【问题标题】:UIView with Auto layout, get his size具有自动布局的 UIView,获取他的大小
【发布时间】:2013-07-27 23:04:10
【问题描述】:

我有一个 UIView 女巫以编程方式填充内容。此 UIView 中的布局是使用 Auto-layout 进行的。

这个视图需要是一个UIScrollView的子视图,并且需要垂直滚动。

我有这样的代码:

// self.scrollview is defined in IB and it has constraints to edges (margin:0 0 0 0)

UIView *contentView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 1024, MAXFLOAT)];
[contentView setTranslatesAutoresizingMaskIntoConstraints:YES];

// Then I call some my parser which add subviews to the contentView and layout them using constraints.

[self.scrollview addSubview:contentView];
[contentView setNeedsLayout];
[contentView layoutIfNeeded];

// Now, I need to know height of the contentView to be able to set contentSize to self.scrollview

// 更新

好的,我有这个 UILabel,添加到 self.content,这是 UIView 创建的:[[UIView alloc] initWithFrame:CGRectMake(self.layoutMargin, self.layoutMargin, 1024 - self.layoutMargin*2, 100)]);

这个 self.content 视图对我来说只是一个容器,需要放在一些UIScrollView 中。我需要 self.content 的高度来设置 UIScrollView 的 contentSize。

[self.content setTranslatesAutoresizingMaskIntoConstraints:YES];

[self.content setContentHuggingPriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
[self.content setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];

UILabel *textlabel = [[UILabel alloc] init];
UIFont *font;


font = [UIFont fontWithName:@"InterstatePlus-Regular" size:16];

UIFont *bold;

bold = [UIFont fontWithName:@"InterstatePlus-Bold" size:16];
NSDictionary *style = @{
                        @"$default" : @{NSFontAttributeName  : font},
                        @"b"        : @{NSFontAttributeName  : bold},
                        @"em"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Italic" size:14]},
                        @"h1"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Medium" size:48]},
                        @"h2"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Medium" size:36]},
                        @"h3"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Medium" size:32]},
                        @"h4"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Medium" size:24]},
                        @"h5"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Medium" size:18]},
                        @"h6"       : @{NSFontAttributeName  : [UIFont fontWithName:@"HelveticaNeue-Medium" size:16]}
                        };
[textlabel setNumberOfLines:0];



NSError *error = nil;
NSString *string = @"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing <br>Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type<br> and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.";
NSString *replacedString = [string stringByReplacingOccurrencesOfString:@"<br>" withString:@"\n"];
NSAttributedString *attributedString = [SLSMarkupParser attributedStringWithMarkup:replacedString style:style error:&error];
NSMutableAttributedString *mutAttributedString = [[NSMutableAttributedString alloc] initWithAttributedString:attributedString];

NSInteger strLength = [attributedString length];
NSMutableParagraphStyle *paragraphstyle = [[NSMutableParagraphStyle alloc] init];
[mutAttributedString addAttribute:NSParagraphStyleAttributeName
                            value:paragraphstyle
                            range:NSMakeRange(0, strLength)];

if (mutAttributedString) {
    textlabel.attributedText = mutAttributedString;
}


[textlabel setTranslatesAutoresizingMaskIntoConstraints:NO];

[textlabel setContentHuggingPriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
[textlabel setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];


textlabel.textAlignment = NSTextAlignmentLeft;

[textlabel setTextColor:[UIColor blackColor]];

[textlabel setBackgroundColor:[UIColor clearColor]];
textlabel.lineBreakMode = NSLineBreakByWordWrapping;
[textlabel setNumberOfLines:0];
[self.content addSubview:textlabel];

[textlabel mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.equalTo(self.content.mas_top).with.offset(0); 
    make.right.equalTo(self.content.mas_right).with.offset(0);
    make.height.equalTo(@1200);
    make.left.equalTo(self.content.mas_left).with.offset(0);
}];
[self.containerView addSubview:self.content];
[self.containerView setBackgroundColor:[UIColor redColor]];
[self.content setBackgroundColor:[UIColor yellowColor]];

CGSize s = [self.content systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
NSLog(@"Size: %f %f", s.width, s.height);

这是日志:大小:17713.000000 0.000000

它看起来像:http://d.pr/i/Rxku

【问题讨论】:

  • 所有这些代码都在viewDidLoad中吗?

