UITableViewCell子视图不符合Autolayout约束

Question

我正在绘制一个相当简单的自定义UITableViewCell - 左侧的缩略图,右侧的名称和链接标签.我希望我的名字和链接标签是单行的,如果文本超出单元格的宽度,则在尾部截断.我很确定我正确地添加了约束,但我的名字和链接标签不会尊重它们.

这就是运行iOS 8的iPhone 4S上的单元格外观:

在我的代码中,我将名称和链接标签的10点尾随约束添加到superview(单元格contentView),然而,请注意,即使在横向,iOS似乎也不遵守约束.

有人能告诉我我做错了什么吗？这是我整个单元格的代码.我以编程方式创建视图,并且在表视图单元格的初始化程序中具有Autolayout约束.

#import "PopularWikiCell.h"

// Models
#import "Wiki.h"

// Pods
#import "UIImageView+AFNetworking.h"

// Constants
static const CGFloat kPadding = 10;
static const CGFloat kImageSize = 100;
const CGFloat kPopularWikiCellHeight = kImageSize + kPadding * 2;

@interface PopularWikiCell ()

@property (nonatomic, strong) UIImageView *thumbnailView;
@property (nonatomic, strong) UILabel *nameLabel;
@property (nonatomic, strong) UILabel *linkLabel;

@end

@implementation PopularWikiCell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    if (self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
        // Initialise the subviews.
        _thumbnailView = [[UIImageView alloc] init];
        _thumbnailView.contentMode = UIViewContentModeScaleAspectFill;
        _thumbnailView.clipsToBounds = YES;

        _nameLabel = [[UILabel alloc] init];
        _nameLabel.backgroundColor = [UIColor blueColor];
        _nameLabel.numberOfLines = 1;
        _nameLabel.lineBreakMode = NSLineBreakByTruncatingTail;
        _nameLabel.text = @"Name";

        _linkLabel = [[UILabel alloc] init];
        _linkLabel.backgroundColor = [UIColor redColor];
        _linkLabel.text = @"Link";
        _linkLabel.numberOfLines = 1;
        _linkLabel.lineBreakMode = NSLineBreakByTruncatingTail;

        // Add the subviews.
        [self.contentView addSubview:_thumbnailView];
        [self.contentView addSubview:_nameLabel];
        [self.contentView addSubview:_linkLabel];

        _thumbnailView.translatesAutoresizingMaskIntoConstraints = NO;
        _nameLabel.translatesAutoresizingMaskIntoConstraints = NO;
        _linkLabel.translatesAutoresizingMaskIntoConstraints = NO;
        self.contentView.translatesAutoresizingMaskIntoConstraints = NO;

        // Add the layout constraints.

        NSDictionary *metrics = @{@"kPadding" : @(kPadding),
                                  @"kImageSize" : @(kImageSize)};
        NSDictionary *views = @{@"thumbnailView" : _thumbnailView,
                                @"nameLabel" : _nameLabel,
                                @"linkLabel" : _linkLabel};

        NSArray *constraints = @[@"H:|-kPadding-[thumbnailView(kImageSize)]-kPadding-[nameLabel]-kPadding-|",
                                 @"H:[thumbnailView]-kPadding-[linkLabel]-kPadding-|",
                                 @"V:|-kPadding-[nameLabel]-0-[linkLabel]",
                                 @"V:|-kPadding-[thumbnailView(kImageSize)]"];

        [self.contentView addConstraintsFromVisualFormatStrings:constraints
                                                        options:0
                                                        metrics:metrics
                                                          views:views];
    }
    return self;
}

- (void)setWiki:(Wiki *)wiki
{
    _wiki = wiki;

    self.thumbnailView.image = nil;
    self.thumbnailView.backgroundColor = [UIColor darkGrayColor];
    __weak typeof(self) weakSelf = self;
    [self.thumbnailView setImageWithURLRequest:[NSURLRequest requestWithURL:wiki.thumbnailURL]
                              placeholderImage:nil
                                       success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
                                           __strong typeof(self) strongSelf = weakSelf;
                                           strongSelf.thumbnailView.image = image;
                                           strongSelf.thumbnailView.backgroundColor = [UIColor whiteColor];
                                       }
                                       failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {

                                       }];

    self.nameLabel.text = wiki.name;
    self.linkLabel.text = wiki.URL;

    [self.contentView setNeedsLayout];
}

- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
    [super setSelected:selected animated:animated];

    // Selection removes all background colors so re-set it.
    [self resetSubviewBackgroundColors];

    [self.contentView setNeedsLayout];
}

- (void)setHighlighted:(BOOL)highlighted animated:(BOOL)animated
{
    [super setHighlighted:highlighted animated:animated];

    // Highlighing removes all background colors so re-set it.
    [self resetSubviewBackgroundColors];

    [self.contentView setNeedsLayout];
}

- (void)resetSubviewBackgroundColors
{
    if (self.thumbnailView.image) {
        self.thumbnailView.backgroundColor = [UIColor whiteColor];
    } else {
        self.thumbnailView.backgroundColor = [UIColor darkGrayColor];
    }
}

@end

Answer 1

这个问题隐藏在

self.contentView.translatesAutoresizingMaskIntoConstraints = NO;

删除此代码可以解决您的问题.

如果您不希望将自动调整掩码变为约束 - 请为cell.contentView设置您需要的约束.