布局的约束，但我很难设置最大大小 (lessThanOrEqual)。

let maxWidthContainer: CGFloat = 435
let maxHeightContainer: CGFloat = 600

containerView.snp.makeConstraints {
    $0.width.equalTo(containerView.snp.height).multipliedBy(maxWidthContainer / maxHeightContainer)
    $0.centerX.centerY.equalToSuperview()
    $0.leading.trailing.equalToSuperview().inset(38).priorityLow()
}

Answer 1

如果我明白你要做什么，应该这样做：

    let v = UIView()
    v.backgroundColor = .blue
    view.addSubview(v)

    let maxWidthContainer: CGFloat = 435
    let maxHeightContainer: CGFloat = 600

    v.snp.makeConstraints { (make) in
        // centered X and Y
        make.centerX.centerY.equalToSuperview()

        // at least 38 points "padding" on all 4 sides

        // leading and top >= 38
        make.leading.top.greaterThanOrEqualTo(38)

        // trailing and bottom <= 38
        make.trailing.bottom.lessThanOrEqualTo(38)

        // width ratio to height
        make.width.equalTo(v.snp.height).multipliedBy(maxWidthContainer/maxHeightContainer)

        // width and height equal to superview width and height with high priority (but not required)
        // this will make it as tall and wide as possible, until it violates another constraint
        make.width.height.equalToSuperview().priority(.high)

        // max height
        make.height.lessThanOrEqualTo(maxHeightContainer)
    }