常用属性
| key | value | 说明 |
|---|---|---|
| NSFontAttributeName | UIFont对象 | 字体大小：默认Helvetica(Neue) 12 |
| NSParagraphStyleAttributeName | NSParagraphStyle对象 | 段落设置 |
| NSForegroundColorAttributeName | UIColor对象 | 字体颜色，默认blackColor |
| NSBackgroundColorAttributeName | UIColor对象 | 背景色，默认nil(无背景色) |
| NSLigatureAttributeName | 包含整数的NSNumber对象 | 连字符：默认为1:默认连接，0:不连接 |
| NSKernAttributeName | 包含浮点数的NSNumber对象 | 字符间距：默认0（禁用） |
| NSTrackingAttributeName | 包含浮点数的NSNumber对象 | 修改默认跟踪的数量。0表示禁用跟踪。iOS14及以后系统可用。 |
| NSStrikethroughStyleAttributeName | 包含整数的NSNumber对象 | 删除线：默认0（无删除线） |
| NSUnderlineStyleAttributeName | 包含整数的NSNumber对象 | 下划线：默认0（无下划线） |
| NSStrokeColorAttributeName | UIColor对象 | 描边颜色：nil（和文字的 foregroundColor一致） |
| NSStrokeWidthAttributeName | 包含浮点数的NSNumber对象 | 描边宽度：正值空心描边，负值实心描边，默认0(不描边) |
| NSShadowAttributeName | NSShadow对象 | 文本阴影,默认为nil:无阴影 |
| NSTextEffectAttributeName | NSString对象 | 文字效果：默认nil(没有文字效果) |
| NSAttachmentAttributeName | NSTextAttachment对象 | 附件(常用作图文混排) ：默认nil(没有附件) |
| NSLinkAttributeName | NSURL (优先) 或 NSString对象 | 链接 |
| NSBaselineOffsetAttributeName | 包含浮点数的NSNumber对象 | 基线偏移量，默认为0;正值向上偏移，负值向下偏移，默认0（不偏移） |
| NSUnderlineColorAttributeName | UIColor对象 | 下划线颜色：默认nil（和文字的 foregroundColor一致） |
| NSStrikethroughColorAttributeName | UIColor对象 | 删除线颜色：默认 nil（和文字的 foregroundColor一致） |
| NSObliquenessAttributeName | 包含浮点数的NSNumber对象 | 字体倾斜 ：正值向右倾斜，负值向左倾斜， 默认0（不倾斜） |
| NSExpansionAttributeName | 包含浮点数的NSNumber对象 | 文本扁平化：正值横向拉伸，负值横向压缩，默认0（不拉伸） |
| NSWritingDirectionAttributeName | 存储NSNumber类型的NSArray对象 | 书写方向。控制字符可以通过屏蔽NSWritingDirection和NSWritingDirectionFormatType值来获得。 LRE: NSWritingDirectionLeftToRight\NSWritingDirectionEmbedding, RLE: NSWritingDirectionRightToLeft\NSWritingDirectionEmbedding, LRO: NSWritingDirectionLeftToRight\NSWritingDirectionOverride, RLO: NSWritingDirectionRightToLeft\NSWritingDirectionOverride |
| NSVerticalGlyphFormAttributeName | 包含整数的NSNumber对象 | 0表示水平文本。1表示垂直文本。如果没有指定，它可以遵循更高级别的垂直方向设置。目前在iOS上，它总是水平的。任何其他值的行为是未定义的。 |
示例
NSLigatureAttributeName-连字符
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"逗号前面的我是一个没有连字符样式的fl，逗号后面的你是一个带连字符样式的fl（你看后半句的汉字连字符样式好难体现出来哦)";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
// 设置文本前半句无连字符效果
[att addAttribute:NSLigatureAttributeName value:[NSNumber numberWithInt:0] range:NSMakeRange(0, 19)];
// 设置文本后半句有连字符效果
[att addAttribute:NSLigatureAttributeName value:[NSNumber numberWithInt:1] range:NSMakeRange(19, text.length - 19)];
att.png
NSKernAttributeName - 字符间距
注意： 正值间距加宽，负值间距变窄，0表示默认效果
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"设置我的字间距为正值20有拉大效果，中间的你是正常效果，设置他的字间距为负值-5有减少效果";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSKernAttributeName value:@20 range:NSMakeRange(0, 18)];
[att addAttribute:NSKernAttributeName value:@(-5) range:NSMakeRange(28, text.length - 28)];
att.png
文字描边
NSStrokeColorAttributeName - 描边颜色
NSStrokeWidthAttributeName - 描边宽度
- 描边颜色要搭配非0的描边宽度才会生效，如果只设置了描边颜色，描边宽度为0，则没有描边效果
- 描边宽度是正数，会对文字进行描边，但文字中心不填充（ 一种经典的空心文本样式是在该值为3.0）
- 描边宽度是负数，会对文字进行描边，而且会同时对文字中心进行填充（填充的颜色为文字本来的字体颜色）
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"只设置描边颜色，没有设置描边宽度（默认为0），没有效果";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSStrokeColorAttributeName value:[UIColor blueColor] range:NSMakeRange(0, text.length)];
att.png
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"将描边宽度设置为正数3，无描边颜色，具有空心效果哦，此时描边颜色默认成字体本来的颜色！";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSStrokeWidthAttributeName value:@(3) range:NSMakeRange(0, text.length)];
att.png
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"将描边宽度设置为正数3，描边颜色为红色，具有空心效果哦，因为正数不对文字内部进行填充！";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSStrokeColorAttributeName value:[UIColor redColor] range:NSMakeRange(0, text.length)];
[att addAttribute:NSStrokeWidthAttributeName value:@(3) range:NSMakeRange(0, text.length)];
att.png
