与NSString类似,在iOS中AttributedString也分为NSAttributedString和NSMutableAttributedString,不同的是,AttributedString对象多了一个Attribute的概念,一个AttributedString的对象包含很多的属性,每一个属性都有其对应的字符区域,在这里是使用NSRange来进行描述的。
使用AttributedString的方式通常有两种:
方式一:
首先初始化一个NSMutableAttributedString,然后向里面添加文字样式,最后将它赋给控件的AttributedText,该方法适合于文本较少而又需要分段精细控制的情况。
NSString *originStr = @"Hello,中秋节!";
//方式一
//创建 NSMutableAttributedString
NSMutableAttributedString *attributedStr01 = [[NSMutableAttributedString alloc] initWithString: originStr];
//添加属性
//给所有字符设置字体为Zapfino,字体高度为15像素
[attributedStr01 addAttribute: NSFontAttributeName value: [UIFont fontWithName: @"Zapfino" size: 15]
range: NSMakeRange(0, originStr.length)];
//分段控制,最开始4个字符颜色设置成蓝色
[attributedStr01 addAttribute: NSForegroundColorAttributeName value: [UIColor blueColor] range: NSMakeRange(0, 4)];
//分段控制,第5个字符开始的3个字符,即第5、6、7字符设置为红色
[attributedStr01 addAttribute: NSForegroundColorAttributeName value: [UIColor redColor] range: NSMakeRange(4, 3)];
//赋值给显示控件label01的 attributedText
_label01.attributedText = attributedStr01;
方式二:
首先创建属性字典,初始化各种属性,然后和需要控制的文本一起创建并赋值给控件的AttributedText,该方法适合于需要控制的文本较多整体控制的情况,通常是从文件中读取的大段文本控制。
//方式二
//创建属性字典
NSDictionary *attrDict = @{ NSFontAttributeName: [UIFont fontWithName: @"Zapfino" size: 15],
NSForegroundColorAttributeName: [UIColor blueColor] };
//创建 NSAttributedString 并赋值
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict];
通过对比两个例子可以看出,方式一比较容易处理复杂的格式,但是属性设置比较繁多复杂,而方式二的属性设置比较简单明了,却不善于处理复杂多样的格式控制,但是不善于并不等于不能,可以通过属性字符串分段的方式来达到方式一的效果,如下:
//方式二的分段处理
//第一段
NSDictionary *attrDict1 = @{ NSFontAttributeName: [UIFont fontWithName: @"Zapfino" size: 15],
NSForegroundColorAttributeName: [UIColor blueColor] };
NSAttributedString *attrStr1 = [[NSAttributedString alloc] initWithString: [originStr substringWithRange: NSMakeRange(0, 4)] attributes: attrDict1];
//第二段
NSDictionary *attrDict2 = @{ NSFontAttributeName: [UIFont fontWithName: @"Zapfino" size: 15],
NSForegroundColorAttributeName: [UIColor redColor] };
NSAttributedString *attrStr2 = [[NSAttributedString alloc] initWithString: [originStr substringWithRange: NSMakeRange(4, 3)] attributes: attrDict2];
//第三段
NSDictionary *attrDict3 = @{ NSFontAttributeName: [UIFont fontWithName: @"Zapfino" size: 15],
NSForegroundColorAttributeName: [UIColor blackColor] };
NSAttributedString *attrStr3 = [[NSAttributedString alloc] initWithString: [originStr substringWithRange:
NSMakeRange(7, originStr.length - 4 - 3)] attributes: attrDict3];
//合并
NSMutableAttributedString *attributedStr03 = [[NSMutableAttributedString alloc] initWithAttributedString: attrStr1];
[attributedStr03 appendAttributedString: attrStr2];
[attributedStr03 appendAttributedString: attrStr3];
_label03.attributedText = attributedStr03;
好了,讲完AttributedString的创建方式,下面研究下AttributedString究竟可以设置哪些属性,具体来说,有以下21个:
// NSFontAttributeName 设置字体属性,默认值:字体:Helvetica(Neue) 字号:12
// NSForegroundColorAttributeNam 设置字体颜色,取值为 UIColor对象,默认值为黑色
// NSBackgroundColorAttributeName 设置字体所在区域背景颜色,取值为 UIColor对象,默认值为nil, 透明色
// NSLigatureAttributeName 设置连体属性,取值为NSNumber 对象(整数),0 表示没有连体字符,1 表示使用默认的连体字符
// NSKernAttributeName 设定字符间距,取值为 NSNumber 对象(整数),正值间距加宽,负值间距变窄
// NSStrikethroughStyleAttributeName 设置删除线,取值为 NSNumber 对象(整数)
// NSStrikethroughColorAttributeName 设置删除线颜色,取值为 UIColor 对象,默认值为黑色
// NSUnderlineStyleAttributeName 设置下划线,取值为 NSNumber 对象(整数),枚举常量 NSUnderlineStyle中的值,与删除线类似
