我在Flutter背景提取工作，但它给了我一些错误的无头任务。
原因：java.lang.NullPointerException：尝试对空对象引用调用虚拟方法“android.app. Applicationandroid.app.Activity.getApplication（）”
Application.java package com.xxxx.xxxxapp;

import com.transistorsoft.flutter.backgroundfetch.BackgroundFetchPlugin;

import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugins.GeneratedPluginRegistrant;

public class Application extends FlutterApplication implements PluginRegistry.PluginRegistrantCallback {
  @Override
  public void onCreate() {
    super.onCreate();
    BackgroundFetchPlugin.setPluginRegistrant(this);
  }

  @Override
  public void registerWith(PluginRegistry registry) {
    GeneratedPluginRegistrant.registerWith(registry);
  }
}