依次平均分配UILabel的frame

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- (void)setupTitleLabel
{
    for (NSInteger i = 0; i < self.titlesArray.count; i++) {
        UILabel *label = [[UILabel alloc]init];
        label.text = self.titlesArray[i];
        label.tag = i;
        label.backgroundColor = [UIColor orangeColor];
        label.textAlignment = NSTextAlignmentCenter;
        [self.titleScrollView addSubview:label];
        [self.itemLabelArray addObject:label];
        label.userInteractionEnabled = YES;
        UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapGesture:)];
        [label addGestureRecognizer:tap];  
    }   
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    NSInteger count = self.titlesArray.count;
    CGFloat labelX = 0;
    CGFloat labelY = 0;
    CGFloat labelW = 0;
    CGFloat labelH = self.frame.size.height;
    CGFloat kMargin = 20;
    
    for (NSInteger i = 0; i < count; i++) {
        UILabel *lastLabel = i > 0 ? self.itemLabelArray[i - 1] : nil;
        labelX = i == 0 ? kMargin * 0.5 : lastLabel.right + kMargin;
        labelW = [self widthWithStr:self.titlesArray[i]];
        UILabel *titleLabel = self.itemLabelArray[i];
        titleLabel.frame = CGRectMake(labelX, labelY, labelW + 15, labelH);
    }
    // 思想:主要确定的是labelX,和labelW,只考虑第一个label的间隔kMargin * 0.5及其他label的间隔kMargin,剩下的由上一个label的右端 + kMargin为这一个label的labelX
    UILabel *lastLabel = self.itemLabelArray[count - 1];
    self.titleScrollView.contentSize = CGSizeMake(lastLabel.right + kMargin * 0.5, labelH);
    
}

- (CGFloat)widthWithStr:(NSString *)myStr
{
    return  [myStr boundingRectWithSize:CGSizeMake(MAXFLOAT, 20) options:NSStringDrawingUsesLineFragmentOrigin attributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIFont systemFontOfSize:17],NSFontAttributeName, nil] context:nil].size.width;
}

上述代码中lastLabel.right是由UIView+Common的一个category的方法
- (CGFloat)right
{
return self.frame.origin.x + self.frame.size.width;
}
获取的
效果如下