Snapkit and UILabel's rotation

问题

I have:

UIView (container)
UIView. subview of (1) - Dark blue in the image below
UIView. subview of (1) - Purple in the image below
UILabel. edges.equalToSuperview()

What I'm trying to accomplish:

The thing is, I want the UILabel to be rotated 3pi/2 (270°). Once I've done the rotation, it isn't placed correctly.

This is how it looks like by setting edges.equalToSuperview() and the 270°rotation:

I've tried this (but it leads to a crash):

myLabel.makeConstraints { make in
    make.top.equalTo(containerView.snp.left)
    make.right.equalTo(containerView.snp.top)
    make.left.equalTo(containerView.snp.bottom)
    make.bottom.equalTo(containerView.snp.right)
}

The crash description:

*** Terminating app due to uncaught exception 'NSInvalidLayoutConstraintException', reason: 'Constraint improperly relates anchors of incompatible types: <SnapKit.LayoutConstraint:0x6100000ad8c0@MyClass.swift#250 MyProject.MyLabel:0x7fcc2201ca80.top == UIView:0x7fcc2201bd30.left>'

Any ideas what I could do here?

回答1:

I have done it using default autolayout and i like that much too. :)

Here is the function.

func makeLabel() {
        //Creating stackview
        let stackView = UIStackView()
        view.addSubview(stackView)
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.alignment = .fill
        stackView.distribution = .fillEqually
        stackView.axis = .vertical

        //Creating blueView
        let blueView = UIView()
        blueView.backgroundColor = UIColor.darkGray
        blueView.translatesAutoresizingMaskIntoConstraints = false
        stackView.addArrangedSubview(blueView)
        blueView.widthAnchor.constraint(equalToConstant: 100).isActive = true

        //Creating purpleView
        let purpleView = UIView()
        purpleView.backgroundColor = UIColor.purple
        purpleView.translatesAutoresizingMaskIntoConstraints = false
        stackView.addArrangedSubview(purpleView)

        stackView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
        stackView.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
        stackView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true

        //Creating rotated label
        let label = UILabel()
        view.addSubview(label)
        label.transform = CGAffineTransform.init(rotationAngle: -CGFloat.pi/2)
        label.textColor = UIColor.white
        label.text = "This is my Rotated Text"
        label.font = UIFont.systemFont(ofSize: 25)
        label.translatesAutoresizingMaskIntoConstraints = false
        label.centerXAnchor.constraint(equalTo: stackView.centerXAnchor, constant: 0).isActive = true
        label.centerYAnchor.constraint(equalTo: stackView.centerYAnchor, constant: 0).isActive = true


    }

And here is the output.

Portrait:

Landscape

回答2:

For anyone interested in elk_cloner's answer using Snapkit:

myLabel.snp.makeConstraints { make in
    make.centerX.equalTo(containerView.snp.centerX)
    make.centerY.equalTo(containerView.snp.centerY)
}

来源：https://stackoverflow.com/questions/44507242/snapkit-and-uilabels-rotation

标签

ios

swift

autolayout

snapkit