我希望有一个标签能够有多行，最小字体大小，并在父视图中水平和垂直居中。我以编程方式将标签添加到视图中：

- (void) customInit {
    // Setup label
    self.label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
    self.label.numberOfLines = 0;
    self.label.lineBreakMode = UILineBreakModeWordWrap;
    self.label.textAlignment = UITextAlignmentCenter;

    // Add the label as a subview
    self.autoresizesSubviews = YES;
    [self addSubview:self.label];
}

然后当我想更改标签的文本时。。。

- (void) updateDisplay:(NSString *)text {
    if (![text isEqualToString:self.label.text]) {
        // Calculate the font size to use (save to label's font)
        CGSize textConstrainedSize = CGSizeMake(self.frame.size.width, INT_MAX);
        self.label.font = [UIFont systemFontOfSize:TICKER_FONT_SIZE];
        CGSize textSize = [text sizeWithFont:self.label.font constrainedToSize:textConstrainedSize];
        while (textSize.height > self.frame.size.height && self.label.font.pointSize > TICKER_MINIMUM_FONT_SIZE) {
            self.label.font = [UIFont systemFontOfSize:self.label.font.pointSize-1];
            textSize = [ticker.blurb sizeWithFont:self.label.font constrainedToSize:textConstrainedSize];
        }
        // In cases where the frame is still too large (when we're exceeding minimum font size),
        // use the views size
        if (textSize.height > self.frame.size.height) {
            textSize = [text sizeWithFont:self.label.font constrainedToSize:self.frame.size];
        }

        // Draw 
        self.label.frame = CGRectMake(0, self.frame.size.height/2 - textSize.height/2, self.frame.size.width, textSize.height);
        self.label.text = text;
    }
    [self setNeedsDisplay];
}

希望这对某人有所帮助！

快速用户界面

在SwiftUI中，所有视图的大小通常为适合其内容的大小，但如果明确使用框架修饰符，则可以使用框架的对齐参数：

Text("Text")
    .background(Color.red)
    .frame(width: 100, height: 200, alignment: .top)

此外，如果使用任何类型的“堆栈”来排列视图，所有视图都有一个类似于框架的参数，称为对齐：

ZStack(alignment: .top) {
    Color.red
    Text("Text")
        .background(Color.red)
}

您可以使用TTTAttributedLabel，它支持垂直对齐。

@property (nonatomic) TTTAttributedLabel* label;
<...>

//view's or viewController's init method
_label.verticalAlignment = TTTAttributedLabelVerticalAlignmentTop;

此代码帮助您使文本与顶部对齐，并使标签高度与文本内容固定。

使用以下代码的说明

默认情况下，isHeightToChange会自动将标签的高度设置为与文本内容相同。isHeightToChange如果为false，则使文本对齐到顶部，而不降低标签的高度。

#import "DynamicHeightLable.h"

@implementation DynamicHeightLable
@synthesize isHeightToChange;
- (id)initWithFrame:(CGRect)frame 
{
    self = [super initWithFrame:frame];
    if (self)
    {
        // Initialization code.
        self.isHeightToChange=FALSE;//default

    }
    return self;
}
- (void)drawTextInRect:(CGRect)rect
{
    if(!isHeightToChange){
    CGSize maximumLabelSize = CGSizeMake(self.frame.size.width,2500);

    CGFloat height = [self.text sizeWithFont:self.font
                           constrainedToSize:maximumLabelSize
                               lineBreakMode:self.lineBreakMode].height;
    if (self.numberOfLines != 0) {
        height = MIN(height, self.font.lineHeight * self.numberOfLines);
    }
    rect.size.height = MIN(rect.size.height, height);
    }
    [super drawTextInRect:rect];

}
- (void) layoutSubviews
{
    [super layoutSubviews];
       if(isHeightToChange){
     CGRect ltempFrame = self.frame;
    CGSize maximumLabelSize = CGSizeMake(self.frame.size.width,2500);

    CGFloat height = [self.text sizeWithFont:self.font
                           constrainedToSize:maximumLabelSize
                               lineBreakMode:self.lineBreakMode].height;
    if (self.numberOfLines != 0) {
        height = MIN(height, self.font.lineHeight * self.numberOfLines);
    }
    ltempFrame.size.height = MIN(ltempFrame.size.height, height);

    ltempFrame.size.height=ltempFrame.size.height;
    self.frame=ltempFrame;
       }
}
@end

试试这个！！太手动了，但对我来说很完美。

[labelName setText:@"This is just a demo"];

NSMutableString *yourString1= @"This is just a demo";


// breaking string
labelName.lineBreakMode=UILineBreakModeTailTruncation;
labelName.numberOfLines = 3;


CGSize maximumLabelSize1 = CGSizeMake(276,37); // Your Maximum text size

CGSize expectedLabelSize1 = [yourString1 sizeWithFont:labelName.font
                                    constrainedToSize:maximumLabelSize1
                                        lineBreakMode:labelName.lineBreakMode];

[labelName setText:yourString1];


CGRect newFrame1 = labelName.frame;
if (expectedLabelSize1.height>=10)
{
    newFrame1.size.height = expectedLabelSize1.height;
}

labelName.frame = newFrame1;

如果可以选择创建自己的自定义视图，可以执行以下操作：

- (void)drawRect:(CGRect)rect
{
    CGRect bounds = self.bounds;
    [self.textColor set];
    [self.text drawInRect:bounds
                 withFont:self.font
            lineBreakMode:UILineBreakModeTailTruncation
                alignment:self.textAlignment];
}