Question

我试图从自定义选项卡栏中显示另一个ViewController，但是，我无法将视图控制器传递给自定义类。

我已经尝试过var jlvc = HomeController（），但这会使应用程序崩溃。

class JournalListViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    override func viewDidLoad() {
        super.viewDidLoad()
        print(self)
        navigationController?.navigationBar.isTranslucent = false

        let titleLabel = UILabel(frame: CGRect(x: 0, y: 0, width: view.frame.width-32, height: view.frame.height))
        titleLabel.textColor = UIColor.white
        titleLabel.text = "Journal List"
        titleLabel.font = UIFont.systemFont(ofSize: 20)
        navigationItem.titleView = titleLabel

        collectionView?.backgroundColor = UIColor.white

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Register cell class
        collectionView?.register(JournalCell.self, forCellWithReuseIdentifier: "cellId")

        // To unblock view from menubar
        collectionView?.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 60, right: 0)
        collectionView?.scrollIndicatorInsets = UIEdgeInsets(top: 0, left: 0, bottom: 60, right: 0)

        // Do any additional setup after loading the view.
        setupMenuBar()
    }

    let menuBar: MenuBar = {
        let mb = MenuBar()
        mb.jlvc = self
        return mb
    }()

    private func setupMenuBar(){
        view.addSubview(menuBar)
        view.addConstraintsWithFormat(format: "H:|[v0]|", views: menuBar)
        view.addConstraintsWithFormat(format: "V:[v0(60)]|", views: menuBar)
    }

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using [segue destinationViewController].
        // Pass the selected object to the new view controller.
    }
    */

    // MARK: UICollectionViewDataSource

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 5
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId", for: indexPath)
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let height = (view.frame.width - 16 - 16) * 9 / 16                  //-16 for top, - 16 for bot, 16/9 aspect ratio so * by 9/16
        return CGSize(width:view.frame.width, height:height + 16 + 41)      //height is height if image + additional space we added
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }

    func showHomeController(){
        let hc = HomeController()
        navigationController?.pushViewController(hc, animated: true)
    }

import Foundation
import UIKit



class MenuBar: UIView, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

    var jlvc: JournalListViewController?

    lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.backgroundColor = UIColor(red: 152/255, green: 216/255, blue: 142/255, alpha: 1)
        cv.dataSource = self
        cv.delegate = self
        return cv
    }()

    let cellId = "cellId"
    let imageNames = ["home","camera","journal"]

    override init(frame: CGRect) {
        super.init(frame: frame)

        collectionView.register(MenuCell.self, forCellWithReuseIdentifier: cellId)

        addSubview(collectionView)
        addConstraintsWithFormat(format: "H:|[v0]|", views: collectionView)
        addConstraintsWithFormat(format: "V:|[v0]|", views: collectionView)

        let selectIndexPath = IndexPath(item: 0, section: 0)
        collectionView.selectItem(at: selectIndexPath, animated: false, scrollPosition: [])
        self.collectionView.isScrollEnabled = false
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }

    // Returning Cell
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId", for: indexPath) as! MenuCell
        cell.imageView.image = UIImage(named: imageNames[indexPath.item])?.withRenderingMode(.alwaysTemplate)
        cell.tintColor = UIColor.black
        cell.jlvc = self.jlvc
        return cell
    }

    // Size of Cell
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: frame.width / 3, height: frame.height)
    }

    // Spaceing in between cells
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }

    // Selecting cell
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath) as! MenuCell
        if cell.imageView.image == UIImage(named: "home")?.withRenderingMode(.alwaysTemplate) {
            jlvc?.showHomeController()
        }

    }


    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

class MenuCell: BaseCell {

    var jlvc: JournalListViewController?

    let imageView: UIImageView = {
        let iv = UIImageView()
        iv.image = UIImage(named: "home")?.withRenderingMode(.alwaysTemplate)
        iv.tintColor = UIColor.black
        return iv
    }()

    override var isHighlighted: Bool {
        didSet{
            imageView.tintColor = isHighlighted ? UIColor.white : UIColor.black
        }
    }

    override var isSelected: Bool {
        didSet{
            imageView.tintColor = isSelected ? UIColor.white : UIColor.black
        }
    }

    override func setupViews() {
        super.setupViews()

        addSubview(imageView)
        addConstraintsWithFormat(format: "H:[v0(28)]", views: imageView)
        addConstraintsWithFormat(format: "V:[v0(28)]", views: imageView)

        addConstraint(NSLayoutConstraint(item: imageView, attribute: .centerX, relatedBy: .equal, toItem: self, attribute: .centerX, multiplier: 1, constant: 0))
        addConstraint(NSLayoutConstraint(item: imageView, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1, constant: 0))
    }

}

无法将类型'（JournalListViewController）->（）-> JournalListViewController'的值分配为'JournalListViewController吗？'

Answer 1

let menuBar: MenuBar = {
    let mb = MenuBar()
    mb.jlvc = self
    return mb
}()

这不符合您的想法。在这种情况下，self是类，而不是实例。您要么将其设为lazy var（就像对collectionView所做的那样），要么将其明确分配。

无法将类型'（JournalListViewController）->（）-> JournalListViewController'的值分配为'JournalListViewController？”

1 个答案: