簡介
在iOS工程中,AppDelegate往往會有上千行,甚至幾千行,這樣就會給維護AppDelegate帶來諸多麻煩。比方說,老板想在出現HomeViewController之前彈出廣告並停頓幾秒,這樣你就要加入插入廣告的邏輯;又比方說,老板想在開始做個請求,判斷某個開關是否打開。這樣就會在AppDelegate中插入很多相關的不相關的代碼。
在AppDelegate中,- (BOOL)application:(UIApplication )application didFinishLaunchingWithOptions:(NSDictionary )launchOptions是“Tells the delegate when the application has launched and may have additional launch options to handle.”,即在app開始運行時會調用裡面的方法。在didFinishLaunchingWithOptions中,我們往往會渲染window,注冊第三方監控庫,加入基本頁面跳轉邏輯。
下面是一個常見項目中的didFinishLaunchingWithOptions:
// objective-c語言 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { if (!([ADeanUserDataManager sharedManager].userName != nil && [ADeanUserDataManager sharedManager].userName.length > 0 && [ADeanUserDataManager sharedManager].userPassword != nil && [ADeanUserDataManager sharedManager].userPassword.length > 0)) { // 用戶名、密碼為空時候強制為未登錄 [ADeanUserDataManager sharedManager].isUserLogined = @NO; } self.window.rootViewController = self.tabbarController; [self.window makeKeyAndVisible]; // 基本頁面跳轉邏輯 /*--------------------------------------*/ if ([[ADeanUserDataManager sharedManager].everLaunched boolValue] == NO) { //是否是第一次啟動判斷 [ADeanUserDataManager sharedManager].everLaunched = [NSNumber numberWithBool:YES]; [self.window addSubview:self.helpViewController.view]; } /*--------------------------------------*/ // 注冊第三方庫 /*--------------------------------------*/ // 注冊Crash統計 -- Crashlytics [Fabric with:@[[Crashlytics class]]]; [MobClick startWithAppkey:UMENG_APPKEY]; [MobClick setCrashReportEnabled:NO]; // 關掉MobClick Crash Report收集開關 #ifdef ADeanForTest [MobClick setCrashReportEnabled:YES]; // 打開MobClick Crash Report收集開關 [MobClick setLogEnabled:YES]; #endif [ShareSDK registerApp:ShareSDKAppKey]; //新浪 [ShareSDK connectSinaWeiboWithAppKey:SinaAppKey appSecret:SinaAppSecret redirectUri:SinaRedirectUri]; //新浪微博客戶端應用 [ShareSDK connectSinaWeiboWithAppKey:SinaAppKey appSecret:SinaAppSecret redirectUri:SinaRedirectUri weiboSDKCls:[WeiboSDK class]]; #if TARGET_IPHONE_SIMULATOR #else //QQ好友 [ShareSDK connectQQWithQZoneAppKey:QZoneAppKey qqApiInterfaceCls:[QQApiInterface class] tencentOAuthCls:[TencentOAuth class]]; #endif //微信朋友圈 [ShareSDK connectWeChatSessionWithAppId:WeiXinAppID wechatCls:[WXApi class]]; //微信好友 [ShareSDK connectWeChatTimelineWithAppId:WeiXinAppID wechatCls:[WXApi class]]; [MiPushSDK registerMiPush:self type:(UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert) connect:YES]; /*--------------------------------------*/ // 其他邏輯 [self registerRemotePushNotification]; [self getSwitchInfoFromService]; [self appIntegrityCheck]; [self appSecurityCheck] ...... return YES; }
下面我們就來看看,有什麼好的辦法可以對AppDelegate進行瘦身,加強代碼的可讀性和可維護性,並將代碼放到適當的地方。
函數模塊化
上述didFinishLaunchingWithOptions中可以按照功能邏輯劃分為:處理啟動邏輯,注冊第三方庫,處理其他邏輯三類。這樣就可以優化為:
// objective-c語言 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { if (!([ADeanUserDataManager sharedManager].userName != nil && [ADeanUserDataManager sharedManager].userName.length > 0 && [ADeanUserDataManager sharedManager].userPassword != nil && [ADeanUserDataManager sharedManager].userPassword.length > 0)) { // 用戶名、密碼為空時候強制為未登錄 [ADeanUserDataManager sharedManager].isUserLogined = @NO; } self.window.rootViewController = self.tabbarController; [self.window makeKeyAndVisible]; // 基本頁面跳轉邏輯 [self baseViewJumpLogic]; // 注冊第三方庫 [self registThirdPart]; // 其他邏輯 [self handleOtherLogic] return YES; } - (void)baseViewJumpLogic { if ([[ADeanUserDataManager sharedManager].everLaunched boolValue] == NO) { //是否是第一次啟動判斷 [ADeanUserDataManager sharedManager].everLaunched = [NSNumber numberWithBool:YES]; [self.window