作为iOS整个项目的核心App delegate,随着项目的逐渐变大,会变得越来越臃肿,一不小心代码就过了千行.
大型项目的App delegate体积会大到什么程度呢?我们可以参考下国外2亿多月活的Telegram的 App delegate.是不是吓一跳,4千多行.看到这样的代码是不是很想点击左上角的x.
是时候该给App delegate解耦了,目标:
每个功能的配置或者初始化都分开,各自做各自的事情.App delegate要做到只需要调用就好了.
下面来谈谈如何利用两种设计模式实现:
1.命令模式
命令模式: 发送方发送请求,然后接收方接受请求后执行,但发送方可能并不知道接受方是谁，执行的是什么操作,这样做的好处是发送方和接受方完全的松耦合，大大提高程序的灵活性.
1. 定义好协议,把相关初始化配置代码分类
protocol Command {
func execute()
}
struct InitializeThirdPartiesCommand: Command {
func execute() {
// 第三方库初始化代码
}
}
struct InitialViewControllerCommand: Command {
let keyWindow: UIWindow
func execute() {
// 根控制器设置代码
}
}
struct InitializeAppearanceCommand: Command {
func execute() {
// 全局外观样式配置
}
}
struct RegisterToRemoteNotificationsCommand: Command {
func execute() {
// 远程推送配置
}
}
2. 管理者
final class StartupCommandsBuilder {
private var window: UIWindow!
func setKeyWindow(_ window: UIWindow) -> StartupCommandsBuilder {
self.window = window
return self
}
func build() -> [Command] {
return [
InitializeThirdPartiesCommand(),
InitialViewControllerCommand(keyWindow: window),
InitializeAppearanceCommand(),
RegisterToRemoteNotificationsCommand()
]
}
}
3. App delegate调用
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
StartupCommandsBuilder()
.setKeyWindow(window!)
.build()
.forEach { $0.execute() }
return true
}
使用命令模式的好处是,如果要添加新的配置,设置完后只要加在StartupCommandsBuilder中就可以了.App delegate中不需要添加任何内容.
但这样做只能将didFinishLaunchingWithOptions中的代码解耦,App delegate中的其他方法怎样解耦呢?
2.组合模式
组合模式: 可以将对象组合成树形结构来表现"整体/部分"层次结构. 组合后可以以一致的方法处理个别对象以及组合对象.
这边我们给App delegate每个功能模块都设置一个子类,每个子类可以根据所需定义App delegate的方法.
1. 每个子模块实现各自的功能
// 推送
class PushNotificationsAppDelegate: AppDelegateType {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
print("推送配置")
return true
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
print("推送相关代码...")
}
// 其余方法
}
// 外观样式
class AppearanceAppDelegate: AppDelegateType {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
print("外观样式配置")
return true
}
}
// 控制器处理
class ViewControllerAppDelegate: AppDelegateType {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
print("根控制器设置代码")
return true
}
}
// 第三方库
class ThirdPartiesConfiguratorAppDelegate: AppDelegateType {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
print("第三方库初始化代码")
return true
}
func applicationDidEnterBackground(_ application: UIApplication) {
print("ThirdPartiesConfiguratorAppDelegate - applicationDidEnterBackground")
}
func applicationDidBecomeActive(_ application: UIApplication) {
print("ThirdPartiesConfiguratorAppDelegate - applicationDidBecomeActive")
}
}
2. 管理者
typealias AppDelegateType = UIResponder & UIApplicationDelegate
class CompositeAppDelegate: AppDelegateType {
private let appDelegates: [AppDelegateType]
init(appDelegates: [AppDelegateType]) {
self.appDelegates = appDelegates
}
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
appDelegates.forEach { _ = $0.application?(application, didFinishLaunchingWithOptions: launchOptions) }
return true
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
appDelegates.forEach { _ = $0.application?(application, didRegisterForRemoteNotificationsWithDeviceToken: deviceToken) }
}
func applicationDidEnterBackground(_ application: UIApplication) {
appDelegates.forEach { _ = $0.applicationDidEnterBackground?(application)
}
}
func applicationDidBecomeActive(_ application: UIApplication) {
appDelegates.forEach { _ = $0.applicationDidBecomeActive?(application)
}
}
}
3. App delegate调用
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
let appDelegate = AppDelegateFactory.makeDefault()
enum AppDelegateFactory {
static func makeDefault() -> AppDelegateType {
return CompositeAppDelegate(appDelegates: [
PushNotificationsAppDelegate(),
AppearanceAppDelegate(),
ThirdPartiesConfiguratorAppDelegate(),
ViewControllerAppDelegate(),
]
)
}
}
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
_ = appDelegate.application?(application, didFinishLaunchingWithOptions: launchOptions)
return true
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
appDelegate.application?(application, didRegisterForRemoteNotificationsWithDeviceToken: deviceToken)
}
func applicationDidBecomeActive(_ application: UIApplication) {
appDelegate.applicationDidBecomeActive?(application)
}
func applicationDidEnterBackground(_ application: UIApplication) {
appDelegate.applicationDidEnterBackground?(application)
}
}
在App delegate解耦中相比命令模式,使用组合模式的可自定义程度会更高一点.
本文收录于 SwiftTips