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"将描边宽度设置为负数-3，又设置描边颜色，无空心效果，因为负数会对文字内部进行填充！";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSStrokeColorAttributeName value:[UIColor purpleColor] range:NSMakeRange(0, text.length)];
[att addAttribute:NSStrokeWidthAttributeName value:@(-3) range:NSMakeRange(0, text.length)];
att.png
NSShadowAttributeName-阴影
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"一个有阴影的文本！";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
// 创建NSShadow实例
NSShadow *shadow = [[NSShadow alloc] init];
shadow.shadowColor = [UIColor purpleColor];
shadow.shadowBlurRadius = 3.0;
shadow.shadowOffset = CGSizeMake(0, 0.8);
// 添加属性
[att addAttribute:NSShadowAttributeName value:shadow range:NSMakeRange(0, text.length)];
att.png
NSTextEffectAttributeName-文字效果
UIFont *font = [UIFont fontWithName:@"futura" size:18];
NSString *text = @"我是没有文字效果的，你是有文字效果的！";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
// [attributes setObject:[UIColor darkGrayColor] forKey:NSBackgroundColorAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSTextEffectAttributeName value:NSTextEffectLetterpressStyle range:NSMakeRange(10, text.length - 10)];
att.png
att.png
NSLinkAttributeName - 链接
注意：UILabel无法使用该属性, 但UITextView 控件可以使用，所以下面关于 NSLinkAttributeName 属性的代码也是使用 UITextView 来测试的。
// 注意：跳转链接要实现UITextView的这个委托方法
- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)url inRange:(NSRange)characterRange {
return YES;
}
- (void)linkAttributeTest {
NSString *text = @"点我跳转到百度哦！";
NSMutableAttributedString * attributeStr = [[NSMutableAttributedString alloc] initWithString:text];
NSURL *url = [NSURL URLWithString:@"https://www.baidu.com"];
[attributeStr addAttribute:NSLinkAttributeName value:url range:NSMakeRange(0, text.length)];
self.textView.attributedText = attributeStr;
}
NSBaselineOffsetAttributeName-基准线
注意：正值向上偏移，负值向下偏移，默认0（不偏移）
UIFont *font = [UIFont fontWithName:@"Savoye Let" size:18];
NSString *text = @"负值向下偏移";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSBaselineOffsetAttributeName value:@(-10) range:NSMakeRange(0, text.length)];
att.png
att.png
att.png
NSExpansionAttributeName -文本扁平化（横向拉伸）
注意：正值横向拉伸，负值横向压缩，默认0（不拉伸）
UIFont *font = [UIFont fontWithName:@"Savoye Let" size:18];
NSString *text = @"正值横向拉伸，无扁平效果，负值横向压缩！";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSExpansionAttributeName value:@(0.8) range:NSMakeRange(0, 7)];
[att addAttribute:NSExpansionAttributeName value:@(-0.8) range:NSMakeRange(13, text.length - 13)];
att.png
NSTrackingAttributeName
类似NSKernAttributeName。
UIFont *font = [UIFont fontWithName:@"Savoye Let" size:18];
NSString *text = @"NSTrackingAttributeName，NSTrackingAttributeName，NSTrackingAttributeName";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSTrackingAttributeName value:@(8.8) range:NSMakeRange(0, 23)];
[att addAttribute:NSTrackingAttributeName value:@(-8.8) range:NSMakeRange(46, 23)];
att.png
段落设置
NSMutableParagraphStyle
| 属性 | 说明 |
|---|---|
| lineSpacing | 行间距 |
| paragraphSpacing | 段落间距 |
| alignment | 对齐方式 |
| firstLineHeadIndent | 首行缩进 |
| headIndent | 整段缩进 |
| tailIndent | 右侧缩进 |
| lineBreakMode | 截断方式 |
| minimumLineHeight | 最小行高 |
| maximumLineHeight | 最大行高 |
| baseWritingDirection | 书写方向 |
| lineHeightMultiple | 行间距倍数 |
| paragraphSpacingBefore | 段首行空白空间 |
| hyphenationFactor | 连字属性 在iOS，唯一支持的值分别为0和1 |
| tabStops | 制表符 |
| allowsDefaultTighteningForTruncation | 收缩字符间距允许截断 |
UIFont *font = [UIFont fontWithName:@"Savoye Let" size:18];
NSString *text = @"段落\n右对齐\n行间距20";
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc]init];
style.lineBreakMode = NSLineBreakByWordWrapping;
style.alignment = NSTextAlignmentRight;
style.lineSpacing = 20;
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:style forKey:NSParagraphStyleAttributeName];
[attributes setObject:font forKey:NSFontAttributeName];
NSAttributedString *att = [[NSAttributedString alloc] initWithString:text attributes:attributes];
att.png
不同大小的字体对齐