addSubview:self.helpViewController.view]; } } - (void)registThirdPart { // 注冊Crash統計 -- Crashlytics [Fabric with:@[[Crashlytics class]]]; [MobClick startWithAppkey:UMENG_APPKEY]; [MobClick setCrashReportEnabled:NO]; // 關掉MobClick Crash Report收集開關 #ifdef ADeanForTest [MobClick setCrashReportEnabled:YES]; // 打開MobClick Crash Report收集開關 [MobClick setLogEnabled:YES]; #endif [ShareSDK registerApp:ShareSDKAppKey]; //新浪 [ShareSDK connectSinaWeiboWithAppKey:SinaAppKey appSecret:SinaAppSecret redirectUri:SinaRedirectUri]; //新浪微博客戶端應用 [ShareSDK connectSinaWeiboWithAppKey:SinaAppKey appSecret:SinaAppSecret redirectUri:SinaRedirectUri weiboSDKCls:[WeiboSDK class]]; #if TARGET_IPHONE_SIMULATOR #else //QQ好友 [ShareSDK connectQQWithQZoneAppKey:QZoneAppKey qqApiInterfaceCls:[QQApiInterface class] tencentOAuthCls:[TencentOAuth class]]; #endif //微信朋友圈 [ShareSDK connectWeChatSessionWithAppId:WeiXinAppID wechatCls:[WXApi class]]; //微信好友 [ShareSDK connectWeChatTimelineWithAppId:WeiXinAppID wechatCls:[WXApi class]]; [MiPushSDK registerMiPush:self type:(UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert) connect:YES]; } - (void)handleOtherLogic { [self registerRemotePushNotification]; [self getSwitchInfoFromService]; [self appIntegrityCheck]; [self appSecurityCheck] ...... }
模塊化後,代碼瞬間變得易讀很多,而且需要改什麼可以直接去相應的模塊添加。但是這個僅僅是將代碼的順序變化下,相同功能的代碼抽到一個函數中,代碼行數沒有減少,所有的功能還是糅合在一個.m中。
類模塊化
很多其他邏輯是業務邏輯的,可以抽離到業務Model中,通過類模塊化便捷使用。這樣就可以優化為:
// objective-c語言 #import "ADeanAppCheck.h" #import "ADeanSwitches.h" - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { if (!([ADeanUserDataManager sharedManager].userName != nil && [ADeanUserDataManager sharedManager].userName.length > 0 && [ADeanUserDataManager sharedManager].userPassword != nil && [ADeanUserDataManager sharedManager].userPassword.length > 0)) { // 用戶名、密碼為空時候強制為未登錄 [ADeanUserDataManager sharedManager].isUserLogined = @NO; } self.window.rootViewController = self.tabbarController; [self.window makeKeyAndVisible]; // 基本頁面跳轉邏輯 [self baseViewJumpLogic]; // 注冊第三方庫 [self registThirdPart]; // 其他邏輯 [self handleOtherLogic] return YES; } - (void)handleOtherLogic { [ADeanAppCheck appInfoCheck]; // Integrity & Security Check [ADeanSwitches appSwitchInit]; // Get Switch From Service ...... }
分類模塊化
先拋個問題:分類中是否可以定義變量?
如果不知道可以參考:iOS分類中通過runtime添加動態屬性
分類能夠做到的事情主要是:即使在你不知道一個類的源碼情況下,向這個類添加擴展的方法。這裡我們主要是將對外開放的方法和一部分變量拿到分類中處理。這樣進一步輕量化AppDelegate本身進行代碼量。
// objective-c語言 // ADeanAppDelegate+Light.h文件 #import "AppDelegate.h" @interface ADeanAppDelegate (Light) @property (nonatomic, strong) UITabbarController *tabbarController; /*! @brief 全局appDeleaget */ + (AppDelegate *)appDelegate; /*! @method @brief 關閉系統鍵盤 */ + (void)closeKeyWindow; @end // objective-c語言 // ADeanAppDelegate+Light.m文件 #import "ADeanAppDelegate+Light.h" - (UITabbarController *)tabbarController { UITabbarController *tabbarController = objc_getAssociatedObject(self, &kTabbarControllerObjectKey); if (!tabbarController) { tabbarController = [[UITabbarController alloc] init]; objc_setAssociatedObject(self, &kTabbarControllerObjectKey, tabbarController, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } return tabbarController; } - (void)setTabbarController:(UITabbarController *)tabbarController { objc_setAssociatedObject(self, &kTabbarControllerObjectKey, tabbarController, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } + (AppDelegate *)appDelegate { return (AppDelegate *)[[UIApplication sharedApplication] delegate]; } + (void)closeKeyWindow { [[UIApplication sharedApplication].keyWindow endEditing:YES]; } 這樣在AppDelegate中,對外開放的方法和部分變量可以抽離到分類中去。也可以根據作用定義不同的AppDelegate分類: #“ADeanAppDelegate+View.h” #“ADeanAppDelegate+Controller.h” #“ADeanAppDelegate+Method.h” …