// NSUnderlineColorAttributeName 设置下划线颜色,取值为 UIColor 对象,默认值为黑色
// NSStrokeWidthAttributeName 设置笔画宽度,取值为 NSNumber 对象(整数),负值填充效果,正值中空效果
// NSStrokeColorAttributeName 填充部分颜色,不是字体颜色,取值为 UIColor 对象
// NSShadowAttributeName 设置阴影属性,取值为 NSShadow 对象
// NSTextEffectAttributeName 设置文本特殊效果,取值为 NSString 对象,目前只有图版印刷效果可用:
// NSBaselineOffsetAttributeName 设置基线偏移值,取值为 NSNumber (float),正值上偏,负值下偏
// NSObliquenessAttributeName 设置字形倾斜度,取值为 NSNumber (float),正值右倾,负值左倾
// NSExpansionAttributeName 设置文本横向拉伸属性,取值为 NSNumber (float),正值横向拉伸文本,负值横向压缩文本
// NSWritingDirectionAttributeName 设置文字书写方向,从左向右书写或者从右向左书写
// NSVerticalGlyphFormAttributeName 设置文字排版方向,取值为 NSNumber 对象(整数),0 表示横排文本,1 表示竖排文本
// NSLinkAttributeName 设置链接属性,点击后调用浏览器打开指定URL地址
// NSAttachmentAttributeName 设置文本附件,取值为NSTextAttachment对象,常用于文字图片混排
// NSParagraphStyleAttributeName 设置文本段落排版格式,取值为 NSParagraphStyle 对象
下面就一一举例说明:
1. NSFontAttributeName
//NSForegroundColorAttributeName 设置字体颜色,取值为 UIColor,默认为黑色
NSDictionary *attrDict1 = @{ NSForegroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict2 = @{ NSForegroundColorAttributeName: [UIColor blueColor] };
NSDictionary *attrDict3 = @{ NSForegroundColorAttributeName: [UIColor orangeColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
注意:
NSForegroundColorAttributeName设置的颜色与UILabel的textColor属性设置的颜色在地位上是相等的,谁最后赋值,最终显示的就是谁的颜色。
2. NSBackgroundColorAttributeName
//NSForegroundColorAttributeName 设置字体颜色,取值为 UIColor,默认为黑色
NSDictionary *attrDict1 = @{ NSForegroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict2 = @{ NSForegroundColorAttributeName: [UIColor blueColor] };
NSDictionary *attrDict3 = @{ NSForegroundColorAttributeName: [UIColor orangeColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
//NSBackgroundColorAttributeName 设置字体所在区域背景的颜色,取值为UIColor,默认值为nil
NSDictionary *attrDict4 = @{ NSBackgroundColorAttributeName: [UIColor orangeColor] };
NSDictionary *attrDict5 = @{ NSBackgroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict6 = @{ NSBackgroundColorAttributeName: [UIColor cyanColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict4];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict5];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict6];
仔细观察会发现个问题,我并没有关闭 NSForegroundColorAttributeName 属性,但是在运行结果中,所有字体的颜色都变成了默认色——黑色,这说明 NSForegroundColorAttributeName 和 NSBackgroundColorAttributeName 的地位是相等的,跟前面介绍的 textColor 一样,哪个属性最后一次赋值,就会冲掉前面的效果,若是我们把属性代码顺序交换一下
//NSBackgroundColorAttributeName 设置字体所在区域背景的颜色,取值为UIColor,默认值为nil
NSDictionary *attrDict4 = @{ NSBackgroundColorAttributeName: [UIColor orangeColor] };
NSDictionary *attrDict5 = @{ NSBackgroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict6 = @{ NSBackgroundColorAttributeName: [UIColor cyanColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict4];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict5];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict6];
//NSForegroundColorAttributeName 设置字体颜色,取值为 UIColor,默认为黑色
NSDictionary *attrDict1 = @{ NSForegroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict2 = @{ NSForegroundColorAttributeName: [UIColor blueColor] };
NSDictionary *attrDict3 = @{ NSForegroundColorAttributeName: [UIColor orangeColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
但是textColor属性可以与 NSBackgroundColorAttributeName 属性叠加
_label01.textColor = [UIColor greenColor];