标签: iphone ios cocoa-touch uiview autolayout


【解决方案1】:

如果您使用自动布局,sizeToFit 是错误的 API。

用于自动布局的正确 api 是 UIView systemLayoutSizeFittingSize:,很可能通过 UILayoutFittingCompressedSize。这将返回一个 CGSize,它是可以将视图与其指定约束绑定的最小尺寸。

查看this链接

编辑:响应发布的附加代码...

我以前从未使用过Masonry 库,但它很整洁!

UILabels 提供一个足以显示其文本的intrinsicContentSize。为了计算多行文本的大小,标签需要知道一个将被固定的尺寸,这就是通过preferredMaxLayoutWidth 属性获得的所需宽度尺寸。如果您不提供 preferredMaxLayoutWidth 值(默认为 0),则标签会计算固有内容大小,因为它正在布置单行文本。

在您的代码中,您永远不会设置标签的 preferredMaxLayoutWidth,因此依赖于标签的 intrinsicContentSize 的自动布局执行的任何布局都不会是您所期望的。

我把你的代码提炼成一个新的例子,你应该可以将它复制/粘贴到一个干净的视图控制器子类中:

#import "Masonry.h"

@interface TSViewController ()
@end

@implementation TSViewController
{
    UIScrollView*   _scrollView;
    UIView*         _containerView;

    UILabel*        _titleLabel;
    UILabel*        _contentLabel;
}

- (void) viewDidLoad
{
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor darkGrayColor];

    // create/configure our scrollview
    _scrollView = [UIScrollView new];
    _scrollView.translatesAutoresizingMaskIntoConstraints = NO;
    _scrollView.backgroundColor = [UIColor scrollViewTexturedBackgroundColor];
    [self.view addSubview: _scrollView];

    // create/configure our container
    _containerView = [UIView new];
    _containerView.translatesAutoresizingMaskIntoConstraints = NO;
    _containerView.backgroundColor = [UIColor yellowColor];
    [_scrollView addSubview: _containerView];

    // create/configure our content - title and content labels
    _titleLabel = [UILabel new];
    _titleLabel.translatesAutoresizingMaskIntoConstraints = NO;
    _titleLabel.numberOfLines = 1;
    _titleLabel.font = [UIFont fontWithName: @"Courier" size: 80];
    _titleLabel.text = @"Lorem Ipsum";
    _titleLabel.backgroundColor = [UIColor lightGrayColor];
    _titleLabel.textAlignment = NSTextAlignmentCenter;
    [_containerView addSubview: _titleLabel];

    _contentLabel = [UILabel new];
    _contentLabel.translatesAutoresizingMaskIntoConstraints = NO;
    _contentLabel.numberOfLines = 0;
    _contentLabel.font = [UIFont fontWithName: @"Courier" size: 40];
    _contentLabel.text = self.loremIpsum;
    [_containerView addSubview: _contentLabel];

    // configure constraints for each view:

    [_scrollView mas_makeConstraints: ^(MASConstraintMaker *make) {

        // glue the scrollview to its superview with a 20 point inset:

        make.top.equalTo( self.view.mas_top ).with.offset( 20 );
        make.left.equalTo( self.view.mas_left ).with.offset( 20 );
        make.right.equalTo( self.view.mas_right ).with.offset( -20 );
        make.bottom.equalTo( self.view.mas_bottom ).with.offset( -20 );
    }];

    [_containerView mas_makeConstraints: ^(MASConstraintMaker *make) {

        // per the iOS 6.0 Release Notes, this is how to use auto-layout for a container view
        // inside a scrollview.  basically, tie the edges of the containerview to the scrollview.
        // http://developer.apple.com/library/ios/#releasenotes/General/RN-iOSSDK-6_0/
        // see section "Here are some notes regarding Auto Layout support for UIScrollView"

        make.top.equalTo( _scrollView.mas_top );
        make.left.equalTo( _scrollView.mas_left );
        make.right.equalTo( _scrollView.mas_right );
        make.bottom.equalTo( _scrollView.mas_bottom );

        // match the width of the containerview to the scrollview width:
        make.width.equalTo( _scrollView.mas_width );

        // match the height of the containerview to the intrinsic height of the contentlabel + 100 points for our fixed height title

        // (this is the magical part.)
        make.height.equalTo( _contentLabel.mas_height ).with.offset( 100 );
    }];

