flutter - 如何在Flutter中暂停或停止Android Alarm Manager的回调功能？

Question

我正在开发一个应用程序，每次用户锁定手机时，我都必须暂停或停止Android Alarm Manager的回调功能。我也不知道如何检测用户是否锁定了手机。

我尝试使用应用程序生命周期管理，但是当用户同时锁定和最小化应用程序时的结果是相同的。下面是代码。请看一下:

import 'package:flutter/material.dart';
import 'package:flutter_datetime_picker/flutter_datetime_picker.dart';
import 'package:intl/intl.dart';

import 'CommonPicker.dart';
import 'fileUtils.dart';
import 'package:android_alarm_manager/android_alarm_manager.dart';


void callback(){
  print("I am in the isolate");
  DateTime now=DateTime.now().toLocal();
 print("Date time:");
 print(now);
 //operation to be performed
  print("last line of Isolate");
}

class AlertTime2 extends StatefulWidget {
  static const routeName = '/alertTime2';

  @override
  _AlertTime2State createState() => _AlertTime2State();
}

class _AlertTime2State extends State<AlertTime2> {
  String mm = "00";
  String ss = "00";
  var mmValue;
  var ssValue;
  var totalTimeInSec;
  String _selectedTime;

  @override
  void initState() {
    super.initState();

    FileUtils().readFromFile().then((String value) {
      setState(() {
        _selectedTime = value;
      });
    });
  }


  void alarm_managing_function(int t) async {
    await AndroidAlarmManager.initialize();
    await AndroidAlarmManager.periodic(Duration(seconds: t), 0, callback);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Column(
      children: <Widget>[
        Padding(
          padding: const EdgeInsets.fromLTRB(30, 70, 0, 0),
          child: Text(
            "Timer for Notification",
            style: TextStyle(
              fontSize: 50,
            ),
          ),
        ),
        Padding(
          padding: const EdgeInsets.fromLTRB(0, 150, 0, 0),
          child: Text(
            "MM-SS",
            style: TextStyle(
              fontSize: 30,
              fontWeight: FontWeight.bold,
            ),
          ),
        ),
        Padding(
          padding: const EdgeInsets.fromLTRB(0, 0, 0, 0),
          child: Text(
            "${_selectedTime ?? 'Selected Time'}",
            style: TextStyle(fontWeight: FontWeight.bold, fontSize: 38),
          ),
        ),
        RaisedButton(
          onPressed: () {
            DatePicker.showPicker(context,
                showTitleActions: true,
                pickerModel:
                    CustomPicker(currentTime: DateTime.tryParse(_selectedTime)),
                onConfirm: (time) {
              setState(() {
                print(time);
                _selectedTime = DateFormat("mm-ss").format(time);
                FileUtils().saveToFile(_selectedTime);

                mm = _selectedTime.substring(0, 2);
                ss = _selectedTime.substring(3, 5);
                print(mm);
                print(ss);
                mmValue = int.parse(mm);
                ssValue = int.parse(ss);
                totalTimeInSec = mmValue * 60 + ssValue;
                print(totalTimeInSec);
                DateTime now=DateTime.now().toLocal();
                alarm_managing_function(totalTimeInSec);
              });
            }, locale: LocaleType.en);
          },
          child: Text("Show Time picker"),
        ),

        ),
      ],
    ));
  }
}

Answer 1

您已插入此代码行以停止或暂停警报

cancel = await AndroidAlarmManager.cancel(id);

传递您要停止的警报的ID。