1.推送权限

对于远程推送而言，我们可以直接调用[application registerForRemoteNotifications];来获取deviceToken，传给后台。并不需要用户在“通知权限弹框中”允许。

“通知权限弹框”真正询问的是 是否允许 推送有弹框、声音、角标。

2.注册推送

依赖头文件<UserNotifications/UserNotifications.h>

    if ([[UIDevice currentDevice].systemVersion floatValue] >= 10.0) {
        UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
        // UNUserNotificationCenterDelegate 
        center.delegate = self;
        [center requestAuthorizationWithOptions:(UNAuthorizationOptionAlert | UNAuthorizationOptionBadge | UNAuthorizationOptionSound) completionHandler:^(BOOL granted, NSError * _Nullable error) {
            if (granted) {
                // 点击允许
                NSLog(@"注册成功");
                [center getNotificationSettingsWithCompletionHandler:^(UNNotificationSettings * _Nonnull settings) {
                    NSLog(@"%@", settings);
                }];
            } else {
                // 点击不允许
                NSLog(@"注册失败");
            }
        }];
    }else if ([[UIDevice currentDevice].systemVersion floatValue] >8.0){
        //iOS8 - iOS10
        [application registerUserNotificationSettings:[UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeAlert | UIUserNotificationTypeSound | UIUserNotificationTypeBadge categories:nil]];
        
    }else if ([[UIDevice currentDevice].systemVersion floatValue] < 8.0) {
        //iOS8系统以下
        [application registerForRemoteNotificationTypes:UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeSound];
    }
    // 注册 获取device Token
    [[UIApplication sharedApplication] registerForRemoteNotifications];

3.远程推送回调代理方法

*iOS10以前

1. UIApplication中有两个关于推送通知的代理回调：

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo NS_DEPRECATED_IOS(3_0, 10_0, ");

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler NS_AVAILABLE_IOS(7_0);

2. 二者的区别：调用时机不同

didReceiveRemoteNotification 只会在APP 处于运行中（前台、后台）时，会调用。
didReceiveRemoteNotification fetchCompletionHandler 会在APP处于运行中 或者被杀死状态都会被调用。

3. 注意

当你两个方法都实现了 ，系统只会调用didReceiveRemoteNotification fetchCompletionHandler

*iOS 10以后

1.UIApplication中多了UNUserNotificationCenterDelegate的三个代理回调方法

(1)app在前台收到通知

- (void)userNotificationCenter:(UNUserNotificationCenter *)center willPresentNotification:(UNNotification *)notification withCompletionHandler:(void (^)(UNNotificationPresentationOptions options))completionHandler __IOS_AVAILABLE(10.0) __TVOS_AVAILABLE(10.0) __WATCHOS_AVAILABLE(3.0) __OSX_AVAILABLE(10.14);

(2)点击通知栏

- (void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void(^)(void))completionHandler __IOS_AVAILABLE(10.0) __WATCHOS_AVAILABLE(3.0) __OSX_AVAILABLE(10.14) __TVOS_PROHIBITED;

(3)打开通知设置

- (void)userNotificationCenter:(UNUserNotificationCenter *)center openSettingsForNotification:(nullable UNNotification *)notification __IOS_AVAILABLE(12.0) __OSX_AVAILABLE(10.14) __WATCHOS_PROHIBITED __TVOS_PROHIBITED;

4. 发送推送格式

（1）普通推送

{"aps":{"alert":"测试推送","badge":3,"sound": "default"},"json":"自定义结构"}

（2）静默推送

{"aps":{"content-available": 1},"json":"自定义结构"}

5.Capabilities 设置

推送开关.png Capabilities设置.png