确定UILabel中截断的字符数

Question

我有一个UILabel,我想确定UILabel截断的字符数.
使用下面的代码,我可以确定它是否UILabel只有1行

int numberOfTruncatedCharacter = 0;
NSString *text = @"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s";

NSArray  *words = [text componentsSeparatedByString:@" "];
NSString *newStr = @"";
for (NSString *word in words) {
    NSString *statement = [NSString stringWithFormat:@"%@ %@",newStr, word];
    CGSize size = [statement sizeWithAttributes:@{NSFontAttributeName: self.aboutLabel.font}];

    if(size.width < self.aboutLabel.bounds.size.width){
        newStr = [NSString stringWithFormat:@"%@ %@",newStr, word];
    }else{
        numberOfTruncatedCharacter++;
    }
    NSLog(@"%@ | %f | %f",word,size.width,self.aboutLabel.bounds.size.width);
}
NSLog(@"number of truncated character = %d",numberOfTruncatedCharacter);

它工作正常,这是日志

2016-05-27 10:02:44.642 EarCrush[2284:42690] Lorem | 32.622070 | 355.000000
2016-05-27 10:02:44.642 EarCrush[2284:42690] Ipsum | 64.345703 | 355.000000
2016-05-27 10:02:44.642 EarCrush[2284:42690] is | 74.243164 | 355.000000
2016-05-27 10:02:44.643 EarCrush[2284:42690] simply | 107.138672 | 355.000000
2016-05-27 10:02:44.643 EarCrush[2284:42690] dummy | 145.644531 | 355.000000
2016-05-27 10:02:44.643 EarCrush[2284:42690] text | 165.952148 | 355.000000
2016-05-27 10:02:44.644 EarCrush[2284:42690] of | 177.978516 | 355.000000
2016-05-27 10:02:44.644 EarCrush[2284:42690] the | 195.854492 | 355.000000
2016-05-27 10:02:44.645 EarCrush[2284:42690] printing | 235.004883 | 355.000000
2016-05-27 10:02:44.646 EarCrush[2284:42690] and | 255.429688 | 355.000000
2016-05-27 10:02:44.647 EarCrush[2284:42690] typesetting | 309.921875 | 355.000000
2016-05-27 10:02:44.648 EarCrush[2284:42690] industry. | 353.134766 | 355.000000
2016-05-27 10:02:44.649 EarCrush[2284:42690] Lorem | 385.756836 | 355.000000
2016-05-27 10:02:44.649 EarCrush[2284:42690] Ipsum | 384.858398 | 355.000000
2016-05-27 10:02:44.650 EarCrush[2284:42690] has | 372.202148 | 355.000000
2016-05-27 10:02:44.650 EarCrush[2284:42690] been | 379.218750 | 355.000000
2016-05-27 10:02:44.650 EarCrush[2284:42690] the | 371.010742 | 355.000000
2016-05-27 10:02:44.651 EarCrush[2284:42690] industry's | 401.171875 | 355.000000
2016-05-27 10:02:44.651 EarCrush[2284:42690] standard | 397.431641 | 355.000000
2016-05-27 10:02:44.652 EarCrush[2284:42690] dummy | 391.640625 | 355.000000
2016-05-27 10:02:44.652 EarCrush[2284:42690] text | 373.442383 | 355.000000
2016-05-27 10:02:44.653 EarCrush[2284:42690] ever | 375.844727 | 355.000000
2016-05-27 10:02:44.653 EarCrush[2284:42690] since | 379.541016 | 355.000000
2016-05-27 10:02:44.653 EarCrush[2284:42690] the | 371.010742 | 355.000000
2016-05-27 10:02:44.654 EarCrush[2284:42690] 1500s | 383.374023 | 355.000000
2016-05-27 10:02:44.654 EarCrush[2284:42690] number of truncated character = 13

问题是当我UILabel有多行时,我将代码更改为

if(size.width < self.aboutLabel.bounds.size.width * numberOfLines){

但是它无法正确计算.我想也许当UILabel有多行时,它会包含断行符

任何想法来解决它.任何帮助或建议将非常感谢.

Answer 1

您正在检查宽度，但需要检查高度。

查看此开源代码，了解 TTTAttributedLabel 如何使用 CoreText 来了解何时添加“...”字符。

https://github.com/TTTAttributedLabel/TTTAttributedLabel/blob/master/TTTAttributedLabel/TTTAttributedLabel.m

看一下drawframesetter:attributedstring:textrange:inrect:context:方法

您还可以更改开源并公开“...”的位置