Constraints not updating with device orientation change

问题

I have a color slider in a tableView cell that extends from the label to the trailingAnchor of the cell. The issue I am having is when the device orientation changes the color slider does not update its constraints and no longer extends the full length of the cell. Below is my code to set up the constraints on the color slider. Below are images to show the issue I am having. If my phone is already in landscape orientation when I present this scene the color slider extends the full length of the cell as desired. However, if I switch to landscape when already viewing this scene the slider appears as below. Here is the full code if that helps.

  func configureColorSlider() {
    let colorSlider = ColorSlider()
    let xCell = colorCell.contentView.bounds.width
    let yCell = colorCell.contentView.bounds.height
    colorSlider.frame = CGRect(x: xCell / 4, y: yCell / 4, width: 200, height: 24)
    colorSlider.orientation = .horizontal
    colorSlider.addTarget(self, action: #selector(ConfigureTimestampTableViewController.changedColor(_:)), for: .valueChanged)

    colorCell.contentView.addSubview(colorSlider)

    colorSlider.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([colorSlider.leadingAnchor.constraint(equalTo: colorLabel.trailingAnchor, constant: 8),
                                 colorSlider.trailingAnchor.constraint(equalTo: colorCell.contentView.trailingAnchor, constant: -8),
                                 colorSlider.topAnchor.constraint(equalTo: colorCell.contentView.topAnchor, constant: 8),
                                 colorSlider.bottomAnchor.constraint(equalTo: colorCell.contentView.bottomAnchor, constant: -8) ])


  }

回答1:

CALayers will not be resized in response to their parent UIView being resized, whether by auto layout or manually.

You just need to add code to your ColorSlider that updates the layer when the size/position of the ColorSilider changes. Luckily, there is a method on UIView that is specifically for this.

override func layoutSubviews() {
    super.layoutSubviews()
    gradientLayer.frame = bounds
}

来源：https://stackoverflow.com/questions/40681639/constraints-not-updating-with-device-orientation-change