动态的UILabel内UIScrollView的高度与自动布局 [英] Dynamic UILabel height inside UIScrollView with Autolayout

问题描述

我使用的自动布局与的UIScrollView 显示从对象的某些属性。我从Web服务dinamically下载此信息。滚动视图具有恒定的宽度（因为我不希望有一个垂直滚动行为）及其子视图尊重这个宽度与一组约束，但我不能增加的UILabel 的高度动态。

I am using autolayout with UIScrollView to show some attributes from an object. I download this information dinamically from web service. The scrollview has a constant width (because I don't want to have a vertical scroll behavior) and its subviews respect this width with a group of constraints, but I can't to increase the UILabel's height dynamically.

我code一切，我用 viewDidLoad中选择创建子视图...

I code everything and I use viewDidLoad selector to create subviews...

- (void)viewDidLoad {
    [super viewDidLoad];
    .
    .
    .

    UILabel *descriptionLabel = [[UILabel alloc] initWithFrame:CGRectZero];
    descriptionLabel.translatesAutoresizingMaskIntoConstraints = NO;
    descriptionLabel.numberOfLines = 0;
    descriptionLabel.lineBreakMode = NSLineBreakByWordWrapping;
    descriptionLabel.opaque = YES;
    descriptionLabel.backgroundColor = [UIColor clearColor];
    descriptionLabel.textColor = [UIColor whiteColor];
    descriptionLabel.textAlignment = NSTextAlignmentRight;
    descriptionLabel.font = [UIFont appetitoMediumItalicFontWithSize:15.0f];
    descriptionLabel.text = NSLocalizedStringFromTable(@"APT_DISH_DETAIL_DESCRIPTION", @"DishDetail", @"Etiqueta que contiene la descripción del platillo");
    [descriptionLabel setContentHuggingPriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
    [self.detailContentScrollView addSubview:descriptionLabel];
    self.descriptionLabelS = descriptionLabel;

    .
    .
    .
}

您可以观看 self.detailContentScrollView 变量，这是一个 IBOulet 从视图控制器的笔尖创建的。

You can watch the self.detailContentScrollView variable, this is an IBOulet created from view controller's nib.

然后我使用 updateConstraints 选择...

Then I use the updateConstraints selector...

- (void)updateConstraints {
[super updateConstraints];
// This dictionary has more variables, ok
NSDictionary *viewsDict = @{@"dish_description_label": self.descriptionLabelS};
.
.
.

[self.descriptionLabelS setContentHuggingPriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
[self.detailContentScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[view1][dish_description_label]-[view2][view3][view4]-|" options:0 metrics:nil views:viewsDict]];

.
.
.
}

最后，当我收到Web服务的信息，我送 sizeToFit 的的UILabel 选择和 layoutIfNeeded 从滚动视图。但我的的UILabel 从来没有新的内容调整大小本身。我在做什么错了？

and finally, when I receive the web service's info, I send sizeToFit's UILabel selector and layoutIfNeeded from the scrollview. But my UILabel never resizes itself with the new content. What am I doing wrong?

推荐答案

UIScrollView的内容大小与自动布局动态更新，也许你只是必须执行以下操作

UIScrollView content size is updated dynamically with autolayout, maybe you only must do the following

- (void) setupScroll
{
    [_scrollView setTranslatesAutoresizingMaskIntoConstraints:NO];
    [_contentView setTranslatesAutoresizingMaskIntoConstraints:NO];

    [_scrollView addSubview:_contentView];

    NSArray *horizontal = [NSLayoutConstraint constraintsWithVisualFormat:@"|[_contentView]|"
                                                                  options:0
                                                                  metrics:nil
                                                                    views:NSDictionaryOfVariableBindings(_contentView)];
    NSArray *vertical = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_contentView]|"
                                                                options:0
                                                                metrics:nil
                                                                  views:NSDictionaryOfVariableBindings(_contentView)];

    [_scrollView addConstraints:horizontal];
    [_scrollView addConstraints:vertical];

    UIView *mainView = self.view;
    horizontal = [NSLayoutConstraint constraintsWithVisualFormat:@"|[_contentView(==mainView)]|"
                                                         options:0
                                                         metrics:nil
                                                           views:NSDictionaryOfVariableBindings(_contentView, mainView)];

    [mainView addConstraints:horizontal];
}

在哪里_contentView是你的UILabel（如果你已经把一个更复杂的视图层次视图上的容器），并self.view是控制器视图（或其他）。希望这有助于也是：<一href=\"http://stackoverflow.com/questions/16843633/ios-autolayout-with-uiscrollview-why-does-content-view-of-scroll-view-not-fill\">iOS自动布局用的UIScrollView？为什么滚动视图的内容视图不填滚动视图 ....

另外，不要忘记建立您的UILabel preferredMaxLayoutWidth

Also don't forget to establish your UILabel preferredMaxLayoutWidth

干杯！

这篇关于动态的UILabel内UIScrollView的高度与自动布局的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！