之前用：
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
//reset badge number
//application.applicationIconBadgeNumber = 0
//for debug
application.applicationIconBadgeNumber = 20
结果无效：
会去看app图标，还是没有红色的20数字显示：
换成：
UIApplication.sharedApplication().applicationIconBadgeNumber = 20
也没用。
但是调试期间，注意到，上次到调试时用：
application.applicationIconBadgeNumber = 20
设置的20，第二次启动app时数值有效果的：
2016-04-26 10:09:17.017 [Debug] [main] [AppDelegate.swift:54] application(_:didFinishLaunchingWithOptions:) > didFinishLaunchingWithOptions launchOptions=nil
(lldb) po application.applicationIconBadgeNumber
20
(lldb) po UIApplication.sharedApplication().applicationIconBadgeNumber
20
(lldb) po application.applicationIconBadgeNumber
20
(lldb) po UIApplication.sharedApplication().applicationIconBadgeNumber
20
ios applicationIconBadgeNumber not work
ios – Push notification applicationIconBadgeNumber is not update in ios7 – Stack Overflow
ios8 – How to correctly set application badge value in iOS 8? – Stack Overflow
->好像是想要支持本地通知？才可以设置程序app图标数字？
模拟器上面有问题，真机就生效了？
applicationIconBadgeNumber is not updated | Apple Support Communities
applicationIconBadgeNumber not work
UILocalNotification Class Reference
－》applicationIconBadgeNumber – UIApplication Class Reference
applicationiconbadgenumber not working
How to reset/clear the iOS App’s badge? – Unity Answers
applicationiconbadgenumber 不显示
applicationIconBadgeNumber不显示 – fangdong65的专栏 – 博客频道 – CSDN.NET
－》好像都表示：
必须注册本地通知（或远程通知）中的允许更新badage，然后才能通过applicationIconBadgeNumber去更新app图标数字？
但是官网的api中没有这个提示啊。。。
ios推送消息的applicationIconBadgeNumber问题，在线等-敏捷大拇指-全球最大的Swift开发者社区 苹果粉丝家园 智能移动门户
有延时？？？
我是也是：applicationIconBadgeNumber有值，但是app图标不显示
后来去试了试，果然是：
必须先注册，此处的，本地通知，允许设置对应的badge值，然后才起效果
对应的，第一次运行app时，需要提示用户要求通知权限：
之后，即可通过代码：
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
//enable notification
let notifSettings = UIUserNotificationSettings(forTypes: [UIUserNotificationType.Alert, UIUserNotificationType.Badge, UIUserNotificationType.Sound], categories: nil)
application.registerUserNotificationSettings(notifSettings)
//fixbug to make iPhone local notification work
application.beginBackgroundTaskWithName("showNotification", expirationHandler: nil)
//for debug
application.applicationIconBadgeNumber = 20
去设置app图标数字为20了：
［总结］
之前，虽然已经注册了远程通知，但是没有注册本地通知，所以设置app图标徽章数字badge值：
application.applicationIconBadgeNumber = 0
application.applicationIconBadgeNumber = 20
不起效果。
后来去注册了本地通知，其中支持badge，然后上述代码就起效果了。
代码为：
//enable notification -> othewise later set badge number will not work
let notifSettings = UIUserNotificationSettings(forTypes: [UIUserNotificationType.Alert, UIUserNotificationType.Badge, UIUserNotificationType.Sound], categories: nil)
application.registerUserNotificationSettings(notifSettings)
//fixbug to make iPhone local notification work
application.beginBackgroundTaskWithName("showNotification", expirationHandler: nil)
UIApplication.sharedApplication().applicationIconBadgeNumber = 0
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