我目前有一个UILabel:
factLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 100, 280, 100)];
factLabel.text = @"some text some text some text some text";
factLabel.backgroundColor = [UIColor clearColor];
factLabel.lineBreakMode = UILineBreakModeWordWrap;
factLabel.numberOfLines = 10;
[self.view addSubview:factLabel];
在我的iOS应用程序的整个生命周期中，factLabel获得了许多不同的值。有的句子很多，有的只有5到6个单词。
我如何设置UILabel，使字体大小的变化，使文本总是适合我定义的界限?
当前回答
下面是一个UILabel子类的填充代码，它实现了动画字体大小的改变:
@interface SNTextLayer : CATextLayer
@end
@implementation SNTextLayer
- (void)drawInContext:(CGContextRef)ctx {
// We override this to make text appear at the same vertical positon as in UILabel
// (otherwise it's shifted tdown)
CGFloat height = self.bounds.size.height;
float fontSize = self.fontSize;
// May need to adjust this somewhat if it's not aligned perfectly in your implementation
float yDiff = (height-fontSize)/2 - fontSize/10;
CGContextSaveGState(ctx);
CGContextTranslateCTM(ctx, 0.0, yDiff);
[super drawInContext:ctx];
CGContextRestoreGState(ctx);
}
@end
@interface SNAnimatableLabel ()
@property CATextLayer* textLayer;
@end
@interface SNAnimatableLabel : UILabel
- (void)animateFontToSize:(CGFloat)fontSize withDuration:(double)duration;
@end
@implementation SNAnimatableLabel
- (void)awakeFromNib {
[super awakeFromNib];
_textLayer = [SNTextLayer new];
_textLayer.backgroundColor = self.backgroundColor.CGColor;
_textLayer.foregroundColor = self.textColor.CGColor;
_textLayer.font = CGFontCreateWithFontName((CFStringRef)self.font.fontName);
_textLayer.frame = self.bounds;
_textLayer.string = self.text;
_textLayer.fontSize = self.font.pointSize;
_textLayer.contentsScale = [UIScreen mainScreen].scale;
[_textLayer setPosition: CGPointMake(CGRectGetMidX(_textLayer.frame), CGRectGetMidY(_textLayer.frame))];
[_textLayer setAnchorPoint: CGPointMake(0.5, 0.5)];
[_textLayer setAlignmentMode: kCAAlignmentCenter];
self.textColor = self.backgroundColor;
// Blend text with background, so that it doens't interfere with textlayer text
[self.layer addSublayer:_textLayer];
self.layer.masksToBounds = NO;
}
- (void)setText:(NSString *)text {
_textLayer.string = text;
super.text = text;
}
- (void)layoutSubviews {
[super layoutSubviews];
// Need to enlarge the frame, otherwise the text may get clipped for bigger font sizes
_textLayer.frame = CGRectInset(self.bounds, -5, -5);
}
- (void)animateFontToSize:(CGFloat)fontSize withDuration:(double)duration {
[CATransaction begin];
[CATransaction setAnimationDuration:duration];
_textLayer.fontSize = fontSize;
[CATransaction commit];
}
其他回答
斯威夫特版本:
textLabel.adjustsFontSizeToFitWidth = true
textLabel.minimumScaleFactor = 0.5
这是一个快速扩展UILabel。它运行一个二进制搜索算法，根据标签边界的宽度和高度调整字体大小。测试工作与iOS 9和自动布局。
用法:<label>是预定义的需要调整字体大小的UILabel
<label>.fitFontForSize()
默认情况下，该函数在5pt和300pt的字体大小范围内搜索，并将字体设置为“完全”适合其文本的范围(精确到1.0pt)。你可以定义参数，这样，例如，它在1pt和标签当前字体大小之间精确搜索0.1pts，如下所示:
<label>.fitFontForSize(1.0, maxFontSize: <label>.font.pointSize, accuracy:0.1)
复制/粘贴以下代码到您的文件中
extension UILabel {
func fitFontForSize(var minFontSize : CGFloat = 5.0, var maxFontSize : CGFloat = 300.0, accuracy : CGFloat = 1.0) {
assert(maxFontSize > minFontSize)
layoutIfNeeded() // Can be removed at your own discretion
let constrainedSize = bounds.size
while maxFontSize - minFontSize > accuracy {
let midFontSize : CGFloat = ((minFontSize + maxFontSize) / 2)
font = font.fontWithSize(midFontSize)
sizeToFit()
let checkSize : CGSize = bounds.size
if checkSize.height < constrainedSize.height && checkSize.width < constrainedSize.width {
minFontSize = midFontSize
} else {
maxFontSize = midFontSize
}
}
font = font.fontWithSize(minFontSize)
sizeToFit()
layoutIfNeeded() // Can be removed at your own discretion
}
}
注意:每个layoutIfNeeded()调用都可以自行删除
Swift 2.0版本:
private func adapteSizeLabel(label: UILabel, sizeMax: CGFloat) {
label.numberOfLines = 0
label.lineBreakMode = NSLineBreakMode.ByWordWrapping
let maximumLabelSize = CGSizeMake(label.frame.size.width, sizeMax);
let expectSize = label.sizeThatFits(maximumLabelSize)
label.frame = CGRectMake(label.frame.origin.x, label.frame.origin.y, expectSize.width, expectSize.height)
}
只需要发送sizeToFit消息到UITextView。它会调整自己的高度以适应文本。它不会改变自己的宽度或原点。
[textViewA1 sizeToFit];
minimumFontSize在iOS 6中已弃用。你可以使用minimumScaleFactor。
yourLabel.adjustsFontSizeToFitWidth=YES;
yourLabel.minimumScaleFactor=0.5;
这将照顾你的字体大小根据标签和文本的宽度。
