2019独角兽企业重金招聘Python工程师标准>>> 
清除通知栏所有通知
//只要设置角标不相同时，再设置为0就可以清除
[UIApplication sharedApplication].applicationIconBadgeNumber = 1;
[UIApplication sharedApplication].applicationIconBadgeNumber = 0;
推送通知进入后台处理通知消息
1.后台推送消息设置，要再推送消息中加入键值对__"content-available" = 1__。这种方式为静默推送 例如：
aps = {
alert = "一条新的消息";
"content-available" = 1;
sound = default;
};
2.App端的需要远程通知后台模式，在plist添加如下key
<key>UIBackgroundModes</key>
<array>
<string>fetch</string>
<string>remote-notification</string>
</array>
消息处理在如下方法回调中
- (void)application:(UIApplication *)application
didReceiveRemoteNotification:(NSDictionary *)userInfo
fetchCompletionHandler:
(void (^)(UIBackgroundFetchResult))completionHandler {
NSLog(@"收到推送通知:%@", userInfo);
completionHandler(UIBackgroundFetchResultNewData);
}