_label02.textColor = [UIColor yellowColor];
_label03.textColor = [UIColor blueColor];
//NSForegroundColorAttributeName 设置字体颜色,取值为 UIColor,默认为黑色
NSDictionary *attrDict1 = @{ NSForegroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict2 = @{ NSForegroundColorAttributeName: [UIColor blueColor] };
NSDictionary *attrDict3 = @{ NSForegroundColorAttributeName: [UIColor orangeColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
//NSBackgroundColorAttributeName 设置字体所在区域背景的颜色,取值为UIColor,默认值为nil
NSDictionary *attrDict4 = @{ NSBackgroundColorAttributeName: [UIColor orangeColor] };
NSDictionary *attrDict5 = @{ NSBackgroundColorAttributeName: [UIColor redColor] };
NSDictionary *attrDict6 = @{ NSBackgroundColorAttributeName: [UIColor cyanColor] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict4];
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict5];
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict6];
虽然 textColor 在 NSFontAttributeName 之前赋值,但是由于 NSFontAttributeName 的属性效果被NSBackgroundColorAttributeName 属性冲掉了,所以最终显示了 textColor 的颜色。
3. NSLigatureAttributeName
//NSLigatureAttributeName 设置连体属性,取值为NSNumber 对象(整数),0 表示没有连体字符,1 表示使用默认的连体字符,
// 2 表示使用所有连体符号,默认值为 1(iOS 不支持 2)
NSString *ligatureStr = @"flush";
NSDictionary *attrDict1 = @{ NSLigatureAttributeName: [NSNumber numberWithInt: 0],
NSFontAttributeName: [UIFont fontWithName: @"futura" size: 30] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: ligatureStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSLigatureAttributeName: @(1),
NSFontAttributeName: [UIFont fontWithName: @"futura" size: 30]
};
_label02.attributedText = [[NSAttributedString alloc] initWithString: ligatureStr attributes: attrDict2];
由于要展示连体字符,所以将前面使用的带有中文的字符串换成 flush
NSLigatureAttributeName的取值为NSNumber对象,所以不能直接将一个整数值赋给它,创建 NSNumber 对象的方法有很多,或者可以简写成 @(int)
注意观察字母f和l之间的变化。
感觉连写就是一个艺术字功能,当字符f和l组合使用组合符号(所谓的字形(glyph))绘制时,看起来确实更加美观。但是并非所有的字符之间都有组合符号,事实上,只有某些字体中得某些字符的组合(如字符f和l,字符f和i等)才具有美观的组合符号。
4. NSKernAttributeName
//NSKernAttributeName 设定字符间距,取值为 NSNumber 对象(整数),正值间距加宽,负值间距变窄
NSDictionary *attrDict1 = @{ NSKernAttributeName: @(-3),
NSFontAttributeName: [UIFont systemFontOfSize: 20]
};
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSKernAttributeName: @(0),
NSFontAttributeName: [UIFont systemFontOfSize: 20]
};
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSKernAttributeName: @(10),
NSFontAttributeName: [UIFont systemFontOfSize: 20]
};
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
5. NSStrikethroughStyleAttributeName
//NSStrikethroughStyleAttributeName 设置删除线,取值为 NSNumber 对象(整数),枚举常量 NSUnderlineStyle中的值
// NSUnderlineStyleNone 不设置删除线
// NSUnderlineStyleSingle 设置删除线为细单实线
// NSUnderlineStyleThick 设置删除线为粗单实线
// NSUnderlineStyleDouble 设置删除线为细双实线
NSDictionary *attrDict1 = @{ NSStrikethroughStyleAttributeName: @(NSUnderlineStyleSingle),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSStrikethroughStyleAttributeName: @(NSUnderlineStyleThick),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSStrikethroughStyleAttributeName: @(NSUnderlineStyleDouble),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
注意:
虽然使用了枚举常量,但是枚举常量的本质仍为整数,所以同样必须先转化为 NSNumber 才能使用
删除线和下划线使用相同的枚举常量作为其属性值
目前iOS中只有上面列出的4中效果,虽然我们能够在头文件中发现其他更多的取值,但是使用后没有任何效果
可以看出,中文和英文删除线的位置有所不同
另外,删除线属性取值除了上面的4种外,其实还可以取其他整数值,有兴趣的可以自行试验,取值为 0 - 7时,效果为单实线,随着值得增加,单实线逐渐变粗,取值为 9 - 15时,效果为双实线,取值越大,双实线越粗。
