当最后一行显示不全时,需求有时候需要改变省略号的位置,系统并未提供,但我们可以通过 coreText 拿到每行的文字,然后将最后一行文字在指定的地方截断,再拼接省略号,话不多说,贴代码:
FXBreakLineLable.h
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface FXBreakLineLable : UILabel
- (void)setLineBreakByTruncatingLastLine;
@end
NS_ASSUME_NONNULL_END
FXBreakLineLable.m
#import "FXBreakLineLable.h"
#import <CoreText/CoreText.h>
@implementation FXBreakLineLable
- (void)setLineBreakByTruncatingLastLine {
if ( self.numberOfLines <= 0 ) {
return;
}
NSArray *separatedLines = [self getSeparatedLinesArray];
NSMutableString *limitedText = [NSMutableString string];
if ( separatedLines.count >= self.numberOfLines ) {
for (int i = 0 ; i < self.numberOfLines; i++) {
if ( i == self.numberOfLines - 1) {
FXBreakLineLable *lastLineLabel = [[FXBreakLineLable alloc]initWithFrame:CGRectMake(0, 0, self.frame.size.width - 100, MAXFLOAT)];
lastLineLabel.font = self.font;
lastLineLabel.text = separatedLines[self.numberOfLines - 1];
NSArray *subSeparatedLines = [lastLineLabel getSeparatedLinesArray];
NSString *lastLineText = [subSeparatedLines firstObject];
NSInteger lastLineTextCount = lastLineText.length;
if ([[lastLineText substringFromIndex:(lastLineTextCount - 1)] isEqualToString:@"\n"]) {
lastLineText = [lastLineText substringToIndex:(lastLineText.length - 1)];
lastLineTextCount = lastLineTextCount - 1;
}
[limitedText appendString:[NSString stringWithFormat:@"%@...",[lastLineText substringToIndex:lastLineTextCount]]];
} else {
[limitedText appendString:separatedLines[i]];
}
}
} else {
[limitedText appendString:self.text];
}
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.lineSpacing = 7;
NSMutableAttributedString *attText = [[NSMutableAttributedString alloc] initWithString: (( separatedLines.count >= self.numberOfLines ) ? [limitedText stringByAppendingString:@" 全文"] : limitedText)
attributes:@{
NSForegroundColorAttributeName : self.textColor,
NSFontAttributeName : self.font,
NSParagraphStyleAttributeName : style
}];
if ( separatedLines.count >= self.numberOfLines ) {
[attText addAttributes:@{
NSFontAttributeName : [UIFont boldSystemFontOfSize:14.0],
NSForegroundColorAttributeName : [UIColor blackColor]
} range:NSMakeRange(attText.length - 2, 2)];
}
self.attributedText = attText;
}
- (NSArray *)getSeparatedLinesArray {
NSString *text = [self text];
UIFont *font = [self font];
CTFontRef myFont = CTFontCreateWithName((__bridge CFStringRef)([font fontName]), [font pointSize], NULL);
NSMutableAttributedString *attStr = [[NSMutableAttributedString alloc] initWithString:text];
[attStr addAttribute:(NSString *)kCTFontAttributeName value:(__bridge id)myFont range:NSMakeRange(0, attStr.length)];
CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)attStr);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width - 55, 100000));
CTFrameRef frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, NULL);
NSArray *lines = (__bridge NSArray *)CTFrameGetLines(frame);
NSMutableArray *linesArray = [[NSMutableArray alloc]init];
for (id line in lines) {
CTLineRef lineRef = (__bridge CTLineRef )line;
CFRange lineRange = CTLineGetStringRange(lineRef);
NSRange range = NSMakeRange(lineRange.location, lineRange.length);
NSString *lineString = [text substringWithRange:range];
[linesArray addObject:lineString];
}
return (NSArray *)linesArray;
}
@end
当前需求是在后端显示 “全文” 二字,其他需求实现需要稍作修改;
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