iOS 7的動態表視圖單元格高度

Question

我有一個包含tableview的視圖控制器。 表視圖由包含單個標簽的自定義單元格組成。 我有不同長度的文本，將在這些單元格中顯示。 我面臨的問題是，細胞沒有擴展到適當的高度。 我在SO中嘗試了很多解決方案，但到目前為止它們都沒有。 這是視圖控制器的代碼

class ViewController: UIViewController {

    @IBOutlet var tableView: UITableView!

    let items = [
        "This is the first text",
        "This is the first text and this is the second text","now you may be thinking where is the third text?. Well, There was the first text and second text, now here is the third text",
        "This is the fourth short and sweet text",
        "Slow down you crazy child, you're so ambitious for a juvenile. If you're so smart, tell me why are you still so afraid.","Where's the fire? What's the hurry about. You better cool it off before you burn it out. There's so much to do and so many hours in a day.You got your passion, got your pride. Don't you know that only fools are satisfied. Dream on but don't imagine that they come true. Don't even realise vienna waits for you"]

    var prototypeCell:CustomCell!

    override func viewDidLoad() {
        super.viewDidLoad()

        //setting up tableview
        self.tableView.allowsSelection = false
        self.tableView.dataSource = self
        self.tableView.delegate = self

        configurePrototypeCell()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func configureCell(cell:CustomCell, forIndexPath indexPath:NSIndexPath)
    {
        cell.itemLabel.text = items[indexPath.row]

    }


    func configurePrototypeCell()
    {
        self.prototypeCell = self.tableView.dequeueReusableCellWithIdentifier("Cell") as! CustomCell
    }


}

extension ViewController:UITableViewDataSource
{
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! CustomCell
        configureCell(cell, forIndexPath: indexPath)
        return cell

    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
}

extension ViewController: UITableViewDelegate
{

    func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

        self.prototypeCell.itemLabel.text = items[indexPath.row]
        self.prototypeCell.itemLabel.preferredMaxLayoutWidth = CGRectGetWidth(self.tableView.frame)

        self.prototypeCell.setNeedsLayout()
        self.prototypeCell.layoutIfNeeded()


        let size = self.prototypeCell.contentView.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize)
        let height = size.height
        return height


    }

    func tableView(tableView: UITableView, estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        return UITableViewAutomaticDimension
    }

}

CustomCell類是UITableViewCell子類。 它包含名為itemLabel的UILabel 。

Answer 1

請在自定義單元格中嘗試此操作，從TableviewDelegate高度方法調用此方法來計算自定義單元格高度。

碼：
let size = sizingCell.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize)

Answer 2

override func viewDidLoad() {
    super.viewDidLoad()
    tableView.estimatedRowHeight = 40;
    tableView.rowHeight = UITableViewAutomaticDimension;
}

這需要啟用Autolayout並正確設置約束。

Answer 3

在這里，我在Objective-C中編寫代碼，但您可以在swift中輕松修改它。

1）首先設置標簽的約束，如下所示：

2）在customCell.m文件中實現以下方法

- (CGFloat)requiredHeight
{
    CGSize size = [self.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    NSLog(@"Size :%@",NSStringFromCGSize(size));
    CGFloat minimumHeight = 40.0f; //cell height which you have taken in xib
    if (size.height < minimumHeight)
    {
        return minimumHeight;
    }
    return size.height;
}

3）在cellForRow和HeightForRow方法中進行一些更改，如下所示：

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    cell.itemLabel.preferredMaxLayoutWidth = tableView.bounds.size.width -36; //Here 36 indicates Leading and Trailing distance of label which you have put in xib
    [cell.itemLabel updateConstraintsIfNeeded];

    return cell;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{

     return [viewAllCell requiredHeight]+[self calculateLabelHeightforText:viewAllCell.Lblname.text andFonts:viewAllCell.Lblname.font andWidth:viewAllCell.Lblname.frame.size.width]-default label height; //
}
-(float)calculateLabelHeightforText:(NSString *)text andFonts:(UIFont *)font andWidth:(float)width
{
    if (text==nil) {
        return 40; //default height
    }
    NSAttributedString *attributedText = [[NSAttributedString alloc]initWithString:text attributes:@{NSFontAttributeName:font}]
    ;
    CGRect rect = [attributedText boundingRectWithSize:(CGSize){width, CGFLOAT_MAX}
                                               options:NSStringDrawingUsesLineFragmentOrigin
                                               context:nil];
    return rect.size.height+4;
}

4）在viewDidLoad中進行一些更改：

- (void)viewDidLoad {
 [super viewDidLoad];
 self.TblDetail.rowHeight = UITableViewAutomaticDimension;
  self.TblDetail.estimatedRowHeight = 40.0;
}

Answer 4

試試這個代碼，它適合我，

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

            let str : String! = items[indexPath.row]

            let boundingRect = str.boundingRectWithSize(CGSizeMake(tableView.frame.size.width - 100, CGFloat.max),
                options:NSStringDrawingOptions.UsesLineFragmentOrigin,
                attributes: [NSFontAttributeName: UIFont(name: "Arial", size: 14.0)!], context:nil).size.height + 45.0

            if(boundingRect > 95.0) {
                return boundingRect
            } else {
                return 95
            }

    }

如果你得到boundingRect值，那么返回它動態改變UITableView的高度，希望它有用