键盘出现时，使用自动布局约束移动文本字段 [英] Moving a textfield with auto layout constraints when the keyboard appears

问题描述

我有一个搜索栏文本字段和一个表视图（谷歌自动完成），我想翻译当键盘进入视图。我成功地做到这一点，但是，我得到关于我的约束的警告/错误。我使用自动布局通过故事板在这个视图，并试图禁用/启用约束之前/之后显示/隐藏键盘，但我仍然得到这些错误。我没有正确禁用自动布局？我遵循了 this SO中提供的内容

  override func viewDidLoad（）{
 ... 
 NSNotificationCenter.defaultCenter（）。addObserver （self，selector：Selector（keyboardWillHead：），name：UIKeyboardWillHideNotification，object（objectWithShowNotification，object：nil）
 NSNotificationCenter.defaultCenter（）。addObserver ：nil）
 ... 
} 
 func keyboardWillShow（sender：NSNotification）{
 self.pixieLabel.hidden = true 
 self.searchBar.setTranslatesAutoresizingMaskIntoConstraints 
 self.startingTableView.setTranslatesAutoresizingMaskIntoConstraints（true）
 self.searchBar.frame.origin.y  -  = 150 
 self.startingTableView.frame.origin.y  -  = 150 
} 
 func keyboardWillHide（sender：NSNotification）{
 self.pixieLabel.hidden = false 
 self.searchBar.setTranslatesAutoresizingMaskIntoConstraints（false）
 self.startingTableView.setTranslatesAutoresizingMaskIntoConstraints（false）
 self.searchBar.frame.origin.y + = 150 
 self.startingTableView.frame.origin.y + = 150 
} 
  

>

解决方案代码

  func keyboardWillShow（sender：NSNotification）{
 self.pixieLabel.hidden = true 
 self.seachBarTopConstraint.constant  -  = 150 
 self.searchBar.layoutIfNeeded（）
} 
 func keyboardWillHide（sender：NSNotification）{
 self.pixieLabel。 hidden = false 
 self.seachBarTopConstraint.constant + = 150 
 self.searchBar.layoutIfNeeded（）
} 
  

解决方案

而不是调整框架值，我认为你应该创建 @IBOutlet 引用Interface Builder中的约束，然后在想要对它们进行动画处理时更改这些约束的常量值，到 layoutIfNeeded 。根据我的理解，手动更改视图框架和自动布局的值不会混合。

此外，我不会搞乱 setTranslatesAutoresizingMaskIntoConstraints ，除非您以编程方式添加您的约束，在这种情况下，您最有可能将其设置为 false 。 $ b

I have a search bar text field and a table view (for google auto complete) that I would like to translate up when the keyboard comes into view. I am successfully doing this, however, I am getting warnings/errors about my constraints. I am using auto layout via storyboard on this view and tried to disable/enable the constraints prior to/after showing/hiding the keyboard, but I am still getting these errors. Am I not disabling auto layout correctly? I followed what was given in this SO response.

override func viewDidLoad() {
    ...
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil)
    ...
}
func keyboardWillShow(sender: NSNotification) {
    self.pixieLabel.hidden = true
    self.searchBar.setTranslatesAutoresizingMaskIntoConstraints(true)
    self.startingTableView.setTranslatesAutoresizingMaskIntoConstraints(true)
    self.searchBar.frame.origin.y -= 150
    self.startingTableView.frame.origin.y -= 150
}
func keyboardWillHide(sender: NSNotification) {
    self.pixieLabel.hidden = false
    self.searchBar.setTranslatesAutoresizingMaskIntoConstraints(false)
    self.startingTableView.setTranslatesAutoresizingMaskIntoConstraints(false)
    self.searchBar.frame.origin.y += 150
    self.startingTableView.frame.origin.y += 150
}

Solution Code

func keyboardWillShow(sender: NSNotification) {
    self.pixieLabel.hidden = true
    self.seachBarTopConstraint.constant -= 150
    self.searchBar.layoutIfNeeded()
}
func keyboardWillHide(sender: NSNotification) {
    self.pixieLabel.hidden = false
    self.seachBarTopConstraint.constant += 150
    self.searchBar.layoutIfNeeded()
}

解决方案

Instead of adjusting theframe values, I think you should be creating @IBOutlet references to constraints in Interface Builder and then changing the constant value of those constraints when you want to animate them, followed by a call to layoutIfNeeded. As I understand it, manually changing the values of a view's frame and auto layout don't mix.

Also, I wouldn't mess around with setTranslatesAutoresizingMaskIntoConstraints unless you are adding your constraints programmatically, in which case you're most likely just setting it to false.

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