iOS初学知识点积累

1.控价相对于父控件居中：
点击Align按钮，选择Horizontally in Container 为水品居中，Vertically in Container为竖直居中
2.多个同级控件居中：
同时选中多个控件，点击Align按钮，选中Horizontal Centers相对于水平线居中，Vertical Centers竖直线居中，Baselines基线居中。
3.storyboard的controller和代码controller关联：
在storyboard中创建一个VC，新建一个swift文件导入UIKit继承UIViewController，点击VC顶部三个图标的最左边的，查看属性中的Custom Class选中创建的ViewController类即完成关联。
4.将SVC(Storyboard View Controller)中的控件关联到CVC(Code ViewController):
控件关联：点击两个环的按钮进入到代码和界面同时显示的方式，选中SVC中的控件按control键，拖动到代码区，在弹出框中填写名字connet即可
事件关联：选中控件，点击向右的箭头在下面Touch up Inside右侧的圆圈，拖到代码区域，填写名称connect即可。
关联失败处理：
关闭Xcode
shift+command+G弹出框，复制目录~/Library/Developer/XCode/DerivedData，进入后删除以项目名为开头的文件夹
打开Xcode即可
4.代码控制页面跳转
使用segue方式：选中源SVC中的控制器图标，右键拖动Show Detail到目标SVC就生成了一个segue,选中后点属性图标设置Identifier属性，在代码中调用self.performSegue(withIdentifier: "xxxx", sender: sender.self)
5.访问网络

//post
        let parameters: Parameters = [
            "email":"fangdean@yeah.net",
            "password":"123456"
        ]
        Alamofire
            .request("http://169.254.175.202:8888/user/user/login", method: .post , parameters: parameters)
            .responseJSON {(dataResponse) in
                if let json = dataResponse.result.value {
                    print("json: \(json)")
                }
            }
//get
        Alamofire
            .request("http://169.254.175.202:8888/user/user/login?email=fangdean@yeah.net&password=123456")
            .responseJSON {(dataResponse) in
                if let json = dataResponse.result.value {
                    print("json: \(json)")
                }
            }
//获取String为
        Alamofire
            .request("http://169.254.200.61:8888/user/user/login", method: .post , parameters: parameters)
            .responseString(completionHandler: {(response : DataResponse<String>) in
                switch response.result {
                case .success(let value):
                    print("返回字符串：\(value)")
                    break
                case .failure(let error):
                    print("error msg: \(error.localizedDescription)")
                    break
                }
            })

6.弹出对话框：

        let alertView = UIAlertView();
        alertView.title = "登陆信息";
        alertView.message = "邮箱为：\(txtEmail.text!) 密码为：\(txtPassword.text!)";
        alertView.addButton(withTitle: "OK");
        alertView.show();

7.定义数据Model：
继承Codable，不要赋值

import UIKit
class User: Codable {
    var id:Int64
    var name:String
    var email:String
    var password:String
    var loginState:Int
    var machineNum:Int
    var updateTime:Int64
}

8.导入第三方库：
新建Podfile文件：

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'
use_frameworks!
target 'MiniLife-swift' do
    pod 'Alamofire', '~> 4.7'
    pod 'Moya', '~> 11.0'
end

安装配置文件中的库：
pod install
关闭xcode，点击xxx.xcworkspace打开xcode，发现已经引入pod
9.使用cocoaPods

//显示镜像地址
gem sources -l
//移除镜像地址
gem sources --remove https://rubygems.org/
//设置镜像地址
gem sources -a https://ruby.taobao.org/
//安装cocoapods
sudo gem install cocoapods
//查看库是否可用
pod search AFNetworking
//升级cocospods库
pod repo update

10.安装Ruby环境

//列出Ruby环境列表
rvm list known
//安装环境
rvm install 2.4.1
//把某个环境作为默认Ruby环境
rvm use 2.4.1 --default

11.JSON转Codable:
解析类型必须一一对应，否则识别不了，字段可为空要用Optional类型

//嵌套Codable
import Foundation
struct ResponseEntity: Codable {
    struct User: Codable {
        var id:Int64
        var name:String
        var email:String
        var password:String
        var loginState:Int!
        var machineNum:String!
        var updateTime:Int64!
    }
    var content: User
    var code: Int
    var msg: String
}

        let jsonString = "{\"content\":{\"id\":1,\"name\":\"房德安\",\"email\":\"fangdean@yeah.net\",\"password\":\"123456\",\"loginState\":0,\"machineNum\":\"0\",\"updateTime\":0},\"code\":1,\"msg\":\"登录成功\"}"
        guard let jsonData = jsonString.data(using: .utf8) else {
            print("JOSN字符串转JSON对象失败")
            return
        }
        guard let obj = try? JSONDecoder().decode(ResponseEntity.self, from: jsonData) else {
            print("JSON对象转Model失败")
            return
        }
        print("msg:\(obj.msg)")
        print("code:\(obj.code)")
        print("name:\(obj.content.name)")

