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本节将通过纯代码进行封装自定义View控件，以常用的设置页的item为例，实现UI效果如下：

1、创建SettingView继承自UIView

import UIKitclass SettingView: UIView {}

2、重写 init() 和 required init?(coder: NSCoder) 方法

纯代码创建SettingView会执行到init()，而required init?(coder: NSCoder)则是用于可视化布局时，所以两个方法都必须重写。

import UIKitclass SettingView: UIView {init() {super.init(frame: CGRect.zero)innerInit()}required init?(coder: NSCoder) {super.init(coder: coder)innerInit()}func innerInit() {}}

3、约束设置

当视图加入父视图时，才能进行约束设置，故需要重写 didMoveToSuperview()，并在didMoveToSuperview()方法里面编写约束设置。

import UIKitclass SettingView: UIView {init() {super.init(frame: CGRect.zero)innerInit()}required init?(coder: NSCoder) {super.init(coder: coder)innerInit()}func innerInit() {}/// 当视图加入父视图时 / 当视图从父视图移除时调用override func didMoveToSuperview() {super.didMoveToSuperview()//添加约束}
}

4、完整自定义view代码

//
//  SettingView.swift
//  SnapKitTest
//
//  Created by jin on 2024/8/13.
//import UIKitclass SettingView: UIView {init() {super.init(frame: CGRect.zero)innerInit()}required init?(coder: NSCoder) {super.init(coder: coder)innerInit()}func innerInit(){backgroundColor = .whiteaddSubview(leftImgView)addSubview(rightImgView)addSubview(titleView)}/// 当视图加入父视图时 / 当视图从父视图移除时调用override func didMoveToSuperview() {super.didMoveToSuperview()//添加约束leftImgView.snp.makeConstraints { make inmake.left.equalToSuperview().offset(16)make.centerY.equalToSuperview()make.width.equalTo(20)make.height.equalTo(20)}titleView.snp.makeConstraints { make inmake.left.equalTo(leftImgView.snp.right).offset(16)make.centerY.equalToSuperview()}rightImgView.snp.makeConstraints { make inmake.right.equalToSuperview().offset(-16)make.centerY.equalToSuperview()make.width.equalTo(20)make.height.equalTo(20)}}///左侧图标lazy var leftImgView: UIImageView = {let imageView = UIImageView()imageView.image = UIImage(named: "Setting")return imageView}()///右侧图标lazy var rightImgView: UIImageView = {let imageView = UIImageView()imageView.image = UIImage(named: "Arrow")return imageView}()///标题lazy var titleView: UILabel = {let textView = UILabel()textView.text = "标题"return textView}()
}

5、使用自定义View

view.addSubview(settingView)//添加约束，只有添加当前控件，内部的约束在控件内部就添加了
settingView.snp.makeConstraints { make inmake.top.equalTo(view.safeAreaLayoutGuide.snp.top)make.width.equalToSuperview()make.height.equalTo(55)
}lazy var settingView: SettingView = {let view = SettingView()view.titleView.text = "设置"view.leftImgView.image = UIImage(named: "Setting")return view
}()

6、设置View点击事件

@objc func onSettingClick(recognizer:UITapGestureRecognizer) {print("onSettingClick")
}lazy var settingView: SettingView = {let view = SettingView()view.titleView.text = "设置"view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(onSettingClick(recognizer:))))return view
}()

7、使用自定义View的完整代码

//
//  SettingController.swift
//  SnapKitTest
//
//  Created by jin on 2024/8/13.
//import UIKitclass SettingController: UIViewController {override func viewDidLoad() {super.viewDidLoad()view.backgroundColor = .systemGroupedBackgroundtitle = "设置界面"view.addSubview(settingView)view.addSubview(collectView)//添加约束，只有添加当前控件，内部的约束在控件内部就添加了settingView.snp.makeConstraints { make inmake.top.equalTo(view.safeAreaLayoutGuide.snp.top)make.width.equalToSuperview()make.height.equalTo(55)}collectView.snp.makeConstraints { make inmake.top.equalTo(settingView.snp.bottom).offset(1)make.width.equalToSuperview()make.height.equalTo(55)}}@objc func onSettingClick(recognizer:UITapGestureRecognizer) {print("onSettingClick")}@objc func onCollectClick(recognizer:UITapGestureRecognizer) {print("onCollectClick")}lazy var settingView: SettingView = {let view = SettingView()view.titleView.text = "设置"view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(onSettingClick(recognizer:))))return view}()lazy var collectView: SettingView = {let view = SettingView()view.titleView.text = "收藏"view.leftImgView.image = UIImage(named: "Setting")view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(onCollectClick(recognizer:))))return view}()}

至此，一个简单的纯代码封装自定义View控件便实现了。