iOS 被删后台后不能触发 jpush.backgroundNotification 的监听事件

WARNING: 如果不按照这个表格，我们将无法帮助你，并将忽略你的问题。

你的运行环境

• 插件版本:
• 平台（Android / iOS）: iOS
• Cordova version (cordova -v): 8.1.2 (cordova-lib@8.1.1)
• Cordova platform version (cordova platform ls): ios 4.5.5
• Ionic Version (if using Ionic): CLI 4.12.0

期望效果

1. 手机按home进入后台，可以监听 jpush.backgroundNotification 事件并触发回掉.
2. 手机双击home键把app在后台删掉（或iOS为了优化内存自动删掉后台）后，依然可以监听 jpush.backgroundNotification 事件并触发回掉.

实际效果

1. 手机按home进入后台后，一段时间内还能监听 jpush.backgroundNotification 事件，但过了一段时间（约15分钟）后，即使app还在后台，已经不能监听 jpush.backgroundNotification 事件了
2. 手机双击home键并删除app后台后，jpush.backgroundNotification 立即不能被触发。

重现步骤

1. 在 home.ts（主页面）中监听 jpush 事件

import {JPush} from "@jiguang-ionic/jpush";
import {TextToSpeech} from "@ionic-native/text-to-speech";

constructor(
  public jpush: JPush,
  private tts: TextToSpeech,
) {

  document.addEventListener(
    "jpush.receiveNotification",
    (event: any) => {
      this.jpushNotification(event, true)
    },
    false
  );

  document.addEventListener(
    "jpush.backgroundNotification", 
    (event: any) => {
      this.jpushNotification(event, false)
    },
  false
  );
}

jpushNotification(event, showAlert){
  var content;
  if (this.device.platform == "Android") {
    content = event.alert;
  } else {
    content = event.aps.alert;
  }
  if (showAlert) {
    alert("Receive notification: " + JSON.stringify(event));
  }
  this.speak(event.extras.content);
}

speak(content){
  this.tts.speak({text:mytext,locale:"zh-HK",rate:1.4})
    .then(() => console.log('Success'))
    .catch((reason: any) => console.log(reason));
}

2. 进入极光开发者后台创建推送，并点选了 content-available 选项
3. app 在前台或刚进入后台都能正常触发监听事件并播报声音
4. app 进入后台一段时间后，或被删后台，能接收推送但监听事件没被触发

背景

你尝试做过些什么？

Debug logs

包括 Android 或 iOS 的日志：

• iOS: XCode logs
  • Android: $ adb logcat / Android Studio logcat

Start by reproducing the behavior with the listed Cordova, iOS platform, Ionic, and JPush versions using the listener setup in home.ts. Compare foreground, background, and removed-from-background states, and collect the requested Xcode logs. Done means the plugin's behavior for each state is established and the issue is either fixed with a verified callback or clearly documented as an iOS limitation.