iOS推送（一）：本地推送

以iOS8.0和iOS10.0两个版本来创建一个本地推送：

- (void)localPush{// iOS8.0下本地推送的创建方式    if ([UIDevice currentDevice].systemVersion.floatValue < 10.0) {        UILocalNotification *localNotification = [[UILocalNotification alloc] init];        localNotification.fireDate = [NSDate dateWithTimeIntervalSinceNow:5.0];        localNotification.alertBody = @"这是一条本地推送，这是推送主体！";        localNotification.soundName = UILocalNotificationDefaultSoundName;        localNotification.applicationIconBadgeNumber += 1;        [[UIApplication sharedApplication] scheduleLocalNotification:localNotification];      // iOS10.0      }else {        // 给推送一个标识符        NSString *identifier = @"localPush.identifier";        // 推送内容        UNMutableNotificationContent *content = [UNMutableNotificationContent new];        content.body = @"这是iOS10的本地推送，这是推送主体！";        content.badge = @1;     // 推送触发器   //        UNTimeIntervalNotificationTrigger *trigger = [UNTimeIntervalNotificationTrigger triggerWithTimeInterval:60 repeats:YES];        NSDateComponents *components = [NSDateComponents new];        components.second = 5.0f;        UNCalendarNotificationTrigger *trigger = [UNCalendarNotificationTrigger triggerWithDateMatchingComponents:components repeats:YES];        // 推送请求        UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier:identifier content:content trigger:trigger];        // 把推送请求添加到推送中心        [[UNUserNotificationCenter currentNotificationCenter] addNotificationRequest:request withCompletionHandler:^(NSError * _Nullable error) {            NSLog(@"%@", [error localizedDescription]);        }];    }}

推送创建完毕后，那么我们便要考虑收到推送后会执行什么样的操作，这里主要介绍处理接收到推送的地方。

首先我们要先注册推送通知。8.0和10.0注册推送还是很不一样的。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    // 8.0系统注册推送    if ([[UIDevice currentDevice].systemVersion floatValue] < 10.0) {        UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge|UIUserNotificationTypeAlert|UIUserNotificationTypeSound categories:nil];        [application registerUserNotificationSettings:settings];    // iOS10.0注册推送      }else{        [UNUserNotificationCenter currentNotificationCenter].delegate = self;        [[UNUserNotificationCenter currentNotificationCenter] requestAuthorizationWithOptions:UNAuthorizationOptionBadge|UNAuthorizationOptionSound|UNAuthorizationOptionAlert completionHandler:^(BOOL granted, NSError * _Nullable error) {            if (error != nil) {                NSLog(@"%@", [error localizedDescription]);            }        }];        [[UNUserNotificationCenter currentNotificationCenter] getNotificationSettingsWithCompletionHandler:^(UNNotificationSettings * _Nonnull settings) {            NSLog(@"%@", settings);        }];    }// 如果是点击推送进入的App，那么lauchOptions会有一个UIApplicationLaunchOptionsLocalNotificationKey字段，如果这个字段不为空，代表是点击推送进入，并且可以获得推送的内容。注意这个key在iOS10以后也有值，不要和userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:这个方法重复了。所以要判断一下版本是否小于10.0。    if (([[UIDevice currentDevice].systemVersion floatValue] < 10.0) && launchOptions[UIApplicationLaunchOptionsLocalNotificationKey]) {      // ......在点击推送进入App后会执行的代码。  }    return YES;}

iOS10以后，如果程序被销毁后（即程序退出后），收到推送，点击推送进入app，会调用该方法；在该方法里可以执行需要执行的代码，注意两点：
一.要调用一下completionHandler()；
二.要在

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 

中设置一下代理：

[UNUserNotificationCenter currentNotificationCenter].delegate = self
;
否则该代理方法不会执行。

- (void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void (^)())completionHandler{    //......程序退出时收到推送执行的操作    completionHandler();}

iOS8.0以后，如果程序在前台，收到推送会调用该方法：

- (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification{    //......程序在前台时收到推送执行的操作}

iOS10.0以后，如果程序在前台，收到推送会调用该方法：

- (void)userNotificationCenter:(UNUserNotificationCenter *)center willPresentNotification:(UNNotification *)notification withCompletionHandler:(void (^)(UNNotificationPresentationOptions))completionHandler{    //......程序在前台时收到推送执行的操作    completionHandler(UNNotificationPresentationOptionSound | UNNotificationPresentationOptionBadge | UNNotificationPresentationOptionAlert);}