Question

如果文本太长，我会建立一个视图，其中显示很多文本，并且需要向下滚动。向下滚动时，我可以看到垂直滚动条在移动，但是视图没有变化。不使用功能scrollViewWillBeginDragging和scrollViewDidScroll（在控制台中什么也没有发生）。我还使用了isScrollEnabled = true，但是它不起作用。我想念什么吗？

import UIKit
//

class TestView : UIScrollView{

    var testObject: TestObject? {
        didSet {
            //set texts
            ....
            //set height for textViews depending on text
            refreshHeightOfTextViews()
        }
    }

    lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.backgroundColor = UIColor.white
        cv.translatesAutoresizingMaskIntoConstraints = false
        return cv
    }()

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
        isScrollEnabled = true
        contentSize = CGSize(width: self.frame.width, height: 2000)
    }

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


    var dateFormatter = DateFormatter()

    let dateLabel : UILabel = {
        let label = UILabel()
        label.text = "Date:"
        label.font = UIFont(name: (label.font?.fontName)!, size: 20)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let testALabel : UILabel = {
        let label = UILabel()
        label.text = "TestA:"
        label.font = UIFont(name: (label.font?.fontName)!, size: 20)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let testBLabel : UILabel = {
        let label = UILabel()
        label.text = "TestB:"
        label.font = UIFont(name: (label.font?.fontName)!, size: 20)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let testCLabel : UILabel = {
        let label = UILabel()
        label.text = "TestC:"
        label.font = UIFont(name: (label.font?.fontName)!, size: 20)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let testDLabel : UILabel = {
        let label = UILabel()
        label.text = "TestD:"
        label.font = UIFont(name: (label.font?.fontName)!, size: 20)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let contentLabel : UILabel = {
        let label = UILabel()
        label.text = "Content:"
        label.font = UIFont(name: (label.font?.fontName)!, size: 20)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let contentValueTextView : UITextView = {
        let textView = UITextView()
        textView.text = "A"
        textView.textContainerInset = UIEdgeInsetsMake(0, -4, 0, 0)
        textView.font = UIFont(name: (textView.font?.fontName)!, size: 20)
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.isEditable = false
//        textView.backgroundColor = UIColor.red
        textView.isScrollEnabled = false
        return textView
    }()

    func setupViews() {
        backgroundColor = UIColor.white

        addSubview(dateLabel)
        addSubview(testALabel)
        addSubview(testBLabel)
        addSubview(testCLabel)
        addSubview(testDLabel)
        addSubview(contentLabel)
        addSubview(contentValueTextView)

        setupLabels()
    }

    func refreshHeightOfTextViews() {
        let contentSize = CGSize(width: self.frame.width, height: .infinity)
        let estimatedContentSize = contentValueTextView.sizeThatFits(contentSize)
        contentValueTextView.heightAnchor.constraint(equalToConstant: estimatedContentSize.height).isActive = true
    }

    func setupLabels() {
        dateFormatter.dateFormat = "dd.MM.yyyy"
        dateLabel.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
        dateLabel.topAnchor.constraint(equalTo: self.safeAreaLayoutGuide.topAnchor).isActive = true
        dateLabel.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
        dateLabel.heightAnchor.constraint(equalToConstant: 24).isActive = true

        testALabel.leftAnchor.constraint(equalTo: dateLabel.leftAnchor).isActive = true
        testALabel.topAnchor.constraint(equalTo: dateLabel.bottomAnchor).isActive = true
        testALabel.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
        testALabel.heightAnchor.constraint(equalTo: dateLabel.heightAnchor).isActive = true

        testBLabel.leftAnchor.constraint(equalTo: testALabel.leftAnchor).isActive = true
        testBLabel.topAnchor.constraint(equalTo: testALabel.bottomAnchor).isActive = true
        testBLabel.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
        testBLabel.heightAnchor.constraint(equalTo: dateLabel.heightAnchor).isActive = true

        testCLabel.leftAnchor.constraint(equalTo: testBLabel.leftAnchor).isActive = true
        testCLabel.topAnchor.constraint(equalTo: testBLabel.bottomAnchor).isActive = true
        testCLabel.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
        testCLabel.heightAnchor.constraint(equalTo: dateLabel.heightAnchor).isActive = true

        testDLabel.leftAnchor.constraint(equalTo: testCLabel.leftAnchor).isActive = true
        testDLabel.topAnchor.constraint(equalTo: testCLabel.bottomAnchor).isActive = true
        testDLabel.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
        testDLabel.heightAnchor.constraint(equalTo: dateLabel.heightAnchor).isActive = true

        contentLabel.leftAnchor.constraint(equalTo: testDLabel.leftAnchor).isActive = true
        contentLabel.topAnchor.constraint(equalTo: testDLabel.bottomAnchor).isActive = true
        contentLabel.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true

        contentValueTextView.leftAnchor.constraint(equalTo: contentLabel.leftAnchor).isActive = true
        contentValueTextView.topAnchor.constraint(equalTo: contentLabel.bottomAnchor).isActive = true
        contentValueTextView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true            
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        print("\(scrollView.contentOffset.y)")
    }

    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
        print("test")
    }

}


class TestController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    var testObject: TestObject? 

    override func viewDidLoad() {
        super.viewDidLoad()

        let testFrame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height)
        let testView = TestView(frame: testFrame)
        testView.testObject = testObject
        view.addSubview(testView)

        testView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        testView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        testView.widthAnchor.constraint(equalToConstant: view.frame.width).isActive = true
        testView.heightAnchor.constraint(equalToConstant: view.frame.height).isActive = true

    }
}

Answer 1

为了使scrollview正确滚动，您需要将所有项目添加到uiView中，并将该uiView添加到scrollView中。新的uiView的高度应设置为大于scrollView的值。除非未明确设置uiScrollView和uiView的高度，否则它也不起作用。您基本上可以明确地告诉您的应用程序，scrollView内部的包含视图大于其自身，因此您应该滚动。

Answer 2

不应通过添加子视图来像UIScrollViews一样使用UICollectionViews。

集合视图的内容由数据源提供的UICollectionViewCells计算。您应将内容分为“集合视图”单元格（或将所有内容放到一个视图中，无论如何）。

另一种选择是创建一个补充视图，该视图也应由数据源提供。

请参阅https://developer.apple.com/documentation/uikit/uicollectionviewdatasource

迅速：UIScrollView中的项目不会滚动

2 个答案: