小编Seb*_*ian的帖子

我正在尝试使用swift以编程方式创建一个简单的tableView,所以我在"AppDelegate.swift"上编写了这段代码:

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)

    var tvc :TableViewController = TableViewController(style: UITableViewStyle.Plain)
    self.window!.rootViewController = tvc

    self.window!.backgroundColor = UIColor.whiteColor()
    self.window!.makeKeyAndVisible()
    return true
    }

基本上我添加了TableViewController创建并添加到窗口.这是TableViewController代码:

class TableViewController: UITableViewController {

init(style: UITableViewStyle) {
    super.init(style: style)
 }

override func viewDidLoad() {
    super.viewDidLoad()
 }

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// #pragma mark - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView?) -> Int {
    return 1
} …

我正在使用CoreData测试swift,我创建了以下代码:

import UIKit
import CoreData

class Contact: NSManagedObject {

    @NSManaged var name: String
    @NSManaged var email: String

    class func execute(){
        let appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
        let context:NSManagedObjectContext = appDel.managedObjectContext!

        let entityDescripition = NSEntityDescription.entityForName("Contact", inManagedObjectContext: context)
        let contact = Contact(entity: entityDescripition!, insertIntoManagedObjectContext: context)

        contact.name = "john Apleesee"
        contact.email = "john@apple.com"

        context.save(nil)

        let fetch:NSFetchRequest = NSFetchRequest(entityName: "Contact")
        var result = context.executeFetchRequest(fetch, error: nil) as [Contact]

        let firstContact = result[0] as Contact  //  <<-- error !

        println("\(firstContact.name)")
        println("\(firstContact.email)")

    }

}

当我跑:

Contact.execute() …

我想UIImageView在里面添加一个动画,UICollectionViewCell所以我想出了这段代码:

    import UIKit

class MainViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {

    var items:[String] = ["one", "two", "three", "four"]

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor(red: 220/255, green: 220/255, blue: 220/255, alpha: 1.0)
        self.view.addSubview(self.collectionView)
    }

    lazy var collectionView:UICollectionView = {
        var cv = UICollectionView(frame: self.view.bounds, collectionViewLayout: self.flowLayout)
        cv.delegate = self
        cv.dataSource = self
        cv.bounces = true
        cv.alwaysBounceVertical = true
        cv.autoresizingMask = UIViewAutoresizing.FlexibleHeight | UIViewAutoresizing.FlexibleWidth
        cv.registerClass(CustomCell.self, forCellWithReuseIdentifier: "cell")
        cv.backgroundColor = UIColor(red: 220/255, green: 220/255, blue: 220/255, alpha: 1.0)
        return …

我开始使用app测试Core Data和iCloud(使用Magical Records).在配置Provisioning Profiles和权利很多麻烦后,应用程序最终运行.一段时间后,应用程序崩溃并抛出此消息::

2012-12-31 03:42:07.079 iCloudTest[252:1103] -[PFUbiquitySafeSaveFile waitForFileToUpload:](268): CoreData: Ubiquity:  <PFUbiquityPeerReceipt: 0x1cd5a420>(0)
permanentLocation: <PFUbiquityLocation: 0x1cd57b30>: /private/var/mobile/Library/Mobile Documents/MA5BADG5AW~com~gazapps~iCloudTest/mobile.4088E03C-763E-5A81-BB1B-64CABAFA73E3/com.gazapps.iCloudTest/v8GumdiUYmkE0aO9iGtPTPHX07qqWk7kRytsQwHKjwU=/receipt.0.cdt
safeLocation: <PFUbiquityLocation: 0x1cd57a80>: /private/var/mobile/Library/Mobile Documents/MA5BADG5AW~com~gazapps~iCloudTest/mobile.4088E03C-763E-5A81-BB1B-64CABAFA73E3/com.gazapps.iCloudTest/v8GumdiUYmkE0aO9iGtPTPHX07qqWk7kRytsQwHKjwU=/mobile.4088E03C-763E-5A81-BB1B-64CABAFA73E3.0.cdt
currentLocation: <PFUbiquityLocation: 0x1cd57a80>: /private/var/mobile/Library/Mobile Documents/MA5BADG5AW~com~gazapps~iCloudTest/mobile.4088E03C-763E-5A81-BB1B-64CABAFA73E3/com.gazapps.iCloudTest/v8GumdiUYmkE0aO9iGtPTPHX07qqWk7kRytsQwHKjwU=/mobile.4088E03C-763E-5A81-BB1B-64CABAFA73E3.0.cdt

kv: (null)

Safe save failed for file, error: Error Domain=NSCocoaErrorDomain Code=512 "The file upload timed out." UserInfo=0x1cd5b7d0 {NSLocalizedDescription=The file upload timed out.}
2012-12-31 03:42:07.083 iCloudTest[252:1103] +[MagicalRecord(ErrorHandling) defaultErrorHandler:](0xe5ac0) Error: The file upload timed out.
2012-12-31 03:42:07.085 iCloudTest[252:1103] +[MagicalRecord(ErrorHandling) defaultErrorHandler:](0xe5ac0) Error Message: The file upload timed out.
2012-12-31 …

