我知道如何将UINavigationBar
中的单个图像居中,但不知道如何使用动态数量的图像来做到这一点。我有一个支持群聊的聊天应用。群聊中的人数可以少至3,但没有上限。
在UINavigationBar
中,我必须设置标题以显示至少4或5个重叠的图像(但不能超过此数目,因为在UINavigationBar
中看起来很奇怪)和{{1} }显示在同一群聊中有多少用户(即UILabel
)。标题(所有图像和标签)应位于+ 15 more
的中心。正在从服务器下载图像。
当用户点击标题(UINavigationBar
中的任何图像或标签)时,它应该触发一个动作,以在单独的UINavigationBar
叠加图像的数量是动态的(基于每次群聊),但是我不知道该怎么做。这是最终结果的图像:
有人曾做过此事还是有一个如何实现此目的的想法?非常感谢帮助
更新:
我尝试使用UIViewController
完成此操作,但是我遇到了多个问题。这是代码:
UIStackView
答案 0 :(得分:0)
我不确定stackView。但是对于一个简单的实现,我使用了collectionView。检查以下策略。您应该能够根据需要进行相应的修改。
import UIKit
class OverlayCell: UICollectionViewCell {
func didplay(with number: String) {
let view = UIView(frame: CGRect(x: 0, y: 0, width: 40.0, height: 40.0))
view.backgroundColor = UIColor.blue
view.layer.cornerRadius = 20.0
view.layer.masksToBounds = true
view.layer.borderColor = UIColor.white.cgColor
view.layer.borderWidth = 2.0
let label = UILabel(frame: CGRect(x: 2, y: 2, width: view.bounds.width - 4, height: view.bounds.height - 4))
label.textColor = .white
label.text = number
label.textAlignment = .center
view.addSubview(label)
contentView.addSubview(view)
contentView.transform = CGAffineTransform(scaleX: -1, y: 1)
}
}
class OverlayedView: UIView {
var mainView: UIView!
var imageCollection: UICollectionView!
//Static for now
let cellWidth: CGFloat = 40.0
let cellHeight: CGFloat = 40.0
var collectionWidth: CGFloat = 115.0
override init(frame: CGRect) {
super.init(frame: frame)
loadNib()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
loadNib()
}
private func loadNib() {
if let view = Bundle.main.loadNibNamed("OverlayedView", owner: self, options: nil)?.first as? UIView {
mainView = view
mainView.frame = self.bounds
self.backgroundColor = .black
addSubview(view)
}
}
var dataSource = ["4","3","2","1"]
func loadData() {
//dynamically calculate collectionWidth to be able to kepp it in center
collectionWidth = dataSource.count >= 4 ? CGFloat(dataSource.count) * cellWidth - CGFloat((dataSource.count - 1) * 15) : CGFloat(dataSource.count) * cellWidth - CGFloat((dataSource.count - 1) * 15) //CGFloat(dataSource.count * 15) here is the item spacing from delegate -15 inward so that we can get overlapping effect
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
imageCollection = UICollectionView(frame: CGRect(x: 0, y: 0, width: collectionWidth, height: self.bounds.height), collectionViewLayout: layout)
imageCollection.center = mainView.center
imageCollection.register(OverlayCell.self, forCellWithReuseIdentifier: "Cell")
//flip the collectionView so that it loads from right to left for overlapping effect
imageCollection.transform = CGAffineTransform(scaleX: -1, y: 1)
imageCollection.delegate = self
imageCollection.dataSource = self
mainView.addSubview(imageCollection)
}
}
extension OverlayedView: UICollectionViewDelegate, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if dataSource.count > 4 {
return 4
}
return dataSource.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! OverlayCell
cell.didplay(with: dataSource[indexPath.row])
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let size = CGSize(width: 40.0 , height: 40.0)
return size
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0.0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return -15.0
}
}
用法:
let navOverlay = OverlayedView(frame: CGRect(x: 0, y: 0, width: 250.0, height: 44.0))
navOverlay.loadData() . //pass your data to this method
navigationItem.titleView = navOverlay
答案 1 :(得分:0)
我终于知道了。不确定这是否是实现它的正确方法,但是这是实现它的方法,并且效果很好。注意事项-我必须根据我们拥有的图像数来计算navStackView
宽度。超过5-6张图像过于模糊,因此,不超过5张图像。
navStackView.spacing
也是根据图像之间的宽度和所需空间来计算的。
var navStackView : UIStackView = {
let stack = UIStackView()
stack.axis = .horizontal
stack.alignment = .fill
stack.distribution = .fillEqually
stack.translatesAutoresizingMaskIntoConstraints = false
return stack
}()
var moreLabel: UILabel = {
let label = UILabel()
label.text = "+ 5 more"
label.textColor = .black
label.textAlignment = .left
label.translatesAutoresizingMaskIntoConstraints = false
return label
}()
var images = ["1", "2", "3", "4", "3", "3"]
override func viewDidLoad() {
super.viewDidLoad()
let navController = navigationController!
navController.navigationBar.addSubview(navStackView)
// x, y, w, h
navStackView.widthAnchor.constraint(equalToConstant: 95).isActive = true
navStackView.centerYAnchor.constraint(equalTo: navController.navigationBar.centerYAnchor).isActive = true
navStackView.heightAnchor.constraint(equalToConstant: 35).isActive = true
navStackView.centerXAnchor.constraint(equalTo: navController.navigationBar.centerXAnchor).isActive = true
// image height = 35, image width = 35
// when subtracting spacing from NavStackView, we need to subtrack from the width as well for (items - 1)
switch images.count {
case 0:
print("0 images")
case 1:
changeNavStackWidth(constant: 60, spacing: 0)
moreLabel.isHidden = true
case 2:
changeNavStackWidth(constant: 80, spacing: 10)
moreLabel.isHidden = true
case 3:
changeNavStackWidth(constant: 95, spacing: -5)
moreLabel.isHidden = true
case 4:
changeNavStackWidth(constant: 110, spacing: -10)
moreLabel.isHidden = true
case 5:
changeNavStackWidth(constant: 95, spacing: -20)
moreLabel.isHidden = true
case 6...1000:
changeNavStackWidth(constant: 95, spacing: -20)
moreLabel.isHidden = false
default:
print("default")
}
for image in images {
let imageView = UIImageView()
imageView.image = UIImage(named: image)
imageView.layer.borderColor = UIColor.white.cgColor
imageView.layer.borderWidth = 1
imageView.contentMode = .scaleAspectFill
imageView.clipsToBounds = true
navStackView.addArrangedSubview(imageView)
navStackView.layoutIfNeeded()
}
navController.navigationBar.addSubview(moreLabel)
// x, y ,w, h
moreLabel.leadingAnchor.constraint(equalTo: navStackView.trailingAnchor, constant: 50).isActive = true
moreLabel.topAnchor.constraint(equalTo: navStackView.topAnchor).isActive = true
moreLabel.bottomAnchor.constraint(equalTo: navStackView.bottomAnchor).isActive = true
navigationItem.titleView = navStackView
let stackTap = UITapGestureRecognizer()
stackTap.addTarget(self, action: #selector(stackTapped))
navStackView.isUserInteractionEnabled = true
navStackView.addGestureRecognizer(stackTap)
}
@objc func stackTapped() {
print("tapp")
}
func changeNavStackWidth(constant: CGFloat, spacing: CGFloat) {
navStackView.constraints.forEach { constraint in
if constraint.firstAttribute == .width {
constraint.constant = constant
}
}
navStackView.spacing = spacing
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
navStackView.subviews.forEach { $0.layer.cornerRadius = $0.frame.height / 2 }
}