IGListKit/Examples/Examples-iOS/IGListKitExamples/Views/LabelCell.swift
Ryan Nystrom 6bdcac81d8 Layout invalidation API
Summary:
Adding a new layout-invalidation API, telling the layout object to query and rebuild the layout for all items in the section controller. This works with `UICollectionViewFlowLayout` and should work with other custom layouts (including our own).

Issue fixed: #360, #459

- [x] All tests pass. Demo project builds and runs.
- [x] I added tests, an experiment, or detailed why my change isn't tested.
- [x] I added an entry to the `CHANGELOG.md` for any breaking changes, enhancements, or bug fixes.
Closes https://github.com/Instagram/IGListKit/pull/499

Reviewed By: jessesquires

Differential Revision: D4590274

Pulled By: rnystrom

fbshipit-source-id: f87235be4e6c024bf979b831a8938be68895e011
2017-02-21 15:30:56 -08:00

74 lines
2.7 KiB
Swift

/**
Copyright (c) 2016-present, Facebook, Inc. All rights reserved.
The examples provided by Facebook are for non-commercial testing and evaluation
purposes only. Facebook reserves all rights not expressly granted.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
import UIKit
class LabelCell: UICollectionViewCell {
fileprivate static let insets = UIEdgeInsets(top: 8, left: 15, bottom: 8, right: 15)
fileprivate static let font = UIFont.systemFont(ofSize: 17)
static var singleLineHeight: CGFloat {
return font.lineHeight + insets.top + insets.bottom
}
static func textHeight(_ text: String, width: CGFloat) -> CGFloat {
let constrainedSize = CGSize(width: width - insets.left - insets.right, height: CGFloat.greatestFiniteMagnitude)
let attributes = [ NSFontAttributeName: font ]
let options: NSStringDrawingOptions = [.usesFontLeading, .usesLineFragmentOrigin]
let bounds = (text as NSString).boundingRect(with: constrainedSize, options: options, attributes: attributes, context: nil)
return ceil(bounds.height) + insets.top + insets.bottom
}
let label: UILabel = {
let label = UILabel()
label.backgroundColor = .clear
label.numberOfLines = 0
label.font = LabelCell.font
return label
}()
let separator: CALayer = {
let layer = CALayer()
layer.backgroundColor = UIColor(red: 200/255.0, green: 199/255.0, blue: 204/255.0, alpha: 1).cgColor
return layer
}()
override init(frame: CGRect) {
super.init(frame: frame)
contentView.addSubview(label)
contentView.layer.addSublayer(separator)
contentView.backgroundColor = .white
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
let bounds = contentView.bounds
label.frame = UIEdgeInsetsInsetRect(bounds, LabelCell.insets)
let height: CGFloat = 0.5
let left = LabelCell.insets.left
separator.frame = CGRect(x: left, y: bounds.height - height, width: bounds.width - left, height: height)
}
override var isHighlighted: Bool {
didSet {
contentView.backgroundColor = UIColor(white: isHighlighted ? 0.9 : 1, alpha: 1)
}
}
}