使用NSRange的问题:索引越界

Question

我正在尝试检测我的字符串中的网站URL,然后做一些归属字符串,如粗体等.

我的正则表达式定义为:

static NSRegularExpression *websiteRegularExpression;
static inline NSRegularExpression * WebsiteRegularExpression() {
    if (!websiteRegularExpression) {
        websiteRegularExpression = [[NSRegularExpression alloc] initWithPattern:@"\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|!:,.;]*[A-Z0-9+&@#/%=~_|]" 
                                                                        options:NSRegularExpressionCaseInsensitive 
                                                                          error:nil];
    }

    return websiteRegularExpression;
}

这是我列举的地方:

 -(void)setBodyText
    {
        __block NSRegularExpression *regexp = nil;    
        bodyLabel.delegate = self;
        [self.bodyLabel setText:@"http://www.google.com" afterInheritingLabelAttributesAndConfiguringWithBlock:^NSAttributedString *(NSMutableAttributedString *mutableAttributedString) {

            NSRange stringRange = NSMakeRange(0, [mutableAttributedString length]);

            regexp = WebsiteRegularExpression ();
            NSRange nameRange = [regexp rangeOfFirstMatchInString:[mutableAttributedString string] options:0 range:stringRange];
            UIFont *boldSystemFont = [UIFont boldSystemFontOfSize:18.0]; 
            CTFontRef boldFont = CTFontCreateWithName((CFStringRef)boldSystemFont.fontName, boldSystemFont.pointSize, NULL);
            if (boldFont) {
                [mutableAttributedString addAttribute:(NSString *)kCTFontAttributeName value:(id)boldFont range:nameRange];
                CFRelease(boldFont);
            }

            [mutableAttributedString replaceCharactersInRange:nameRange withString:[[[mutableAttributedString string] substringWithRange:nameRange] uppercaseString]];
            return mutableAttributedString;
        }];

        regexp = WebsiteRegularExpression();
        NSRange linkRange = [regexp rangeOfFirstMatchInString:self.bodyLabel.text options:0 range:NSMakeRange(0, [bodyLabel.text length])];
        [self.bodyLabel addLinkToURL:nil withRange:linkRange];
    }

我收到错误:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSCFString substringWithRange:]: Range or index out of bounds'

我怎么解决？

Answer 1

在调用substringWithRange之前检查nameRange的内容.如果正则表达式不匹配,则rangeOfFirstMatchInString的返回值将为

{NSNotFound,0}

NSNotFound定义为NSIntegerMax,因此您可以想象为什么此值可能超出mutableAttributedString的范围.

更新评论

所以要检查substringWithRange的结果:

if (nameRange.location == NSNotFound)
    // didn't match the WebsiteRegularExpression() do something else