用NSTextAttachment替换NSString的出现次数

Question

我有一个UITextView，并且我想使用NSTextAttachment替换一些特定的字符串为特定的图片。我可以将图像附件插入到UITextView中，并且我有一个方法，可以从文本视图的属性文本中返回一个NSString，该字符串将附件替换为特定的NSString：

-(NSString*)getStringFromAttributedString{ 
__block NSString *str = self.attributedText.string; // Trivial String representation
__block NSMutableString *string = [NSMutableString new]; // To store customized text

[self.attributedText enumerateAttributesInRange:NSMakeRange(0, self.attributedText.length) options:0 usingBlock:^(NSDictionary *attributes, NSRange range, BOOL *stop){     
    // enumerate through the attributes
    NSString *v;   
    NSObject *x = [attributes valueForKey:@"NSAttachment"];  
    if(x){ // YES= This is an attachment       
        v = [Fuctions getObjectTag:x];     
        if(v == nil){
            v=@"";
        }
    }else{
        v = [str substringWithRange:range]; // NO=This is a text block.
    }  
    // append value to string
    [string appendString:v];
}];
return string;
}

现在我需要一个方法，它可以从NSString返回一个NSAttributedString，并将某些字符串替换为图像附件，类似于这样，但我无法使其正常工作。

-(NSMutableAttributedString*)getAttributedStringFromString:(NSString*)string{

    // create NSMutableAttributedString from NSString in input
    NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc] initWithString:string]; 
    // create the attachment with image
    NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
    textAttachment.image = [UIImage imageNamed:@"myImageName.png"];
    textAttachment.bounds = (CGRect) {0, -2, textAttachment.image.size};
    // create NSMutableAttributedString with image attachment
    NSMutableAttributedString *attrStringWithImage = [[NSAttributedString attributedStringWithAttachment:textAttachment] mutableCopy];

    // here I'd like to replace all occurrences of a string (":D" this string for example) with my NSMutableAttributedString with image attachment).

    return string;
}

我该如何做？

谢谢，希望我已经解释清楚了。

- lubilis

---

请查看replaceCharactersInRange:withAttributedString:方法。您可以使用NSRegularExpression或其他“查找”方法在字符串示例中查找“：D”。 - Larme

我不需要检测编辑，因为我的TextView是不可编辑的，但attributedText是动态的。 - lubilis

Answer 1

这是我的工作解决方案：

-(NSMutableAttributedString*)getEmoticonStringFromString:(NSString*)string{

NSMutableAttributedString *final = [NSMutableAttributedString new]; //To store customized text
NSInteger len = [string length];
unichar buffer[len];
[string getCharacters:buffer range:NSMakeRange(0, len)];

for(int i = 1; i < len; i++) {
    if(buffer[i-1] == ':' && buffer[i] == 'D'){

        NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc] initWithString:string];

        NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
        textAttachment.image = [Functions scaleImage:[UIImage imageNamed:@"myImageName"] toSize:CGSizeMake(18.0f, 18.0f)];
        textAttachment.bounds = (CGRect) {0, -2, textAttachment.image.size};

        NSMutableAttributedString *attrStringWithImage = [[NSAttributedString attributedStringWithAttachment:textAttachment] mutableCopy];

        NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init] ;
        [paragraphStyle setAlignment:NSTextAlignmentLeft];
        [paragraphStyle setLineSpacing:2.0f];
        [attrString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [attrString length])];

        [final insertAttributedString:attrStringWithImage atIndex:final.length];

        i++;
    }else{

        [final insertAttributedString:[[NSAttributedString alloc] initWithString:[NSString stringWithFormat:@"%c", buffer[i-1]]] atIndex:final.length];
        if(i == len-1){

            [final insertAttributedString:[[NSAttributedString alloc] initWithString:[NSString stringWithFormat:@"%c", buffer[i]]] atIndex:final.length];
        }
    }
}
return final;

}

- lubilis