iOS富文本： NSMutableAttributedString + 链式编程 = 超简单的富文本编辑

CCAttributedString

CCAttributedString是我整理NSMutableAttributedString中AttributedName属性封装好的一个分类，通过链式编程，可以轻松完成对富文本的编辑。不多说，看效果吧。

代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    
    NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"通过NSRange添加效果\n给第三个123123123加特效\n给所有的123123123加特效\n拉开距离\n扁平\n脉动不回来了\n一条线两条线删除线\n空心 实心\nfl是连在一起的\n听说代写多了，眼睛会花\n凸版印刷效果\n正常状态和设置偏移量后\n让我打一套组合拳\n这句话是反的\n最后我选择滑稽"];
    
    string.textColor([UIColor redColor]).font([UIFont systemFontOfSize:30]).range(NSMakeRange(2, 7));
    
    string.textColor([UIColor redColor]).font([UIFont systemFontOfSize:10]).backgroundColor([UIColor darkGrayColor]).rangeIndex(2).rangeString(@[@"3",@"1"]);
    string.textColor([UIColor blackColor]).font([UIFont boldSystemFontOfSize:30]).all().rangeString(@"2");
    string.textSpace(10).rangeString(@"拉开距离");
    string.textColor([UIColor blackColor]).font([UIFont systemFontOfSize:30]).backgroundColor([UIColor cyanColor]).rangeString(@"本质");
    string.obliqueness(YES).textColor([UIColor orangeColor]).rangeString(@"脉动不回来了");
    string.expansion(YES).textColor([UIColor purpleColor]).rangeString(@"扁平");
    string.underline(YES).underlineColor([UIColor orangeColor]).rangeString(@"一条线");
    string.underline(NSUnderlineStyleDouble).underlineColor([UIColor blueColor]).rangeString(@"两条线");
    string.strikethrough(YES).strikethroughColor([UIColor redColor]).rangeString(@"删除线");
    string.strokeWidth(5).strokeColor([UIColor brownColor]).font([UIFont systemFontOfSize:30]).rangeString(@"空心");
    string.strokeWidth(-5).strokeColor([UIColor brownColor]).font([UIFont systemFontOfSize:30]).rangeString(@"实心");
    string.ligature(YES).font([UIFont fontWithName: @"futura" size: 30]).textColor([UIColor redColor]).rangeIndex(0).rangeString(@"fl");
    string.effectLetterpressStyle(YES).rangeString(@"凸版印刷效果");
    string.textColor([UIColor darkGrayColor]).font([UIFont systemFontOfSize:8]).baselineOffset(10).rangeString(@"设置偏移量后");
    string.textColor([UIColor grayColor]).backgroundColor([UIColor orangeColor]).textSpace(10).obliqueness(YES).expansion(YES).underline(YES).underlineColor([UIColor blueColor]).strikethrough(YES).rangeString(@"让我打一套组合拳");
    string.writingDirection(@[@(NSWritingDirectionRightToLeft | NSTextWritingDirectionOverride)]).rangeString(@"这句话是反的");
    
    NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
    attachment.image = [UIImage imageNamed:@"huaji"];
    attachment.bounds = CGRectMake(0, -4, 20, 20);
    string.attachment(attachment,string.length);
    
    NSShadow *shadow = [[NSShadow alloc] init];
    shadow.shadowColor = [UIColor darkGrayColor];
    shadow.shadowOffset = CGSizeMake(2, 2);
    string.shadow(shadow).rangeString(@"听说代写多了，眼睛会花");
    
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height*4/5)];
    label.textColor = [UIColor blueColor];
    label.numberOfLines = 0;
    [self.view addSubview:label];
    label.attributedText = string;
    
    
    UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height*4/5, self.view.frame.size.width, self.view.frame.size.height/5)];
    textView.delegate = self;
    textView.editable = NO;
    [self.view addSubview:textView];
    NSMutableAttributedString *linkString = [[NSMutableAttributedString alloc] initWithString:@"textview\n这是一条链接"];
    linkString.link([NSURL URLWithString:@"https://www.baidu.com"]).textColor([UIColor orangeColor]).font([UIFont systemFontOfSize:20]).underline(YES).rangeString(@"链接");
    textView.attributedText = linkString;

}

效果：

熟悉Masonry的人都对链式写法司空见惯了，相比NSMutableAttributedString提供的方法，比如：

NSDictionary *attributeDict = [NSDictionary dictionaryWithObjectsAndKeys:
                                    [UIFontsystemFontOfSize:15.0],NSFontAttributeName,
                                    [UIColorredColor],NSForegroundColorAttributeName,
                                   NSUnderlineStyleAttributeName,NSUnderlineStyleSingle,nil];
NSMutableAttributedString *AttributedStr = [[NSMutableAttributedStringalloc]initWithString:@"富文本" attributes:attributeDict];

使用CCAttributedString可以一行之内解决战斗，最重要的是不用每次去翻文档找那一串参数名了：

string.font([UIFont systemFontOfSize:15]).textColor([UIColor redColor]).underline(YES).rangeString(@"xxxxx");

每次添加属性的时候，都需要以range()或rangeString()结束，所有的方法说明如下：

@interface NSMutableAttributedString (CCAttributedString)