默认基线对齐。iOS UIFont简介与文本行数判断
居中原理.jpg
UIFont *font = [UIFont systemFontOfSize:21];
UIFont *font2 = [UIFont systemFontOfSize:14];
NSString *text = @"1😄不同大小的字体底部对齐😄样式（默认）\n2😄不同大小的字体顶部对齐😄样式\n3😄不同大小的字体中间对齐😄样式";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
[att addAttribute:NSFontAttributeName value:font2 range:NSMakeRange(10, 6)];
[att addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(10, 6)];
[att addAttribute:NSFontAttributeName value:font2 range:NSMakeRange(33, 6)];
[att addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(33, 6)];
[att addAttribute:NSBaselineOffsetAttributeName value:@(font.ascender - font2.ascender) range:NSMakeRange(33, 6)];
[att addAttribute:NSFontAttributeName value:font2 range:NSMakeRange(52, 6)];
[att addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(52, 6)];
[att addAttribute:NSBaselineOffsetAttributeName value:@((font.lineHeight - font2.lineHeight)/2 + ((font.descender - font2.descender))) range:NSMakeRange(52, 6)];
att.png
图片
图片
UIFont *font = [UIFont systemFontOfSize:24];
NSString *text = @"富文本图片";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
[attributes setObject:[UIColor yellowColor] forKey:NSBackgroundColorAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
NSLog(@"纯文字:%ld",att.length);
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
attachment.image = [UIImage imageNamed:@"1"];
attachment.bounds = CGRectMake(0,0,30,20);
[att appendAttributedString:[NSAttributedString attributedStringWithAttachment:attachment]];
NSLog(@"文字+图片:%ld",att.length);
att.png
图片长度
UIFont *font = [UIFont systemFontOfSize:24];
NSString *text = @"富文本图片";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
[attributes setObject:[UIColor yellowColor] forKey:NSBackgroundColorAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
NSLog(@"纯文字:%ld",att.length);
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
attachment.image = nil;
attachment.bounds = CGRectMake(0,0,30,20);
[att appendAttributedString:[NSAttributedString attributedStringWithAttachment:attachment]];
NSLog(@"文字+图片:%ld",att.length);
att.png
纯文字:5
文字+图片:6
图片添加至NSTextAttachment生成富文本后，占一个字节长度（无论图片大小或是否存在）。
图片对齐
NSTextAttachment默认也是基线对齐，attachment.bounds的坐标原点Y轴是和基线持平，是CoreGraphics的坐标系。
原理同上述文字对齐。
UIFont *font = [UIFont systemFontOfSize:24];
NSString *text = @"富文本图片";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
[attributes setObject:[UIColor yellowColor] forKey:NSBackgroundColorAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
NSLog(@"纯文字:%ld",att.length);
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
attachment.image = [UIImage imageNamed:@"1"];
attachment.bounds = CGRectMake(0,0,30,20);
[att appendAttributedString:[NSAttributedString attributedStringWithAttachment:attachment]];
[att addAttribute:NSBaselineOffsetAttributeName value:@((font.lineHeight - 20)/2 + (font.descender)) range:NSMakeRange(5, 1)];
NSLog(@"文字+图片:%ld",att.length);
att.png
UIFont *font = [UIFont systemFontOfSize:24];
NSString *text = @"文本\n富文本图片\n文本";
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:font forKey:NSFontAttributeName];
[attributes setObject:[UIColor yellowColor] forKey:NSBackgroundColorAttributeName];
NSMutableAttributedString *att = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
NSLog(@"纯文字:%ld",att.length);
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
attachment.image = [UIImage imageNamed:@"1"];
attachment.bounds = CGRectMake(0,0,30,20);
NSAttributedString *textAtt = [NSAttributedString attributedStringWithAttachment:attachment];
[att insertAttributedString:textAtt atIndex:6];
[att addAttribute:NSBaselineOffsetAttributeName value:@((font.lineHeight - 20)/2 + (font.descender)) range:NSMakeRange(6, 1)];
NSLog(@"文字+图片:%ld",att.length);
att.png
文字图片间隔
NSKernAttributeName属性对图片与文字的间距设置不生效。
网络图片
判断网络图片是否存在，不存在先试用占位图，开启异步下载，下载完成后重新生成富文本替换。
参考文档
iOS富文本NSAttributedString垂直对齐
iOS--NSAttributedString超全属性详解及应用（富文本、图文混排）