是否可以使用不同的数据模型创建两个不同的领域？

例如:defaultRealm将客户端类用作模型,myRealm将使用products类作为模型

我正在尝试创建一个从底部进入屏幕的视图的动画。但第一次它只出现在屏幕上，没有任何动画，然后它就开始正常工作。

这是代码：

struct ContentView: View {
@State private var showView = false
var body: some View {
    ZStack(alignment: .bottom){
        VStack{
            Button("TAP HERE") {
                withAnimation(.spring()) {
                    showView.toggle()
                }
            }
            Spacer()
        }
        if showView {
            RoundedRectangle(cornerRadius: 30)
                .frame(height: UIScreen.main.bounds.height * 0.5)
                .transition(.move(edge: .bottom))
        }
    }
    .edgesIgnoringSafeArea(.bottom)
}

}

这是行为：

我做错了什么？

我正在使用 Xcode 14 beta 5 和 Swift 5

我创建了一个 swift 类来测试字典。所以，我写了下面的代码：

import Foundation

   class MyClass {

    var myFirstDictionary:[String :String]
    var myThirdDictionary:[String :String]?

    init(){
        var mySecondDictionary:[String :String] = [String :String]()
        mySecondDictionary["animal"] = "Monkey"
        mySecondDictionary.updateValue("something", forKey: "SomeKey")

        self.myFirstDictionary = [String :String]()
        addOneThingToSecondDictionary()
        addAnotherThingToSecondDictionary()

        self.myThirdDictionary! = [String :String]()
        addOneThingToThirdDictionary()
        addAnotherThingToThirdDictionary()
    }

    func addOneThingToSecondDictionary(){
        self.myFirstDictionary["animal"] = "Monkey"
    }

    func addAnotherThingToSecondDictionary(){
        self.myFirstDictionary.updateValue("Superman", forKey: "hero")
    }

    func addOneThingToThirdDictionary(){
        self.myThirdDictionary["animal"]! = "Monkey"
    }

    func addAnotherThingToThirdDictionary(){
        self.myThirdDictionary!.updateValue("Superman", forKey: "hero")
    }

  }

所以，我收到了 3 个关于“myThirdDictionary”的错误：

• 在字典初始化编译器中说：找不到接受提供的参数的“init”的重载
• 当我尝试在addOneThingToThirdDictionary() 中添加键/值对时：'[String : String]?' 没有名为“下标”的成员 …

我正在尝试使用 AutoLayout 以编程方式创建 UICollectionView，但我遇到了一些问题。

第一次测试：

在我的第一次尝试中，我创建了一个 UICollectionView 作为 Lazy var 并将其添加到 viewDidLoad 中，如下所示：

lazy var collection: UICollectionView = {
        let cv = UICollectionView()
        cv.translatesAutoresizingMaskIntoConstraints = false
        cv.setCollectionViewLayout(self.flowLayout, animated: true)
        cv.dataSource = self
        cv.delegate = self
        cv.registerClass(MyViewCell.self, forCellWithReuseIdentifier: "cell")
        return cv
}()


override func viewDidLoad() {
        super.viewDidLoad()

        self.view.addSubview(self.collection)
}

这个方法把我带到了这个错误：

由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：“UICollectionView 必须使用非零布局参数进行初始化”

第二次测试：

所以我不得不使用 frame/collectionViewLayout 初始值设定项，我的第二次尝试看起来像这样：

lazy var collection: UICollectionView = {
        let cv = UICollectionView(frame: UIScreen.mainScreen().bounds, collectionViewLayout: self.flowLayout)
        cv.translatesAutoresizingMaskIntoConstraints = false
        cv.setCollectionViewLayout(self.flowLayout, animated: true)
        cv.dataSource = self
        cv.delegate = self …

我正在尝试在 Xcode Playground 上运行这个异步函数：

import Foundation
import PlaygroundSupport

PlaygroundPage.current.needsIndefiniteExecution = true

enum NetworkingError: Error {
    case invalidServerResponse
    case invalidCharacterSet
}

func getJson() async throws -> String {
        let url = URL(string:"https://jsonplaceholder.typicode.com/todos/1")!
        let (data, response) = try await URLSession.shared.data(from: url)
        
        guard let httpResponse = response as? HTTPURLResponse,
              httpResponse.statusCode == 200 else {
                  throw NetworkingError.invalidServerResponse
              }
        
        guard let result = String(data: data, encoding: .utf8) else {
            throw NetworkingError.invalidCharacterSet
        }
        
        return result
}
    
let result = try! await getJson()
print(result)

我收到此错误消息：

error: ForecastPlayground.playground:27:25: …

我尝试了这个：

    let contact = CNMutableContact()
    contact.namePrefix = data["firstName"] as! String
    contact.nameSuffix = data["lastName"] as! String
    contact.organizationName = data["company"] as! String
    contact.jobTitle = data["jobTitle"] as! String

    let address = CNMutablePostalAddress()
    address.street = data["street"] as! String
    address.city = data["city"] as! String
    address.state = data["state"] as! String
    address.postalCode = data["zipcode"] as! String
    address.country = data["country"] as! String

    contact.postalAddresses = [address]

我收到此错误：

Cannot convert value of type 'CNMutablePostalAddress' to expected element type 'CNLabeledValue<CNPostalAddress>'

所以，我尝试了这个：

let contact = CNMutableContact()
    contact.namePrefix = data["firstName"] as! String
    contact.nameSuffix …