UITextVIew在屏幕上不可见

Question

我有以下两个视图：

 let captionTextView: UITextView = {
    let textField = UITextView(frame: CGRectMake(0,0, 250, 100))
    textField.text = "Enter caption..."
    textField.textColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 1.0)
    textField.editable = true
    textField.backgroundColor = UIColor.blueColor()
    textField.layer.cornerRadius = 5
    textField.layer.borderColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 1.0).CGColor
    textField.layer.borderWidth = 1
    textField.font = UIFont.boldSystemFontOfSize(15)
    return textField
}()

let infoLabel : UILabel = {
    let myLabel = UILabel()
    myLabel.textColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 1.0)
    myLabel.text = "Testing"
    myLabel.font = UIFont.systemFontOfSize(16.0)
    myLabel.textAlignment = NSTextAlignment.Center
    myLabel.adjustsFontSizeToFitWidth = true
    return myLabel
}()

我将以下约束条件添加到我的视图控制器中：

func setupViews() {
    self.view.addSubview(captionTextView)
    self.view.addSubview(infoLabel)
    infoLabel.translatesAutoresizingMaskIntoConstraints = false
    captionTextView.translatesAutoresizingMaskIntoConstraints = false
    self.view.addConstraint(NSLayoutConstraint(item: infoLabel, attribute: .Top, relatedBy: .Equal, toItem: self.view, attribute: .Top, multiplier: 1, constant: 35))
    self.view.addConstraint(NSLayoutConstraint(item: infoLabel, attribute: .Leading, relatedBy: .Equal, toItem: self.view, attribute: .Leading, multiplier: 1, constant: 10))
    self.view.addConstraint(NSLayoutConstraint(item: infoLabel, attribute: .Trailing, relatedBy: .Equal, toItem: self.view, attribute: .Trailing, multiplier: 1, constant: -10))
    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Top, relatedBy: .Equal, toItem: infoLabel, attribute: .Top, multiplier: 1, constant: 35))
    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Leading, relatedBy: .Equal, toItem: self.view, attribute: .Leading, multiplier: 1, constant: 10))
    self.view.addConstraint(NSLayoutConstraint(item: captionTextView, attribute: .Trailing, relatedBy: .Equal, toItem: self.view, attribute: .Trailing, multiplier: 1, constant: -10))


}

标签在我想要的位置正确显示。textView 在屏幕上根本看不到。如果我将其类型更改为 textField 或 UILabel，则可以正常工作，因此我不知道缺少哪些约束条件。我漏掉了什么？

- Alk

---

你需要为你的textView设置高度约束。 - iSashok

这不是由框架指定的吗？ - Alk

不会像标签一样工作，设置底部或高度。 - Wilson XJ

@mankee 如果删除约束条件会发生什么？那么它会在视图中显示吗？ - thephatp

我按照@WilsonXJ的建议将底部进行设置，问题已解决。 - Alk

Answer 1

由于textView继承自UIScrollView，因此需要为其添加底部锚点。

根据Apple文档： https://developer.apple.com/documentation/uikit/uitextview

- Hanisa Mohamed