这也有效，到达时不播放声音:

This works also and does not play a sound when it arrives:

{
    aps = {
        "content-available" : 1,
        sound : ""
    };
}

编辑

遇到此问题的人可能想查看此链接.我一直在参与 Apple 开发者论坛上的一个帖子，该帖子讨论了所有应用程序状态以及何时接收和未接收到静默推送.

People having this problem may want to check out this link. I have been participating in a thread on Apple's Developer forum that goes over all app states and when silent pushes are received and not received.