ios - 导致 textview 隐藏的约束

Question

如果我使用文本字段，该对象将出现，但如果我使用 TextView ，该对象不会出现。我相信问题出在我的限制上？

    commentTextView.text = "test text"
    commentTextView.translatesAutoresizingMaskIntoConstraints = false
    commentTextView.backgroundColor = UIColor.redColor()
    commentTextView.font = UIFont.boldSystemFontOfSize(bodyFontSize)
    commentTextView.textColor = UIColor.whiteColor()

    containerView.addSubview(commentTextView)

    let views: [String : AnyObject] = [
        "containerView": containerView,
        "titleLabel": titleLabel,
        "commentTextView": commentTextView,
        "closeButton": closeButton]

    view.addConstraints(
        NSLayoutConstraint.constraintsWithVisualFormat(
            "H:|[containerView]|",
            options: NSLayoutFormatOptions(rawValue: 0),
            metrics: nil,
            views: views))

    view.addConstraints(
        NSLayoutConstraint.constraintsWithVisualFormat(
            "V:|[containerView]|",
            options: NSLayoutFormatOptions(rawValue: 0),
            metrics: nil,
            views: views))

    containerView.addConstraints(
        NSLayoutConstraint.constraintsWithVisualFormat(
            "H:|[titleLabel]|",
            options: NSLayoutFormatOptions(rawValue: 0),
            metrics: nil,
            views: views))

    containerView.addConstraints(
        NSLayoutConstraint.constraintsWithVisualFormat(
            "H:|[commentTextView]|",
            options: NSLayoutFormatOptions(rawValue: 0),
            metrics: nil,
            views: views))

    containerView.addConstraints(
        NSLayoutConstraint.constraintsWithVisualFormat(
            "H:|[closeButton]|",
            options: NSLayoutFormatOptions(rawValue: 0),
            metrics: nil,
            views: views))

    containerView.addConstraints(
        NSLayoutConstraint.constraintsWithVisualFormat(
            "V:|-(>=30)-[titleLabel]-" +
            "[commentTextView]-[closeButton]-(>=10)-|",
            options: NSLayoutFormatOptions(rawValue: 0),
            metrics: nil,
            views: views))

任何有关让我的 TextView 出现的帮助将不胜感激

Answer 1

尝试在 TextView 上设置高度限制:

commentTextView.addConstraint(NSLayoutConstraint(item: commentTextView, 属性: .Height, relatedBy: .Equal, toItem: nil, 属性: .NotAnAttribute, 乘数: 1.0, 常量: 50.0))

文本字段无需显式设置即可知道其高度(至少使用默认边框样式)。 textview 则不然。