版本记录

版本号	时间
V1.0	2020.11.20 星期五

前言

WidgetKit是iOS14的新的SDK，接下来几篇我们就一起看一下这个专题。感兴趣的可以看下面几篇文章。
1. WidgetKit框架详细解析（一） —— 基本概览（一）
2. WidgetKit框架详细解析（二） —— 一个基于WidgetKit和SwiftUI的简单示例（一）

源码

1. Swift

首先看下工程组织结构

下面就是源码了

1. EmitronWidget.swift

import WidgetKit
import SwiftUI
import Intents

extension FileManager {
  static func sharedContainerURL() -> URL {
    return FileManager.default.containerURL(
      forSecurityApplicationGroupIdentifier: "group.emitron.contents"
    )!
  }
}

let snapshotEntry = WidgetContent(name: "iOS Concurrency with GCD and Operations",
  cardViewSubtitle: "iOS & Swift",
  descriptionPlainText: """
  Learn how to add concurrency to your apps! \
  Keep your app’s UI responsive to give your \
  users a great user experience.
  """,
  releasedAtDateTimeString: "Jun 23 2020 • Video Course (3 hrs, 21 mins)")

//struct Provider: TimelineProvider {
//  public typealias Entry = WidgetContent
//
//  public func snapshot(with context: Context, completion: @escaping (Entry) -> ()) {
//    let entry = snapshotEntry
//    completion(entry)
//  }
//
//  func readContents() -> [Entry] {
//    var contents: [WidgetContent] = []
//    let archiveURL = FileManager.sharedContainerURL().appendingPathComponent("contents.json")
//    print(">>> \(archiveURL)")
//
//    let decoder = JSONDecoder()
//    if let codeData = try? Data(contentsOf: archiveURL) {
//      do {
//        contents = try decoder.decode([WidgetContent].self, from: codeData)
//      } catch {
//        print("Error: Can't decode contents")
//      }
//    }
//    return contents
//  }
//
//  public func timeline(with context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
//    var entries = readContents()
//
//    // Generate a timeline by setting entry dates interval seconds apart,
//    // starting from the current date.
//    let currentDate = Date()
//    let interval = 5
//    for index in 0 ..< entries.count {
//      entries[index].date = Calendar.current.date(byAdding: .second,
//        value: index * interval, to: currentDate)!
//    }
//
//    let timeline = Timeline(entries: entries, policy: .atEnd)
//    completion(timeline)
//  }
//}

struct PlaceholderView : View {
  var body: some View {
    EntryView(model: snapshotEntry)
  }
}

//@main
//struct EmitronWidget: Widget {
//  private let kind: String = "EmitronWidget"
//
//  public var body: some WidgetConfiguration {
//    StaticConfiguration(kind: kind, provider: Provider(), placeholder: PlaceholderView()) { entry in
//      EntryView(model: entry)
//    }
//    .configurationDisplayName("RW Tutorials")
//    .description("See the latest video tutorials.")
//    .supportedFamilies([.systemMedium])
//  }
//}

struct Provider: IntentTimelineProvider {
  public typealias Entry = WidgetContent

  public func snapshot(for configuration: TimelineIntervalIntent, with context: Context, completion: @escaping (Entry) -> ()) {
    let entry = snapshotEntry
    completion(entry)
  }

  func readContents() -> [Entry] {
    var contents: [WidgetContent] = []
    let archiveURL = FileManager.sharedContainerURL().appendingPathComponent("contents.json")
    print(">>> \(archiveURL)")

    let decoder = JSONDecoder()
    if let codeData = try? Data(contentsOf: archiveURL) {
      do {
        contents = try decoder.decode([WidgetContent].self, from: codeData)
      } catch {
        print("Error: Can't decode contents")
      }
    }
    return contents
  }

  public func timeline(for configuration: TimelineIntervalIntent, with context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    var entries = readContents()
    let interval = configuration.interval as! Int

    // Generate a timeline consisting of five entries an hour apart, starting from the current date.
    let currentDate = Date()
    for index in 0 ..< entries.count {
      entries[index].date = Calendar.current.date(byAdding: .second, value: index * interval, to: currentDate)!
    }

    let timeline = Timeline(entries: entries, policy: .atEnd)
    completion(timeline)
  }
}

@main
struct EmitronWidget: Widget {
  private let kind: String = "EmitronWidget"

  public var body: some WidgetConfiguration {
    IntentConfiguration(kind: kind, intent: TimelineIntervalIntent.self, provider: Provider(), placeholder: PlaceholderView()) { entry in
      EntryView(model: entry)
    }
    .configurationDisplayName("RW Tutorials")
    .description("See the latest video tutorials.")
    .supportedFamilies([.systemMedium])
  }
}

2. WidgetContent.swift

import Foundation
import WidgetKit

struct WidgetContent: Codable, TimelineEntry {
  var date = Date()
  let name: String
  let cardViewSubtitle: String
  let descriptionPlainText: String
  let releasedAtDateTimeString: String
}

3. EntryView.swift

import SwiftUI

struct EntryView: View {
  let model: WidgetContent

  var body: some View {
    VStack(alignment: .leading) {
      Text(model.name)
        .font(.uiTitle4)
        .lineLimit(2)
        .fixedSize(horizontal: false, vertical: true)
        .padding([.trailing], 15)
        .foregroundColor(.titleText)
      
      Text(model.cardViewSubtitle)
        .font(.uiCaption)
        .lineLimit(nil)
        .foregroundColor(.contentText)
      
      Text(model.descriptionPlainText)
        .font(.uiCaption)
        .fixedSize(horizontal: false, vertical: true)
        .lineLimit(2)
        .lineSpacing(3)
        .foregroundColor(.contentText)
      
      Text(model.releasedAtDateTimeString)
        .font(.uiCaption)
        .lineLimit(1)
        .foregroundColor(.contentText)
    }
    .background(Color.cardBackground)
    .padding()
    .cornerRadius(6)
  }
}

后记

本篇主要讲述了基于WidgetKit和SwiftUI的简单示例，感兴趣的给个赞或者关注~~~