iOS UILabel 文字竖排显示

编程入门行业动态更新时间:2024-10-04 23:29:04

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iOS UILabel 文字竖排显示

做iOS开发要经常用到UILabel。UILabel一般只适用一些简单的文字显示。当需要复杂的图文混排的时候，可以用CoreText来做。但是CoreText用法复杂，当我们遇到一些不是很复杂的交互需求时，用CoreText就有点杀鸡用牛刀的意思。这里介绍一下我在项目里遇到的一个案例。
先来看看效果：

这里要求文字都是竖排显示，并且当文字是非汉字的时候又要把文字侧过来以方便阅读。
下面就介绍一下我实现这个需求的过程。

一、计算label的高度

在很多场景下，我们需要事先知道这个label的size，下面这个方法可以计算在已知width、font和label中的text内容的情况下，这个label的高度。

1 2 3 4 5 6 - (CGSize)getSize:(NSString *)detail font:(UIFont *)font width:( float )width { CGSize constraint = CGSizeMake(width, 20000 .0f); CGSize size = [detail sizeWithFont:font constrainedToSize:constraint lineBreakMode:UILineBreakModeCharacterWrap]; return size; }

利用这个方法也可以简单的实现竖排显示文字，只需要把width参数设置成一个字符的宽度就可以。一般字体大小在14 – 20之间，width参数设置为14.0

二、如何让label置顶或其它

label默认的textAlignment只有UITextAlignmentLeft、UITextAlignmentCenter、UITextAlignmentRight三种。
在需要文字居顶，居底时，UILabel的api就不够用了。不过这个时候我们可以通过重写UILabel的- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines方法来实现。代码如下：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 - (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines { CGRect textRect = [ super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines]; switch (self.verticalAlignment) { case VerticalAlignmentTop: textRect.origin.y = bounds.origin.y; break ; case VerticalAlignmentBottom: textRect.origin.y = bounds.origin.y + bounds.size.height - textRect.size.height; break ; case VerticalAlignmentMiddle: // Fall through. default : textRect.origin.y = bounds.origin.y + (bounds.size.height - textRect.size.height) / 2.0 ; } return textRect; } // 然后在drawTextInRect:方法中使用重新计算的CGRect -( void )drawTextInRect:(CGRect)requestedRect { CGRect actualRect = [self textRectForBounds:requestedRect limitedToNumberOfLines:self.numberOfLines]; [ super drawTextInRect:actualRect]; }

三、竖排显示文字时，如何让汉字竖排，而英文和数字为横排

汉字竖排显示没有压力，但是如果英文也都竖排显示就很难读懂了。
我这里的做法是：
1、拆分label的内容，把汉字、英文拆分开，并放在多个label中显示。
2、英文横排显示，然后把label旋转90度。

代码如下：
a) 拆分内容

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 /** * 拆分标题中的中文与非中文 */ - (NSArray *)splitTitle:(NSString *)title { NSArray *stringItemArray = [[NSMutableArray alloc] init]; int type = 0 ; if ([self isChinese:title index: 0 ]) { type = 1 ; } else { type = 0 ; } int fromIndex = 0 ; int toIndex = 0 ; for ( int i = 1 ; i < title.length; i++) { if (type == 1 ) { if ([self isChinese:title index:i]) { if (i == title.length - 1 ) { StringItem *item = [[StringItem alloc] init]; item.isChinese = [self isChinese:title index:i]; item.content = [title substringWithRange:NSMakeRange(fromIndex, title.length - fromIndex)]; [stringItemArray addObject:item]; [item release]; } toIndex = i; } else { type = 0 ; StringItem *item = [[StringItem alloc] init]; item.isChinese = YES; item.content = [title substringWithRange:NSMakeRange(fromIndex, toIndex - fromIndex + 1 )]; [stringItemArray addObject:item]; [item release]; fromIndex = i; toIndex = i; if (i == title.length - 1 ) { StringItem *item = [[StringItem alloc] init]; item.isChinese = [self isChinese:title index:i]; item.content = [title substringWithRange:NSMakeRange(fromIndex, title.length - fromIndex)]; [stringItemArray addObject:item]; [item release]; } } } else { if (![self isChinese:title index:i]) { if (i == title.length - 1 ) { StringItem *item = [[StringItem alloc] init]; item.isChinese = [self isChinese:title index:i]; item.content = [title substringWithRange:NSMakeRange(fromIndex, title.length - fromIndex)]; [stringItemArray addObject:item]; [item release]; } toIndex = i; } else { type = 1 ; StringItem *item = [[StringItem alloc] init]; item.isChinese = NO; item.content = [title substringWithRange:NSMakeRange(fromIndex, toIndex - fromIndex + 1 )]; [stringItemArray addObject:item]; [item release]; fromIndex = i; toIndex = i; if (i == title.length - 1 ) { StringItem *item = [[StringItem alloc] init]; item.isChinese = [self isChinese:title index:i]; item.content = [title substringWithRange:NSMakeRange(fromIndex, title.length - fromIndex)]; [stringItemArray addObject:item]; [item release]; } } } } return stringItemArray; } //判断是否是中文 - (BOOL)isChinese:(NSString *)str index:( int )index { NSRange range = NSMakeRange(index, 1 ); NSString *subString = [str substringWithRange:range]; const char *cString = [subString UTF8String]; if (strlen(cString) == 3 ) { return YES; } else { return NO; } }

b) 处理多个label，非中文的label旋转90度

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 CGRect frame = self.frame; UIFont *font = [UIFont systemFontOfSize: 16 ]; float height = 40 ; for (StringItem *item in stringItemArray) { if (item.isChinese) { CGSize size = [self getSize:item.content font:font]; VerticallyAlignedLabel *label = [[VerticallyAlignedLabel alloc] initWithFrame:CGRectMake((frame.size.width - size.width) / 2 , height, size.width, size.height)]; label.verticalAlignment = VerticalAlignmentTop; label.textAlignment = UITextAlignmentCenter; label.textColor = textColor; label.font = font; label.backgroundColor = [UIColor clearColor]; [label setLineBreakMode:UILineBreakModeWordWrap]; label.text = item.content; label.numberOfLines = 0 ; [self addSubview:label]; height = height + label.frame.size.height; } else { CGSize size = [self getVerSize:item.content font:font]; VerticallyAlignedLabel *label = [[VerticallyAlignedLabel alloc] initWithFrame:CGRectMake((frame.size.width - size.height) / 2 , height, size.height > frame.size.height - height ? frame.size.height - height : size.width, size.height)]; label.verticalAlignment = VerticalAlignmentTop; label.textAlignment = UITextAlignmentCenter; label.textColor = textColor; label.font = font; label.backgroundColor = [UIColor clearColor]; [label setLineBreakMode:UILineBreakModeWordWrap]; label.text = item.content; label.numberOfLines = 1 ; label.transform = CGAffineTransformMakeRotation(M_PI_2); label.frame = CGRectMake((frame.size.width - label.frame.size.width) / 2 , height, label.frame.size.width, label.frame.size.height); [self addSubview:label]; height = height + label.frame.size.height; } }