UIView с автоматической компоновкой, получить его размер

Ответ 1

sizeToFit - неправильный API для использования, если вы используете автозапуск.

Правильный api для использования для автоотключения UIView systemLayoutSizeFittingSize:, скорее всего, проходит UILayoutFittingCompressedSize. Это вернет CGSize, который является минимальным размером, который может связать представление с указанными ограничениями.

Отметьте эту ссылку

EDIT: в ответ на дополнительный код, который был опубликован...

Я никогда раньше не использовал библиотеку Masonry, но это было аккуратно!

UILabels предоставить intrinsicContentSize, который достаточно велик, чтобы отображать их текст. Чтобы рассчитать этот размер для многострочного текста, метка должна знать одно измерение, которое будет фиксировано, и это размер требуемой ширины с помощью свойства preferredMaxLayoutWidth. Если вы не указали значение preferredMaxLayoutWidth (по умолчанию 0), метка вычисляет собственный размер содержимого AS IF, если он выкладывает одну строку текста.

В вашем коде вы никогда не устанавливаете метку preferredMaxLayoutWidth, поэтому любой макет, выполняемый автозапуском, который полагается на intrinsicContentSize метки, не будет тем, что вы ожидаете.

Я взял ваш код и переработал его в новом примере, который вы можете копировать/вставлять в подкласс чистого представления:

#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 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 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 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 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 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 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 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 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

И, здесь вывод из системыLayoutSizeFittingSize, когда ограничения все работают красиво:

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

Ответ 2

Если я понимаю вас, проблема заключается в том, что динамический размер представления или представлений динамически зависит от прокрутки, когда они представляют собой подпрограммы ScrollView. Вот и все, у меня была эта проблема, и ее можно решить, даже не беспокоясь о размере контента.

Вот ссылка на техническую ноту от Apple под названием "UIScrollView и Autolayout" здесь

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

В примечании легко найти источник, который подробно описывает два подхода к решению этой проблемы. Надеюсь, это поможет, это действительно помогло мне.

Кроме того, если вы пытаетесь выполнить итерацию в коллекции подпрограмм внутри вашего ScrollView, прочитайте эту статью и пример, опять же, ясное объяснение с кодом.

Программирование Apeth IOS 6, глава 20. Прокрутка видов в строке:

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

Ответ 3

Вы пробовали KVO?

в viewDidLoad добавить наблюдателя:

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

затем добавьте этот метод:

- (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));
        }
    }
}

это должно печатать фрейм вашего contentView, если для него установлено нечто большее, чем CGSize(1,1)