Swift3.0 4步解决键盘弹出收起时，视图跟随自动布局(XIB || SnapKit)

 

Swift3.0 4步解决键盘弹出收起时，视图跟随自动布局(XIB || SnapKit)

(写作不易，转载请注明出处)

在点击TextField键盘弹出时，会遮挡视图比如影响到输入或则是登录按钮，非常影响用户体验！

思路：

1、将要移动的视图统一放在一个View里，方便统一移动

2、保存要改变的约束（ps：我是用xib布局的，我是直接把要改变的约束拖到Controller中：bottomViewTopConstraint）,如果是Snapkit布局，则定义一个属性保存即可！

3、在ViewDidLoad中注册通知中心，监听键盘弹起(UIKeyboardWillShow)、隐藏(UIKeyboardWillHide)两种状态；

3、计算要弹起的高度

4、改变约束

 

 1 import UIKit
 2
 3 class WYLoginViewController: WYBaseViewController, UITextFieldDelegate {
 4 
 5     // 使用XIB自动布局的约束
 6     @IBOutlet weak var bottomViewTopConstraint: NSLayoutConstraint!
 7     
 8     override func viewDidLoad() {
 9         super.viewDidLoad()
10 
11         // 注册通知中心，监听键盘弹起的状态
12         NotificationCenter.default.addObserver(self,selector: #selector(WYLoginViewController.keyboardWillChange(_:)),name: .UIKeyboardWillShow, object: nil)
13 
14         // 注册通知中心，监听键盘回落的状态
15         NotificationCenter.default.addObserver(self,selector: #selector(WYLoginViewController.keyboardWillHiden(_:)),name: .UIKeyboardWillHide, object: nil)
16     }
17     
18     deinit {
19
20         // 移除通知中心
21         NotificationCenter.default.removeObserver(self)
22     }
23     
24     // 键盘将要显示
25     func keyboardWillChange(_ notification: Notification) {
26         if let userInfo = notification.userInfo,
27             let value = userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue,
28             let duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? Double,
29             let curve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? UInt {
30             
31             // 获取键盘的高度
32             let frame = value.cgRectValue
33             let intersection = frame.intersection(self.view.frame)
34             // 计算指定视图的底部坐标Y到ViewController‘Bottom的高度
35             let sureButtonBottomOriginY = 64.0 + sureButton.frame.origin.y + sureButton.frame.size.height
36 
37             // 计算差值，即要移动的值
38             let dValue = CGFloat(intersection.height - self.view.frame.size.height + sureButtonBottomOriginY)
39 
40             // 赋值给约束 = 原始值 - 差值
41             bottomViewTopConstraint.constant =  64 - dValue
42 
43             // 刷新约束
44             UIView.animate(withDuration: duration, delay: 0.0,options: UIViewAnimationOptions(rawValue: curve), animations: { _ in
45                 
46                 self.view.layoutIfNeeded()
47             
48             }, completion: nil)
49 
50         }
51     }
52     
53     // 键盘将要隐藏
54     func keyboardWillHiden(_ notification: Notification) {
55         if let userInfo = notification.userInfo,
56             let value = userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue,
57             let duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? Double,
58             let curve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? UInt {
59             
60             let frame = value.cgRectValue
61             let intersection = frame.intersection(self.view.frame)
62 
63             // 如果键盘的高度 == 0， 约束的值直接等于原来的值
64             if intersection.height == 0 {
65                 
66                 bottomViewTopConstraint.constant = 64
67                 
68             } else {
69                 
70             }
71             
72             // 刷新视图
73             UIView.animate(withDuration: duration, delay: 0.0,options: UIViewAnimationOptions(rawValue: curve), animations: { _ in
74                 
75                 self.view.layoutIfNeeded()
76                 
77             }, completion: nil)
78             
79         }
80     }
81     
82     // 点击空白处注销第一响应，键盘回落
83     override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
84         
85         view.endEditing(true)
86     }
87     
88     // TextFieldDelegate 点击Return按钮注销第一响应，键盘回落
89     func textFieldShouldReturn(_ textField: UITextField) -> Bool {
90         
91         textField.resignFirstResponder()
92         
93         return true
94     }
95     
96 }