问题描述
我正在使用带有 UIScrollView 的自动布局来显示对象的一些属性.我从网络服务动态下载此信息.滚动视图具有恒定宽度(因为我不希望有垂直滚动行为),并且它的子视图通过一组约束尊重这个宽度,但我不能增加 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.
我编写所有代码并使用 viewDidLoad 选择器创建子视图...
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; . . . }
您可以查看 self.detailContentScrollView 变量,这是从视图控制器的 nib 创建的 IBOUlet.
You can watch the self.detailContentScrollView variable, this is an IBOulet created from view controller's nib.
然后我使用 updateConstraints 选择器...
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 服务的信息时,我从滚动视图发送 sizeToFit 的 UILabel 选择器和 layoutIfNeeded.但是我的 UILabel 永远不会用新内容调整自己的大小.我做错了什么?
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 内容大小是通过自动布局动态更新的,或许你只需要做到以下几点
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]; }
其中 _contentView 是您的 UILabel(如果您在视图容器上放置了更复杂的视图层次结构),而 self.view 是控制器视图(或其他任何东西).希望这也有帮助:iOS使用 UIScrollview 自动布局:为什么滚动视图的内容视图不填充滚动视图?....
Where _contentView is your UILabel (If you have a more complex view hierarchy put on a view container) and self.view is the controller view (or anything else). Hope this helps also: iOS Autolayout with UIScrollview: Why does content view of scroll view not fill the scroll view?....
另外别忘了建立你的UILabel preferredMaxLayoutWidth
干杯!