NSDictionary *attrDict1 = @{ NSStrikethroughStyleAttributeName: @(1),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSStrikethroughStyleAttributeName: @(3),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSStrikethroughStyleAttributeName: @(7),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
6. NSStrikethroughColorAttributeName
//NSStrikethroughColorAttributeName 设置删除线颜色,取值为 UIColor 对象,默认值为黑色
NSDictionary *attrDict1 = @{ NSStrikethroughColorAttributeName: [UIColor blueColor],
NSStrikethroughStyleAttributeName: @(1),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSStrikethroughColorAttributeName: [UIColor orangeColor],
NSStrikethroughStyleAttributeName: @(3),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSStrikethroughColorAttributeName: [UIColor greenColor],
NSStrikethroughStyleAttributeName: @(7),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
7. NSUnderlineStyleAttributeName
下划线除了线条位置和删除线不同外,其他的都可以完全参照删除线设置。
//NSUnderlineStyleAttributeName 设置下划线,取值为 NSNumber 对象(整数),枚举常量 NSUnderlineStyle中的值,与删除线类似
NSDictionary *attrDict1 = @{ NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSUnderlineStyleAttributeName: @(NSUnderlineStyleThick),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSUnderlineStyleAttributeName: @(NSUnderlineStyleDouble),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
8. NSUnderlineColorAttributeName
可以完全参照下划线颜色设置
//NSUnderlineColorAttributeName 设置下划线颜色,取值为 UIColor 对象,默认值为黑色
NSDictionary *attrDict1 = @{ NSUnderlineColorAttributeName: [UIColor blueColor],
NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSUnderlineColorAttributeName: [UIColor orangeColor],
NSUnderlineStyleAttributeName: @(NSUnderlineStyleThick),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSUnderlineColorAttributeName: [UIColor greenColor],
NSUnderlineStyleAttributeName: @(NSUnderlineStyleDouble),
NSFontAttributeName: [UIFont systemFontOfSize:20] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
9. NSStrokeWidthAttributeName
//NSStrokeWidthAttributeName 设置笔画宽度,取值为 NSNumber 对象(整数),负值填充效果,正值中空效果
NSDictionary *attrDict1 = @{ NSStrokeWidthAttributeName: @(-3),
NSFontAttributeName: [UIFont systemFontOfSize:30] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSStrokeWidthAttributeName: @(0),
NSFontAttributeName: [UIFont systemFontOfSize:30] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSStrokeWidthAttributeName: @(3),
NSFontAttributeName: [UIFont systemFontOfSize:30] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];
10. NSStrokeColorAttributeName
//NSStrokeColorAttributeName 填充部分颜色,不是字体颜色,取值为 UIColor 对象
NSDictionary *attrDict1 = @{ NSStrokeWidthAttributeName: @(-3),
NSStrokeColorAttributeName: [UIColor orangeColor],
NSFontAttributeName: [UIFont systemFontOfSize:30] };
_label01.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict1];
NSDictionary *attrDict2 = @{ NSStrokeWidthAttributeName: @(0),
NSStrokeColorAttributeName: [UIColor blueColor],
NSFontAttributeName: [UIFont systemFontOfSize:30] };
_label02.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict2];
NSDictionary *attrDict3 = @{ NSStrokeWidthAttributeName: @(3),
NSStrokeColorAttributeName: [UIColor greenColor],
NSFontAttributeName: [UIFont systemFontOfSize:30] };
_label03.attributedText = [[NSAttributedString alloc] initWithString: originStr attributes: attrDict3];