12.泛型模板类：可以使用泛型，字段页可以为空(要用!)，类型不能错

//外层类
import Foundation
struct ResponseBean<T>: Codable where T: Codable {
    var content: T
    var code: Int
    var msg: String
}
//内层类
import Foundation
struct User: Codable {
    var id:Int64
    var name:String
    var email:String
    var password:String
    var loginState:Int
    var machineNum:String
    var updateTime:Int64
}

13.最终Alamofire+JSON+Codable网络JSON解析为Model

        Alamofire
            .request("http://169.254.200.61:8888/user/user/login", method: .post , parameters: parameters)
            .responseString(completionHandler: {(response : DataResponse<String>) in
                switch response.result {
                case .success(let value):
                    print("返回字符串：\(value)")
                    guard let jsonData = value.data(using: .utf8) else {
                        print("JOSN字符串转JSON对象失败")
                        return
                    }
                    guard let obj = try? JSONDecoder().decode(ResponseBean<User>.self, from: jsonData) else {
                        print("JSON对象转Model失败")
                        return
                    }
                    print("msg:\(obj.msg)")
                    print("code:\(obj.code)")
                    print("name:\(obj.content.name)")
                    break
                case .failure(let error):
                    print("error msg: \(error.localizedDescription)")
                    break
                }
            })

14.数据库：Core Data
新建项目时选择Use Core Data，就会生成一个.xcdatamodeld的文件
打开次文件AddEntity,+ Attributes来添加表，右侧属性栏设置表名和Model名
不需要创建新的类，系统就会生成对应的Model类
使用先导入import CoreData

//1.增
        //获取管理的数据上下文对象
        let app = UIApplication.shared.delegate as! AppDelegate
        let context = app.persistentContainer.viewContext
        //创建TUser对象
        let tuser = NSEntityDescription.insertNewObject(forEntityName: "TUser", into: context) as! TUser
        tuser.id = user.id
        tuser.name = user.name
        tuser.password = user.password
        tuser.email = user.email
        tuser.loginState = 1
        tuser.machineNum = user.machineNum
        tuser.updateTime = user.updateTime
        do {
            //保存
            try context.save()
            print("保存成功")
            self.performSegue(withIdentifier: "login_to_main", sender: sender.self)
        } catch {
            print("保存失败")
        }
//2.查
        let email = "fangdean@yeah.net"
        let password = "123456"
        //获取管理的数据上下文对象
        let app = UIApplication.shared.delegate as! AppDelegate
        let context = app.persistentContainer.viewContext
        //查询条件
        let fetchRequest = NSFetchRequest<TUser>(entityName: "TUser")
        fetchRequest.fetchLimit = 1
        fetchRequest.fetchOffset = 0
        let predicate = NSPredicate(format: "email = %@ and password = %@ and loginState = 1", email,password)
        fetchRequest.predicate = predicate
        do {
            let fetchedObjects = try context.fetch(fetchRequest)
            //查出之后显示数据
            if fetchedObjects.count > 0 {
                let obj = fetchedObjects[0]
                print("用户已登录")
                print("name:\(obj.name!),\(obj.updateTime)")
            } else {
                print("用户未登录")
            }
        } catch {
            print("查询失败")
        }
//3.改
//查出之后
            let fetchedObjects = try context.fetch(fetchRequest)
            if fetchedObjects.count > 0 {
                let obj = fetchedObjects[0]
                obj.updateTime = 11111
                try context.save()
            } else {
                print("用户未登录")
            }
//4.删:查出之后
            let fetchedObjects = try context.fetch(fetchRequest)
            if fetchedObjects.count > 0 {
                let obj = fetchedObjects[0]
                context.delete(obj)
                try context.save()
            } else {
                print("用户未登录")
            }

15.使用三层泛型嵌套：

struct ResponseBean<T>: Codable where T: Codable {
    var content: T!
    var code: Int
    var msg: String
}
struct ResponseListBean<K>: Codable where K: Codable {
    var content:[K]!
    var totalNum:Int64
    var totalPage:Int64
    var pageSize:Int64
}
struct Category: Codable {
    var id:Int64!
    var parentId:Int64!
    var userId:Int64!
    var name:String!
    var orderNum:Int32!
    var updateTime:Int64!
}
//转换
guard let obj = try? JSONDecoder().decode(ResponseBean<ResponseListBean<Category>>.self, from: jsonData) else {
    print("JSON对象转Model失败")
    return
}

16.使用Core Data的NSFetchRequest时，参数如果为数值型需要封装为NSNumber类型

let predicate = NSPredicate(format: "parentId = 0 and userId = %@", NSNumber(value: userId!))

17.页面跳转时传递数据：
在目标Controller中定义一个变量
在源Controller中实现prepare方法
当执行performSegue()方法之前会执行此方法
在目标Controller中直接使用赋值的变量

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let controller = segue.destination as! GoodsController
        controller.parentId = parentClickId
    }

18.代码segue返回:

self.presentingViewController?.dismiss(animated: true, completion: nil)

19.UILabel控件根据内容确定行数：Label属性的Lines设为0即可