获取UILabel 的行数

/**
 获取行数
self 代表UILabel
 */
-(NSInteger)getLabelLineNum{
    CGFloat labelHeight = [self sizeThatFits:CGSizeMake(self.frame.size.width, MAXFLOAT)].height;
    NSNumber *count = @((labelHeight) / self.font.lineHeight);
    return [count integerValue];
}