    [_titleLabel mas_makeConstraints:^(MASConstraintMaker *make) {

        // tie the contentlabel edges to the sides of its container:
        make.top.equalTo( _containerView.mas_top ).with.offset(0);
        make.left.equalTo( _containerView.mas_left ).with.offset(0);
        make.right.equalTo( _containerView.mas_right ).with.offset(0);

        // fixed height
        make.height.equalTo( @100 );
    }];

    [_contentLabel mas_makeConstraints:^(MASConstraintMaker *make) {

        // tie top edge to the bottom of our title
        make.top.equalTo( _titleLabel.mas_bottom );

        // tie the remaining edges to the sides of the container:
        make.left.equalTo( _containerView.mas_left );
        make.right.equalTo( _containerView.mas_right );
        make.bottom.equalTo( _containerView.mas_bottom );
    }];
}

- (void) viewWillLayoutSubviews
{
    // perform a scrollview layout so the containerView width will be set
    [_scrollView setNeedsLayout];
    [_scrollView layoutIfNeeded];

    // update the preferred layout width of the content label;
    // this affects the label's intrinsicContentSize and will force our constraints to be recalculated
    CGFloat preferredWidth = _containerView.frame.size.width;
    _contentLabel.preferredMaxLayoutWidth = preferredWidth;


    // we don't need this since the scrollview is fully using autolayout to adjust the content-size.  but just to show that it works:

    CGSize fittingSize = [_containerView systemLayoutSizeFittingSize: UILayoutFittingCompressedSize];

    NSLog( @"container fitting size: %@", NSStringFromCGSize( fittingSize ));
}

- (NSString*) loremIpsum
{
    return @"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing <br>Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type<br> and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.";
}

@end

而且,当约束都正常工作时,这是 systemLayoutSizeFittingSize 的输出:

2013-08-05 15:01:16.309 testLabelConstraints[8265:c07] container fitting size: {721, 6868}

【讨论】:

  • U 使用:CGSize s = [self.mainContentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize]; NSLog(@"尺寸: %f %f", s.width, s.height);我得到: 大小: 5584.000000 0.000000 :(
  • @dormitkon -那么你的约束可能会混淆。您可以尝试一个更简单的案例,并在它工作后重新增加复杂性吗?或者发布更多代码并显示您的约束,以便我们提供帮助。
  • 约束是从一些 XML 布局解析生成的,因此它们可以在页面之间更改。我检查了 autolayouttrace 并且布局很好。 :|
  • 约束可能“很好”,但它们可能允许零高度容器(如您所见)。这意味着约束可以为任何高度为零的容器视图生成“正确”的布局。
  • 也许问题是容器视图? UIScrollView 的子视图中的这个视图(我使用框架,因为我不能在 UISCrollView 中使用自动布局)。
【解决方案2】:

如果我理解你的话,问题是当它们是 ScrollView 的子视图时,获取一个或多个动态大小的视图以正确滚动。就是这样,我遇到了这个问题,甚至不必担心内容大小就可以解决。

这里是 Apple 技术说明的链接,标题为“UIScrollView and Autolayout”

http://developer.apple.com/library/ios/technotes/tn2154/_index.html

注释中的来源很容易理解,其中详细介绍了解决此问题的两种方法。希望这会有所帮助,它真的帮助了我。

此外,如果您尝试遍历 ScrollView 中的子视图集合,请再次阅读这篇文章和示例,用代码进行清晰的解释。

Apeth Programming IOS 6,第 20 章。在此处滚动查看:

http://www.apeth.com/iOSBook/ch20.html

【讨论】:

    【解决方案3】:

    你试过KVO吗?

    viewDidLoad添加观察者:

    [contentView addObserver:self forKeyPath:@"frame" options:NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew | NSKeyValueObservingOptionPrior context:NULL];
    

    然后添加这个方法:

    - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
        if([keyPath isEqualToString:@"frame"]) {
            CGRect oldFrame = CGRectNull;
            CGRect newFrame = CGRectNull;
            if([change objectForKey:@"old"] != [NSNull null]) {
                oldFrame = [[change objectForKey:@"old"] CGRectValue];
            }
            if([object valueForKeyPath:keyPath] != [NSNull null]) {
                newFrame = [[object valueForKeyPath:keyPath] CGRectValue];
            }
            //new size!
            if (newFrame.size.width > 0 && newFrame.size.height > 0) {
                NSLog(@"%@", NSStringFromCGRect(newFrame));
            }
        }
    }
    

    当设置为大于 CGSize(1,1) 时,这应该打印您的 contentView 的框架

    【讨论】:

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