_UIButtonBarStackView：当sentFirstResponder发送时打破约束 [英] _UIButtonBarStackView: breaking constraint when becomeFirstResponder sent

问题描述

从一个文本域跳转到另一个文本域时，得到：

  translatesAutoresizingMaskIntoConstraints）
（
 < NSAutoresizingMaskLayoutConstraint：0x6040002806e0 UIKeyboardAssistantBar：0x7f986d40d020.height == 0>，
< NSLayoutConstraint：0x60400008ece0 _UIButtonBarStackView：0x7f986d4041c0.top == UIKeyboardAssistantBar：0x7f986d40d020.top>，
< NSLayoutConstraint ：0x60400008ed30 UIKeyboardAssistantBar：0x7f986d40d020.bottom == _UIButtonBarStackView：0x7f986d4041c0.bottom> 中，
 的< NSLayoutConstraint：0x60400009f220 _UIButtonBarButton：0x7f986d438480.height == UILayoutGuide：0x6040005b5ee0.height> 中，
 的< NSLayoutConstraint ：0x60400008e1a0 _UIButtonBarStackView：0x7f986d4041c0.bottom == UILayoutGuide：0x6040005b5ee0.bottom + 9>，
< NSLayoutConstraint：0x60400008e100 UILayoutGuide：0x6040005b5ee0.top == _UIButtonBarStackView：0x7f986d4041c0.top + 10>
） 
 
将尝试通过bre恢复aking约束
< NSLayoutConstraint：0x60400008e1a0 _UIButtonBarStackView：0x7f986d4041c0.bottom == UILayoutGuide：0x6040005b5ee0.bottom + 9> 
 
在UIViewAlertForUnsatisfiableConstraints上创建一个符号断点，以便在调试器中捕获它。 
< UIKit / UIView.h>中列出的UIView上的UIConstraintBasedLayoutDebugging类别中的方法也可能有所帮助。 
  

在模拟器中测试，不要使用设备。键盘上

我的超级简单代码触发违约：

   - （BOOL）textFieldShouldReturn： （UITextField *）textField 
 {
 [textField resignFirstResponder]; 
 
 if（textField.tag> 0）{
 
 UITextField * nextTextField = [self.view viewWithTag：textField.tag + 1]; 
 [nextTextField becomeFirstResponder]; 
} 
 
返回YES; 
} 
  

解决方案

这个警告让我恼火很长一段时间我通过清空 inputAssistantItem <上的 leadingBarButtonGroups 和 trailingBarButtonGroups 发现了两行'hack' / code> UITextField上的属性：

  inputAssistantItem.leadingBarButtonGroups = [] 
 inputAssistantItem.trailingBarButtonGroups = [ ] 
  

这可以在调用时控制UIKeyboardAssistantBar AutoLayout警告

  becomeFirstResonder（）
  

此处有更多信息： https://developer.apple.com/documentation/uikit/uitextinputassistantitem

Apple的特定说明：

要完全隐藏快捷方式，请将leadingBarButtonGroups和trailingBarButtonGroups属性设置为nil。

When jumping from one textfield to an other, get this:

translatesAutoresizingMaskIntoConstraints) 
(
    "<NSAutoresizingMaskLayoutConstraint:0x6040002806e0 UIKeyboardAssistantBar:0x7f986d40d020.height == 0>",
    "<NSLayoutConstraint:0x60400008ece0 _UIButtonBarStackView:0x7f986d4041c0.top == UIKeyboardAssistantBar:0x7f986d40d020.top>",
    "<NSLayoutConstraint:0x60400008ed30 UIKeyboardAssistantBar:0x7f986d40d020.bottom == _UIButtonBarStackView:0x7f986d4041c0.bottom>",
    "<NSLayoutConstraint:0x60400009f220 _UIButtonBarButton:0x7f986d438480.height == UILayoutGuide:0x6040005b5ee0.height>",
    "<NSLayoutConstraint:0x60400008e1a0 _UIButtonBarStackView:0x7f986d4041c0.bottom == UILayoutGuide:0x6040005b5ee0.bottom + 9>",
    "<NSLayoutConstraint:0x60400008e100 UILayoutGuide:0x6040005b5ee0.top == _UIButtonBarStackView:0x7f986d4041c0.top + 10>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x60400008e1a0 _UIButtonBarStackView:0x7f986d4041c0.bottom == UILayoutGuide:0x6040005b5ee0.bottom + 9>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

Testing in simulator, do not get on device. Something wrong with shortcuts bar over keyboard1?

My super easy code triggers breaking constraint:

-(BOOL)textFieldShouldReturn:(UITextField*)textField
{
    [textField resignFirstResponder];

    if (textField.tag > 0) {

        UITextField *nextTextField = [self.view viewWithTag:textField.tag+1];
        [nextTextField becomeFirstResponder];
    }

    return YES;
}

解决方案

This warning has annoyed me for quite some time. I discovered a two-line 'hack' by emptying leadingBarButtonGroups and trailingBarButtonGroups on the inputAssistantItem property on the UITextField:

inputAssistantItem.leadingBarButtonGroups = []
inputAssistantItem.trailingBarButtonGroups = []

This controls the UIKeyboardAssistantBar AutoLayout warnings when calling

becomeFirstResonder()

More info here: https://developer.apple.com/documentation/uikit/uitextinputassistantitem

Specific note from Apple:

To hide shortcuts altogether, set the leadingBarButtonGroups and trailingBarButtonGroups properties to nil.

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