使用 Masonry 配置好约束，再给每个 label 设置好内容（内容确定已经设置），为什么拿到的 label 的宽度是 0

使用Masonry 配置好约束，再给每个label设置好约束和内容（内容确定已经设置），拿到的label的宽度是0。最终label是正常显示的。

这是实现的代码：四个函数从上到下依次调用

//创建labels
- (void)createView
{
    [self.view addSubview:[UIView new]];
    //创建分类选择视图

    classificationScrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, kNavigationBarHeight + kStatusBarHeight, kScreenWidth, kClassificationScrollViewHeight)];
    [self.view addSubview:classificationScrollView];

    classificationScrollView.contentSize = CGSizeMake(2 * kScreenWidth, kClassificationScrollViewHeight);

    classificationScrollView.backgroundColor = [UIColor yellowColor];

    contentView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, contentViewWidth, kClassificationScrollViewHeight)];
    [classificationScrollView addSubview:contentView];

    contentView.backgroundColor = [UIColor redColor];

    classificationScrollView.bounces = NO;

    //创建类别
    labelViewArray = [[NSMutableArray alloc]initWithCapacity:11];

    for (int i = 0; i < classificationArray.count; i++)
    {
        UILabel *labelView = [UILabel new];
        [labelViewArray addObject:labelView];
        [contentView addSubview:labelView];
    }

}

//配置约束
- (void)setAutolayout
{
    [labelViewArray[0] mas_makeConstraints:^(MASConstraintMaker *make)
    {
        make.top.bottom.equalTo(contentView);
        make.left.equalTo(contentView.mas_left).offset(kSpace);
    }];

    [labelViewArray[1] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[0]).mas_right).offset(kSpace);
     }];

    [labelViewArray[2] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[1]).mas_right).offset(kSpace);
     }];

    [labelViewArray[3] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[2]).mas_right).offset(kSpace);

     }];

    [labelViewArray[4] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[3]).mas_right).offset(kSpace);

     }];

    [labelViewArray[5] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[4]).mas_right).offset(kSpace);

     }];

    [labelViewArray[6] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[5]).mas_right).offset(kSpace);

     }];

    [labelViewArray[7] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[6]).mas_right).offset(kSpace);

     }];

    [labelViewArray[8] mas_makeConstraints:^(MASConstraintMaker *make)
     {
         make.top.bottom.equalTo(contentView);
         make.left.equalTo(((UILabel *)labelViewArray[7]).mas_right).offset(kSpace);
        // make.right.equalTo(contentView);

     }];

    [labelViewArray[0] setContentHuggingPriority:UILayoutPriorityDefaultLow forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[1] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[2] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[3] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[4] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[5] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[6] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[7] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
    [labelViewArray[8] setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];


}

//设置每个label的内容
- (void)setArrayViews
{
    for (int i = 0; i < classificationArray.count; i++)
    {
        UILabel *labelView = labelViewArray[i];
        labelView.text = classificationArray[i];
        labelView.textAlignment = NSTextAlignmentCenter;
    }
}

//这个函数里面求每个label的宽度，输出的label的宽度全是0
- (void)resetContentView
{
    NSInteger widthSum = 0;

    for (int i = 0; i < classificationArray.count; i++)
    {
        UILabel *lableView = labelViewArray[i];
        widthSum =  widthSum + lableView.bounds.size.width;
        NSLog(@"%f", lableView.bounds.size.width);
    }

    contentViewWidth = (classificationArray.count + 1) * kSpace + widthSum;

    contentView.bounds = CGRectMake(0, 0, contentViewWidth, kClassificationScrollViewHeight);


}