如何为Custom TableView Cell应用layoutConstraints

Question

我需要设计自定义单元格，如下面的nslayoutconstraints，通过程序化的方式使用可视化格式语言以及constraintswithitem。任何帮助都会很感激。

`/ *初始化并指定产品名称* /         productName = [[UILabel alloc] init];         productName.font = [UIFont fontWithName：@＆＃34; HelveticaNeue＆＃34;尺寸：17.0f];         self.productName.lineBreakMode = NSLineBreakByWordWrapping;         self.productName.numberOfLines = 0;         productName.translatesAutoresizingMaskIntoConstraints = NO;         [self.contentView addSubview：productName];

    /* Intialize and assign Product Option */
    productOption=[[UILabel alloc]init];
    productOption.translatesAutoresizingMaskIntoConstraints=NO;
    productOption.font=[UIFont fontWithName:@"HelveticaNeue" size:13.0f];
    productOption.textColor=[UIColor colorWithRed:128/255.0f green:128/255.0f blue:128/255.0f alpha:1.0f]; /* 808080 */
    [self.contentView addSubview:productOption];

    /* Intialize and assign Product Image */
    productImageView=[[UIImageView alloc]init];
    productImageView.translatesAutoresizingMaskIntoConstraints=NO;
    productImageView.clipsToBounds=YES;
    productImageView.contentMode=UIViewContentModeScaleAspectFill;
    productImageView.layer.cornerRadius = 22.5;
    productImageView.layer.masksToBounds = YES;
    productImageView.layer.borderColor =[UIColor whiteColor].CGColor;
    productImageView.layer.borderWidth = 1;
    [self.contentView addSubview:productImageView];

    /* Intialize and assign List icon Image */
    listIconImage=[[UIImageView alloc]init];
    listIconImage.translatesAutoresizingMaskIntoConstraints=NO;
    listIconImage.image=[UIImage imageNamed:@"right-arrow.png"];
    [self.contentView addSubview:listIconImage];


   [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productImageView
                                                                 attribute:NSLayoutAttributeTop
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.contentView
                                                                 attribute:NSLayoutAttributeTop
                                                                multiplier:1.0
                                                                  constant:7]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:productImageView
                                                                 attribute:NSLayoutAttributeLeft
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.contentView
                                                                 attribute:NSLayoutAttributeLeft
                                                                multiplier:1
                                                                  constant:11.5]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productImageView
                                                                 attribute:NSLayoutAttributeWidth
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:nil
                                                                 attribute:NSLayoutAttributeWidth
                                                                multiplier:1.0
                                                                  constant:45]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productImageView
                                                                 attribute:NSLayoutAttributeHeight
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:nil
                                                                 attribute:NSLayoutAttributeHeight
                                                                multiplier:1.0
                                                                  constant:45]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productName
                                                                 attribute:NSLayoutAttributeLeading
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.productImageView
                                                                 attribute:NSLayoutAttributeTrailing
                                                                multiplier:1.0
                                                                  constant:10]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productName
                                                                 attribute:NSLayoutAttributeTop
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.contentView
                                                                 attribute:NSLayoutAttributeTop
                                                                multiplier:1.0
                                                                  constant:5]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productOption
                                                                 attribute:NSLayoutAttributeLeading
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.productImageView
                                                                 attribute:NSLayoutAttributeTrailing
                                                                multiplier:1.0
                                                                  constant:10]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.productOption
                                                                 attribute:NSLayoutAttributeTop
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.productName
                                                                 attribute:NSLayoutAttributeBottom
                                                                multiplier:1.0
                                                                  constant:5]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.listIconImage
                                                                 attribute:NSLayoutAttributeRight
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.contentView
                                                                 attribute:NSLayoutAttributeRight
                                                                multiplier:1.0
                                                                  constant:-15.0f]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.listIconImage
                                                                 attribute:NSLayoutAttributeHeight
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:nil
                                                                 attribute:NSLayoutAttributeHeight
                                                                multiplier:1.0
                                                                  constant:20.0f]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.listIconImage
                                                                 attribute:NSLayoutAttributeWidth
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:nil
                                                                 attribute:NSLayoutAttributeWidth
                                                                multiplier:1.0
                                                                  constant:11.0f]];

    [self.contentView addConstraint:[NSLayoutConstraint constraintWithItem:self.listIconImage
                                                                 attribute:NSLayoutAttributeCenterY
                                                                 relatedBy:NSLayoutRelationEqual
                                                                    toItem:self.contentView
                                                                 attribute:NSLayoutAttributeCenterY
                                                                multiplier:1.0
                                                                  constant:0]];  `

上面是我用来创建这个Design的代码。现在我正在努力学习如何在tableviewcontroller中获得动态高度。当我进入heightForRowAtIndexPath时，它总是返回0。

谢谢＆amp;问候 Sam.P

Answer 1

你应该设置tableView.rowHeight = UITableViewAutomaticDimension并提供tableView.estimatedRowHeight = 68.0f（估计高度，不必是准确的）; 更多信息在以下链接： SO Link