1 自定义键盘的高度自定义有两种

一种是用约束，约束无法自定义高度，系统会给默认高度的

self.testView.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([NSLayoutConstraint.init(item: self.testView, attribute: NSLayoutConstraint.Attribute.height, relatedBy: NSLayoutConstraint.Relation.equal, toItem: self.testView, attribute: NSLayoutConstraint.Attribute.height, multiplier: 1, constant: cacheCG?.height ?? 200)])
        
        self.textField.inputView = self.testView

一种是用frame 布局， 可以自定义高度完全自己掌控

//
//  ViewController.swift
//  TestDemoKey
//
//  Created by Mac on 2023/3/22.
//

import UIKit

import SnapKit
class ViewController: UIViewController {
    @IBOutlet weak var textField: UITextField!
    var testView: UIView = UIView.init()
    var testViewH: UIView = UIView.init()
    var cacheCG: CGRect?
    var oldConst: [NSLayoutConstraint] = []
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        let tap = UITapGestureRecognizer.init(target: self, action: #selector(self.tapClick))
        textField.addGestureRecognizer(tap)
        NotificationCenter.default.addObserver(self, selector: #selector(self.willShow(notifi:)), name: UIResponder.keyboardWillShowNotification, object: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(self.willHide(notifi:)), name: UIResponder.keyboardWillHideNotification, object: nil)
        let testView1: UIView = .init()
        testView1.backgroundColor = .blue
        self.testView.addSubview(testView1)
        testView1.snp.makeConstraints { make in
            make.left.top.right.equalTo(0)
            make.bottom.equalTo(-30)
        }
        self.oldConst = self.testView.constraints
    }

    @objc  func willHide(notifi: Notification) {
        
       
     }
    @objc  func willShow(notifi: Notification) {
        if self.textField.inputView == nil {
            let value = notifi.userInfo?["UIKeyboardBoundsUserInfoKey"] as? NSValue
            cacheCG = value?.cgRectValue
            print("notifi ===1 \(value?.cgRectValue)")
        } else {
            let value = notifi.userInfo?["UIKeyboardBoundsUserInfoKey"] as? NSValue
            print("notifi ===2 \(value?.cgRectValue)")
        }
        
     }
    
   @objc  func tapClick() {
       self.textField.inputView = nil
       self.textField.inputAccessoryView = nil
       self.textField.reloadInputViews()
       self.textField.becomeFirstResponder()
    }
    @IBAction func texBtnClick(_ sender: Any) {
        if self.textField.inputView != nil {
            self.tapClick()
            return
        }
        testView.backgroundColor = .red
        
        
        
        
        print("notifi === frame === \(cacheCG?.height ?? 200 + 38) === \(self.testView.constraints)")
//        为了每次都可以自定义高度请这样写
        self.testView.bounds = cacheCG ?? CGRect.init(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: cacheCG?.height ?? 200)
//        self.testView.removeConstraints(self.testView.constraints)
        self.testView.translatesAutoresizingMaskIntoConstraints = true
//        self.testView.constraints.forEach { item in
//            print("item == \(item.firstItem) \(item.secondItem) == \(item.firstAttribute == .height)  \(item.secondAttribute == .height)")
//            if  item.firstAttribute == .height || item.secondAttribute == .height {
//                self.testView.removeConstraint(item)
//            }
//        }
        self.testView.removeConstraints(self.testView.constraints)
        self.testView.addConstraints(self.oldConst)
        self.textField.inputView = self.testView
        
        
        self.textField.reloadInputViews()
        self.textField.becomeFirstResponder()
    }
    
}