[英]How to set width of UICollectionView on rotation with auto layout programmatically swift
我已经使用自动布局设置了具有自定义尺寸单元的集合视图。 但是,当我旋转设备时,集合视图仍然使用纵向宽度并被切除。 我正在使用流布局,而不是sizeForItemAt方法。
这是我的主视图控制器:
import UIKit
class HomeController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let layout = UICollectionViewFlowLayout()
layout.estimatedItemSize = UICollectionViewFlowLayoutAutomaticSize
layout.minimumLineSpacing = 0
layout.scrollDirection = .vertical
let homeCollectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
homeCollectionView.dataSource = self
homeCollectionView.delegate = self
homeCollectionView.backgroundColor = .orange
homeCollectionView.register(CellTypeOne.self, forCellWithReuseIdentifier: "CellType1")
self.view.addSubview(homeCollectionView)
homeCollectionView.translatesAutoresizingMaskIntoConstraints = false
homeCollectionView.leadingAnchor
.constraint(equalTo: self.view.leadingAnchor).isActive = true
homeCollectionView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
homeCollectionView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
homeCollectionView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return contents.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// code for specific type of cells
}
let contents: [ContentType] = []
另外,这是我的一个牢房:
import UIKit
class CellType1: UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: frame)
setupViews()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
var content: Content? {
didSet {
sectionTextView.text = content?.sectionView
}
}
let sectionTextView: UITextView = {
let textView = UITextView()
textView.contentInset = UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
// textView.backgroundColor = .orange
textView.translatesAutoresizingMaskIntoConstraints = false
textView.textContainerInset = UIEdgeInsetsMake(10, 0, 20, 0)
textView.text = "This is a Section text"
textView.font = UIFont.systemFont(ofSize: 20, weight: .heavy)
textView.textColor = UIColor(red: 76/255, green: 76/255, blue: 77/255, alpha: 1.0)
textView.isEditable = false
textView.isScrollEnabled = false
return textView
}()
func setupViews() {
addSubview(sectionTextView)
let widthAnchorConstraint = sectionTextView.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.size.width - 16)
widthAnchorConstraint.identifier = "sectionTextView Width Anchor Constraint"
widthAnchorConstraint.priority = UILayoutPriority(rawValue: 1000)
widthAnchorConstraint.isActive = true
let topAnchorConstraint = sectionTextView.topAnchor.constraint(equalTo: topAnchor)
topAnchorConstraint.identifier = "sectionTextView Top Anchor Constraint"
topAnchorConstraint.isActive = true
let leftAnchorConstraint = sectionTextView.leftAnchor.constraint(equalTo: leftAnchor)
leftAnchorConstraint.identifier = "sectionTextView Left Anchor Constraint"
leftAnchorConstraint.isActive = true
let rightAnchorConstraint = sectionTextView.rightAnchor.constraint(equalTo: rightAnchor)
rightAnchorConstraint.identifier = "sectionTextView Right Anchor Constraint"
rightAnchorConstraint.priority = UILayoutPriority(rawValue: 999)
rightAnchorConstraint.isActive = true
let bottomAnchorConstraint = sectionTextView.bottomAnchor.constraint(equalTo: bottomAnchor)
bottomAnchorConstraint.identifier = "sectionTextView Bottom Anchor Constraint"
bottomAnchorConstraint.isActive = true
}
}
我已经尝试过按照Sh_Khan的建议使用“自动布局”。 我更新了上面的代码。 但是,当我旋转时,会更新集合视图,但是单元格仍然保持纵向宽度设备的大小。 我添加了屏幕截图。
谁能指出我正确的方向,因为invalidateLayout()在流布局上不起作用。
提前致谢
问题是在创建集合时给集合一个框架使其即使旋转后也能保持它,您可以尝试使用autoLayout
self.view.addSubview(homeCollectionView)
homeCollectionView.translatesAutoresizingMaskIntoConstraints = false
homeCollectionView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
homeCollectionView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
homeCollectionView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
homeCollectionView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
您也可以不使用自动布局来实现这一点,视图控制器通过viewWillLayoutSubviews
或viewDidLayoutSubviews
告诉您其视图何时获得新帧(例如旋转时),这是设置所有与帧/位置相关的属性的好地方。
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
homeCollectionView.frame = view.frame
// Set frames of other views that may have change
}
对于该单元格有override layoutSubviews()
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