如此SO答案中所述，我们必须发送另一个推送通知以清除以前发送的通知.

As mentioned in this SO answer we have to send another push notification to clear previously sent notifications.

该通知应包含badge:0，并省略alert和sound字段，然后它将从通知中心删除通知，并清除应用程序徽章.

That notification should contain badge:0, and omit the alert and sound fields, then it will remove notifications from notification centre as well as clear app badge.