- (NSMutableAttributedString *(^)(UIColor *))textColor;//字体颜色
- (NSMutableAttributedString *(^)(UIColor *))backgroundColor;//背景颜色
- (NSMutableAttributedString *(^)(UIFont *))font;//字号
- (NSMutableAttributedString *(^)(NSUnderlineStyle))underline;//下划线
- (NSMutableAttributedString *(^)(UIColor *))underlineColor;//下划线颜色
- (NSMutableAttributedString *(^)(UIColor *))strokeColor;//描边
- (NSMutableAttributedString *(^)(CGFloat))strokeWidth;//描边宽度
- (NSMutableAttributedString *(^)(BOOL))obliqueness;//斜体
- (NSMutableAttributedString *(^)(BOOL))expansion;//扁平体
- (NSMutableAttributedString *(^)(BOOL))strikethrough;//删除线
- (NSMutableAttributedString *(^)(UIColor *))strikethroughColor;//删除线颜色
- (NSMutableAttributedString *(^)(BOOL))ligature;//连体
- (NSMutableAttributedString *(^)(NSShadow *))shadow;//字体阴影
- (NSMutableAttributedString *(^)(BOOL))effectLetterpressStyle;//凸版印刷体
- (NSMutableAttributedString *(^)(CGFloat))baselineOffset;//字体偏移
- (NSMutableAttributedString *(^)(NSURL *))link;//URL链接
- (NSMutableAttributedString *(^)(id))writingDirection;//书写方向
- (NSMutableAttributedString *(^)(CGFloat))lineSpace;//行间距
- (NSMutableAttributedString *(^)(CGFloat))textSpace;//字间距
- (NSMutableAttributedString *(^)(NSTextAttachment *,NSInteger))attachment;//插入图片
- (NSMutableAttributedString *(^)(id))rangeString;//根据一串或一组字符串添加效果
- (NSMutableAttributedString *(^)(NSRange))range;//根据range添加效果
- (NSMutableAttributedString *(^)())all;//匹配所有的rangeString,添加效果
- (NSMutableAttributedString *(^)(NSInteger))rangeIndex;//给第几个rangeString添加效果

@end

一些注意到地方有，rangeString()这个方法可以传一个或一组字符串，all()可以找到所有目标字符串，rangeIndex()可以找到第n个目标字符串，以后我还会丰富它的功能。

实现原理

链式编程

通过返回一个返回值为NSMutableAttributedString的block，可以实现这种效果

- (NSMutableAttributedString *(^)(UIColor *))textColor {
    return ^ id (UIColor *color) {
        self.attributedBuilder.currentTextColor = color;
        return self;
    };
}

我建了一个名为CCAttributedStringBuilder的类，用来保存每个方法传过来的值，并在rangeString或range调用后给NSMutableAttributedString添加属性，最后清除掉当前builder保存的属性。

@interface CCAttributedStringBuilder : NSObject

@property (nonatomic, strong) UIColor *currentTextColor;
@property (nonatomic, strong) UIColor *currentBackgroundColor;
@property (nonatomic, strong) UIFont *currentFont;
@property (nonatomic, strong) NSNumber *obliqueness;
@property (nonatomic, strong) NSNumber *Expansion;
@property (nonatomic, strong) NSNumber *textSpace;
@property (nonatomic, strong) NSNumber *underline;
@property (nonatomic, strong) UIColor *underLineColor;
@property (nonatomic, strong) UIColor *strokeColor;
@property (nonatomic, strong) NSNumber *strokeWidth;
@property (nonatomic, strong) NSNumber *strikethrough;
@property (nonatomic, strong) UIColor *strikethroughColor;
@property (nonatomic, strong) NSNumber *ligature;
@property (nonatomic, strong) NSShadow *shadow;
@property (nonatomic, strong) NSNumber *effectLetterpressStyle;
@property (nonatomic, strong) NSNumber *baselineOffset;
@property (nonatomic, strong) NSURL *link;
/**
 @[@(NSWritingDirectionLeftToRight | NSTextWritingDirectionEmbedding)]
 @[@(NSWritingDirectionLeftToRight | NSTextWritingDirectionOverride)]
 @[@(NSWritingDirectionRightToLeft | NSTextWritingDirectionEmbedding)]
 @[@(NSWritingDirectionRightToLeft | NSTextWritingDirectionOverride)]
 */
@property (nonatomic, strong) id writingDirection;
@property (nonatomic, strong) NSNumber *all;
@property (nonatomic, strong) NSNumber *rangeIndex;
@property (nonatomic, assign) BOOL isAddingInArray;

@end

- (NSMutableAttributedString *(^)(id))rangeString {
    return ^ id (id rangeObj) {
        
        void(^addBlock)(NSString *) = ^ (NSString *targetString) {
            if (self.attributedBuilder.rangeIndex) {
                [self addAttributesAtRangeIndexWithObj:targetString];
            } else if (self.attributedBuilder.all && [self.attributedBuilder.all boolValue]) {
                [self addAttributesAllWithObj:targetString];
            } else {
                [self addAttributesWithObj:targetString];
            }
        };
        
        if ([rangeObj isKindOfClass:[NSString class]]) {
            addBlock(rangeObj);
        } else if ([rangeObj isKindOfClass:[NSArray class]]) {
            for (id obj in rangeObj) {
                if ([obj isKindOfClass:[NSString class]]) {
                    self.attributedBuilder.isAddingInArray = !([obj isEqual:[rangeObj lastObject]]);
                    addBlock(obj);
                }
            }
        }
        return self;
    };
}

- (NSMutableAttributedString *(^)(NSRange))range {
    return ^ id (NSRange range) {
        [self addAttributesWithRange:range];
        return self;
    };
}

代码在Github上，拙作也望大家路过给个星星，祝大家代码越写越好。