在c#中，这在UITableViewCell中为我工作。

        UILabel myLabel = new UILabel();
        myLabel.Font = UIFont.SystemFontOfSize(16);
        myLabel.Lines = 0;
        myLabel.TextAlignment = UITextAlignment.Left;
        myLabel.LineBreakMode = UILineBreakMode.WordWrap;
        myLabel.MinimumScaleFactor = 1;
        myLabel.AdjustsFontSizeToFitWidth = true;

       myLabel.InvalidateIntrinsicContentSize();
       myLabel.Frame = new CoreGraphics.CGRect(20, mycell.ContentView.Frame.Y + 20, cell.ContentView.Frame.Size.Width - 40, mycell.ContentView.Frame.Size.Height);
       myCell.ContentView.AddSubview(myLabel);

我认为这里的重点是:-

            myLabel.TextAlignment = UITextAlignment.Left;
            myLabel.LineBreakMode = UILineBreakMode.WordWrap;
            myLabel.MinimumScaleFactor = 1;
            myLabel.AdjustsFontSizeToFitWidth = true;

让我们试试这个

textLabel.lineBreakMode = NSLineBreakModeWordWrap; // UILineBreakModeWordWrap deprecated     
textLabel.numberOfLines = 0;                          

当使用NSString填充UILabel时，您可以使用\r转到下一行。

UILabel * label;


label.text = [NSString stringWithFormat:@"%@ \r %@",@"first line",@"seconcd line"];

UILabel *labelName = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 30)];
[labelName sizeToFit];
labelName.numberOfLines = 0;
labelName.text = @"Your String...";
[self.view addSubview:labelName];

斯威夫特4:

label.lineBreakMode = .byWordWrapping

label.numberOfLines = 0

label.translatesAutoresizingMaskIntoConstraints = false

label.preferredMaxLayoutWidth = superview.bounds.size.width - 10 

UILabel *helpLabel = [[UILabel alloc] init];
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:label];
helpLabel.attributedText = attrString;
// helpLabel.text = label;

helpLabel.textAlignment = NSTextAlignmentCenter;
helpLabel.lineBreakMode = NSLineBreakByWordWrapping;
helpLabel.numberOfLines = 0;

出于某些原因，它在iOS 6中不为我工作，不知道为什么。尝试了带和不带带属性的文本。任何建议。