這樣代碼結構會更加清晰明了。 抽出來的AppDelegate只剩下注冊第三方庫了,因為第三方庫很多是需要在didFinishLaunchingWithOptions中運行,正常的方法就很難。
Method Swizzling化
Method Swizzling是改變一個selector的實際實現的技術,關於Method Swizzling的概念、原理谷歌一堆。
Method Swizzling中以viewWillAppear為例,講解了Method Swizzling的基本用法。
#import "ADeanAppDelegate+Hook.h" #import "ADeanMethodSwizzling.h" #import "MobClick.h" #import "WXApi.h" #import "WeiboSDK.h" #import #import #import #if TARGET_IPHONE_SIMULATOR #else #import #import #import #endif @implementation ADeanAppDelegate (Hook) + (void)initialize { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ [self adean_AppDelegateHook]; }); } + (void)adean_AppDelegateHook { SwizzlingMethod([ADeanAppDelegate class], @selector(application:didFinishLaunchingWithOptions:), @selector(adean_application:didFinishLaunchingWithOptions:)); SwizzlingMethod([ADeanAppDelegate class], @selector(application:handleOpenURL:), @selector(adean_application:handleOpenURL:)); SwizzlingMethod([ADeanAppDelegate class], @selector(application:openURL:sourceApplication:annotation:), @selector(adean_application:openURL:sourceApplication:annotation:)); SwizzlingMethod([ADeanAppDelegate class], @selector(applicationDidReceiveMemoryWarning:), @selector(adean_applicationDidReceiveMemoryWarning:)); } #pragma mark - Method Swizzling - (BOOL)adean_application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ // 耗時的操作 // 注冊Crash統計 -- Crashlytics [Fabric with:@[[Crashlytics class]]]; // 友盟統計 [MobClick startWithAppkey:UMENG_APPKEY]; [MobClick setCrashReportEnabled:NO]; // 關掉MobClick Crash Report收集開關 #ifdef ADeanForTest [MobClick setCrashReportEnabled:YES]; // 打開MobClick Crash Report收集開關 [MobClick setLogEnabled:YES]; #endif [ShareSDK registerApp:ShareSDKAppKey]; //新浪 [ShareSDK connectSinaWeiboWithAppKey:SinaAppKey appSecret:SinaAppSecret redirectUri:SinaRedirectUri]; //新浪微博客戶端應用 [ShareSDK connectSinaWeiboWithAppKey:SinaAppKey appSecret:SinaAppSecret redirectUri:SinaRedirectUri weiboSDKCls:[WeiboSDK class]]; #if TARGET_IPHONE_SIMULATOR #else //QQ好友 [ShareSDK connectQQWithQZoneAppKey:QZoneAppKey qqApiInterfaceCls:[QQApiInterface class] tencentOAuthCls:[TencentOAuth class]]; #endif //微信朋友圈 [ShareSDK connectWeChatSessionWithAppId:WeiXinAppID wechatCls:[WXApi class]]; //微信好友 [ShareSDK connectWeChatTimelineWithAppId:WeiXinAppID wechatCls:[WXApi class]]; }); return [self adean_application:application didFinishLaunchingWithOptions:launchOptions]; } - (BOOL)adean_application:(UIApplication *)application handleOpenURL:(NSURL *)url { [ShareSDK handleOpenURL:url wxDelegate:self]; return [self adean_application:application handleOpenURL:url]; } - (BOOL)adean_application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation { [ShareSDK handleOpenURL:url sourceApplication:sourceApplication annotation:annotation wxDelegate:self]; return [self adean_application:application openURL:url sourceApplication:sourceApplication annotation:annotation]; } - (void)adean_applicationDidReceiveMemoryWarning:(UIApplication *)application { [self adean_applicationDidReceiveMemoryWarning:application]; } @end
這下再去看下AppDelegate文件,代碼不超過200行了。
小結
Method Swizzling常見的應用場景:
1.用於記錄或者存儲,比方說記錄ViewController進入次數、Btn的點擊事件、ViewController的停留時間等等。 可以通過Runtime獲取到具體ViewController、Btn信息,然後傳給服務器。
2.添加需要而系統沒提供的方法,比方說修改Statusbar顏色。
3.用於輕量化、模塊化處理,如上面介紹的,代碼輕量化處理。
Method Swizzling是把雙刃劍,需要正確理解它的使用。
分類增加變量的使用場景:
1.過多繼承時,可以通過分類減少繼承層級,清晰流程框架。比方說,ViewController可能需要相互沖突的事件,單一父類會導致邏輯復雜。這時候可以通過分類簡化邏輯,不同的ViewController引用不同的分類。
2.擴展類屬性。
上面我們學習了一些瘦身的技巧,希望通過這些方法寫出更可讀性更高,可維護性更高的代碼。
提醒:
本文涉及到的Demo已經放到GitHub上了。Demo可能與本文有點出入,部分函數命名跟文章中不一致。