这是我的集合视图单元格的自定义类:
import UIKit
class NavBarCell: UICollectionViewCell {
var avatarImageView: UIImageView = {
var avatarView = UIImageView()
avatarView.contentMode = .scaleAspectFit
return avatarView
}()
override init(frame: CGRect) {
super.init(frame: frame)
avatarImageView = UIImageView()
contentView.addSubview(avatarImageView)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
然后在我的控制器的viewDidLoad
中我有
let layout:UICollectionViewFlowLayout = UICollectionViewFlowLayout.init()
navBarCollectionView.setCollectionViewLayout(layout, animated: true)
navBarCollectionView.backgroundColor = UIColor.clear
navBarCollectionView.register(NavBarCell.self, forCellWithReuseIdentifier: "cell")
navBarCollectionView.delegate = self
navBarCollectionView.dataSource = self
layout.scrollDirection = .horizontal
self.navigationController?.navigationBar.addSubview(navBarCollectionView)
navBarCollectionView.reloadData()
在cellForItem
我有:
let navBarCell = (collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)) as! NavBarCell
var image : UIImage = UIImage(named: "TestImage")!
navBarCell.avatarImageView.image = image
navBarCell.avatarImageView.layer.borderWidth = 1
navBarCell.avatarImageView.layer.borderColor = UIColor.getRandomColor().cgColor
navBarCell.avatarImageView.layer.cornerRadius = 20
return navBarCell
但图像视图没有显示出来。如果我添加navBarCell.backgroundColor = UIColor.red
,则单元格会显示,但不显示图像。
我遗失了什么,或者没有正确实施?
答案 0 :(得分:2)
UICollectionViewCell
已经是一个视图,您可以直接向其添加avatarImageView
:
addSubview(avatarImageView)
您还可以设置约束,例如:
avatarImageView.translatesAutoresizingMaskIntoConstraints = false
avatarImageView.topAnchor.constraint(equalTo: topAnchor).isActive = true
avatarImageView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
avatarImageView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
avatarImageView.heightAnchor.constraint(equalToConstant: 300).isActive = true
答案 1 :(得分:0)
最佳做法是创建原型单元格并在界面构建器中添加图像视图。在这种特定情况下,我认为错误在于您没有将图像视图的框架设置为缩放到单元格框架。
尝试打印图像视图的框架,它可能会显示0,0,0,0。