ios - 使用 Swift 且不使用 AutoLayout 时，UITableView 高度有时动态不正确

Question

确实，我有一个关于设置 UITableView 高度动态正确的问题。我没有使用自动布局。第一次加载表格时，它包含单元格顶部和底部的大量空间，有时图像与其他单元格重叠。由于图像(图像的高度可能很大)，我无法计算单元格的正确高度，下面是代码。

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

      return cellHeight
}


func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

       let cell:Templategt4 = tableView.dequeueReusableCell(withIdentifier: "Templategt4Identify", for: indexPath) as! Templategt4
        cell.delegate = self;
        cell.configure( self.storyData[0], row: indexPath, screenSize: screenSize,
                        gt4tableview: self.storyTableView);
        //self.secondWebViewLable.scrollView.contentSize.height
       cellHeight = cell.firstWebViewLable.frame.height  + cell.firstImage.frame.height + cell.secondWebViewLable.frame.height;

        //cellHeight = cellHeight + 200

        print("cellForRowAt cellHeight", cellHeight);

        return cell
      }

我正在使用自定义单元格。该单元格包含 UiWebView、UIImageView(高度可能太长)。下面是cell的代码。

class Templategt4: UITableViewCell, UIWebViewDelegate{

@IBOutlet weak var firstWebViewLable: UIWebView!
@IBOutlet weak var firstImage: UIImageView!
@IBOutlet weak var secondWebViewLable: UIWebView!
@IBOutlet weak var playiconimage: UIImageView!
let padding = 24;
var contentHeights1 : [CGFloat] = [0.0]
var contentHeights2 : [CGFloat] = [0.0]
var imageHeights : [CGFloat] = [0.0]
var gt4tableview: UITableView? = nil
var indexpath: IndexPath? = nil
var delegate:ImageClickedForStoryDetails?

class MyTapGestureRecognizer: UITapGestureRecognizer {
    var youTubeCode: String?
}

func configure(_ data: StoryDetailsRequest, row: IndexPath, screenSize: CGRect, gt4tableview: UITableView) {
    self.gt4tableview = gt4tableview;
    self.indexpath = row;
    let callData = data.content[(row as NSIndexPath).row];
    let url = Constants.TEMP_IMAGE_API_URL + callData.image;

        // this is first webview data.
        self.firstWebViewLable.frame.size.height = 1
        self.firstWebViewLable.frame.size = firstWebViewLable.sizeThatFits(.zero)
        let htmlString1:String! = callData.text1
        self.firstWebViewLable.delegate = self;
        self.firstWebViewLable.loadHTMLString(htmlString1, baseURL: nil)
        // this is second webview data.

        self.secondWebViewLable.frame.size.height = 1
        self.secondWebViewLable.frame.size = secondWebViewLable.sizeThatFits(.zero)
        let htmlString2:String! = callData.text2
        self.secondWebViewLable.loadHTMLString(htmlString2, baseURL: nil)
        self.secondWebViewLable.delegate = self;

        if( !callData.image.isEmpty ) {

            let range = url.range(of: "?", options: .backwards)?.lowerBound
            var u:URL!
            if(url.contains("?")) {
                u = URL(string: url.substring(to: range!))
            } else {
                 u = URL(string: url)
            }
            self.firstImage.image = nil
            self.firstImage.kf.setImage(with: u, placeholder: nil,
                                        options: nil, progressBlock: nil, completionHandler: { image, error, cacheType, imageURL in
                                            if( image != nil) {
                                                let imageW = (image?.size.width)!;
                                                let imageheight = (image?.size.height)!;

                                                self.firstImage.image = image;
                                                self.firstImage.contentMode = UIViewContentMode.scaleAspectFit
                                                self.firstImage.clipsToBounds = false

                                                let ratio = self.firstImage.frame.size.width/imageW;

                                                let scaledHeight = imageheight * ratio;
                                                if(scaledHeight < imageheight)
                                                {
                                                    //update height of your imageView frame with scaledHeight
                                                    self.firstImage.frame  = CGRect(x: 0,
                                                                                    y: Int(self.firstWebViewLable.frame.origin.y + self.firstWebViewLable.frame.height),
                                                                                    width: Int(screenSize.width)-self.padding,
                                                                                    height: Int(scaledHeight) )

                                                } else {
                                                    self.firstImage.frame  = CGRect(x: 0,
                                                                                    y: Int(self.firstWebViewLable.frame.origin.y + self.firstWebViewLable.frame.height),
                                                                                    width: Int(screenSize.width)-self.padding,
                                                                                    height: Int(imageheight) )
                                                }
                                            } else {
                                                self.firstImage.image = UIImage(named: "defaultimg")
                                            }


                                            self.secondWebViewLable.frame = CGRect(x: 0,
                                                                                   y: Int(self.firstImage.frame.origin.y + self.firstImage.frame.height),
                                                                                   width: Int(screenSize.width)-self.padding,
                                                                                   height: Int(self.secondWebViewLable.frame.height) )

                                            if (self.imageHeights[0] == 0.0)
                                            {
                                                self.imageHeights[0] = self.firstImage.frame.height

                                                UIView.performWithoutAnimation {
                                                    let ipath = IndexPath(item: (self.indexpath?.row)!, section: (self.indexpath?.section)!)
                                                    self.gt4tableview?.reloadRows(at: [ipath], with: UITableViewRowAnimation.none)
                                                }
                                            }


            })




        }

}

func webViewDidStartLoad(_ webView: UIWebView)
{
    //myActivityIndicator.startAnimating()
}

func webViewDidFinishLoad(_ webView: UIWebView)
{
    if(webView == self.firstWebViewLable) {

        if (contentHeights1[0] != 0.0)
        {
            // we already know height, no need to reload cell
            return
        }
        contentHeights1[0] = self.firstWebViewLable.scrollView.contentSize.height
        UIView.performWithoutAnimation {
            let ipath = IndexPath(item: (self.indexpath?.row)!, section: (self.indexpath?.section)!)
            self.gt4tableview?.reloadRows(at: [ipath], with: UITableViewRowAnimation.none)
        }


    } else if(webView == self.secondWebViewLable) {

        if (contentHeights2[0] != 0.0)
        {
            // we already know height, no need to reload cell
            return
        }

        contentHeights2[0] = self.secondWebViewLable.scrollView.contentSize.height
        UIView.performWithoutAnimation {
            let ipath = IndexPath(item: (self.indexpath?.row)!, section: (self.indexpath?.section)!)
               self.gt4tableview?.reloadRows(at: [ipath], with:UITableViewRowAnimation.none)
        }

    }

}

Answer 1

您不应在 cellForRow 方法中计算单元高度。并使用此方法代替 heightForRowAt:

TableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat

并在您的viewDidLoad中调用它。

tableView.rowHeight = UITableViewAutomaticDimension