iphone - 具有自动布局的 UIView，获取他的大小

Question

我有一个 UIView 女巫以编程方式填充内容。此 UIView 中的布局是使用自动布局进行的。

这个 View 需要是一个UIScrollView的 subview ，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，它是 UIView 创建的:[[UIView alloc] initWithFrame:CGRectMake(self.layoutMargin, self.layoutMargin, 1024 - self.layoutMargin*2, 100 )]);

这个 self.content View 对我来说只是容器，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);

This is Log: Size: 17713.000000 0.000000

它看起来像:http://d.pr/i/Rxku

Answer 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:最有可能传递 UILayoutFittingCompressedSize。这将返回一个 CGSize，它是可以使用指定约束绑定(bind) View 的最小大小。

检查 this链接

编辑:响应已发布的附加代码...

我从未使用过 Masonry图书馆之前，但它很整洁!

UILabels 提供一个足够大的 intrinsicContentSize 来显示它们的文本。为了计算多行文本的大小，标签需要知道一个固定的尺寸，即通过 preferredMaxLayoutWidth 属性获得的所需宽度尺寸。如果您不提供 preferredMaxLayoutWidth 值(默认为 0)，标签将计算固有内容大小，就好像它在布置单行文本一样。

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，你应该能够将它复制/粘贴到一个干净的 viewcontroller 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

并且，当约束全部正常工作时，这是 systemLayoutSizeFittingSize 的输出:

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