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?
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];
}
根据@Eyal Ben Dov的回答,你可能想要创建一个类别,以便在你的其他应用中灵活使用。
奥林匹克广播服务公司。:我已经更新了他的代码,使其与iOS 7兼容
筒式水管文件
#import <UIKit/UIKit.h>
@interface UILabel (DynamicFontSize)
-(void) adjustFontSizeToFillItsContents;
@end
实现文件
#import "UILabel+DynamicFontSize.h"
@implementation UILabel (DynamicFontSize)
#define CATEGORY_DYNAMIC_FONT_SIZE_MAXIMUM_VALUE 35
#define CATEGORY_DYNAMIC_FONT_SIZE_MINIMUM_VALUE 3
-(void) adjustFontSizeToFillItsContents
{
NSString* text = self.text;
for (int i = CATEGORY_DYNAMIC_FONT_SIZE_MAXIMUM_VALUE; i>CATEGORY_DYNAMIC_FONT_SIZE_MINIMUM_VALUE; i--) {
UIFont *font = [UIFont fontWithName:self.font.fontName size:(CGFloat)i];
NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:text attributes:@{NSFontAttributeName: font}];
CGRect rectSize = [attributedText boundingRectWithSize:CGSizeMake(self.frame.size.width, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin context:nil];
if (rectSize.size.height <= self.frame.size.height) {
self.font = [UIFont fontWithName:self.font.fontName size:(CGFloat)i];
break;
}
}
}
@end
使用
#import "UILabel+DynamicFontSize.h"
[myUILabel adjustFontSizeToFillItsContents];
干杯