我想在用户预先设置的时间使用 AlarmManager 实现从服务器向用户发送通知。代码如下:

主要 Activity :

public void set_Retrival_then_notifcation_Alarm(Context context, int year, int month, int day, int hour, int min, int sec) 
    {
        Calendar updateTime = Calendar.getInstance();
        updateTime.setTimeZone(TimeZone.getDefault());
        updateTime.set(Calendar.YEAR, year);
        updateTime.set(Calendar.MONTH, month-1);
        updateTime.set(Calendar.DATE, day);
        updateTime.set(Calendar.HOUR_OF_DAY, hour);
        updateTime.set(Calendar.MINUTE, min);
        updateTime.set(Calendar.SECOND, sec);
        Intent downloader = new Intent(context, AlarmBroadcastReceiver.class);
        downloader.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, downloader, PendingIntent.FLAG_CANCEL_CURRENT);
        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);           
        alarmManager.set(AlarmManager.RTC_WAKEUP, updateTime.getTimeInMillis(), pendingIntent);                        
    }

解析服务:

public class ParseService extends IntentService 
{
    static String Parse_AppID = "abc";  
    static String Parse_ClientKey = "abckey";
    String notification_next_price = "";
    String notification_next_date = "";
    SharedPreferences settings;

    public class LocalBinder extends Binder 
    {
        public ParseService getService() 
        {
            return ParseService.this;
        }
    }

    public ParseService() 
    {
        super("ParseService");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        super.onStartCommand(intent,flags,startId);
        return START_STICKY ;
    }

    @Override
    protected void onHandleIntent(Intent intent) 
    {
        Log.d("MyService", "About to execute MyTask");
        new MyTask().execute();
    }

    private class MyTask extends AsyncTask<String, Void, Boolean> 
    {
        @Override
        protected Boolean doInBackground(String... strings) 
        {
            Log.d("MyService - MyTask", "Calling doInBackground within MyTask");
            initParse(ParseService.this);
            get_notification_info(ParseService.this);
            return false;
        }
    }

    private void sendNotification(Context context, String title, String content) 
    {
        Log.d("MyService - MyTask", "A - sendNotification");
        settings = context.getSharedPreferences("MyApp",0);
        boolean notify_is_on = settings.getBoolean("notify_is_on", true);
        int saved_amount = settings.getInt("saved_amount", 800);

        NumberFormat numberFormat = NumberFormat.getInstance();
        int k = 0;
        try
        {
            k = numberFormat.parse(notification_next_price).intValue();
            if (notify_is_on && (k >= (saved_amount*10000)))
            {
                setNotificationContent(context, k, ""+title, content + "");
            }
            else
            {
                Toast.makeText(getApplicationContext(), "No need notification", Toast.LENGTH_SHORT).show();
            }
        }
        catch (Exception ex)
        {
            setNotificationContent(context, k, "Title2", "Content2");
        }
    } 

    public void setNotificationContent(Context context, int k, String title, String content)
    {
        Intent notificationIntent = new Intent(context, CurrentResult.class);
        PendingIntent pi = PendingIntent.getActivity(context, 0, notificationIntent, 0);
        Notification noti = new Notification.Builder(context)
            .setTicker("Hello")
            .setSmallIcon(R.drawable.b06)
            .setLargeIcon(BitmapFactory.decodeResource(context.getResources(), R.drawable.ic_launcher))
            .setAutoCancel(true)
            .setOngoing(true) 
            .setOnlyAlertOnce(true)
            .setContentTitle(""+title)
            .setContentText(""+content)
            .setContentIntent(pi)
         .build();

        startForeground(1337, noti);

        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(0, noti);

        stopSelf();
    }

    @Override
    public void onCreate() {
        super.onCreate();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public boolean onUnbind(Intent intent) {
        return super.onUnbind(intent);
    }

    public void initParse(Context context) 
    {
        try 
        {
            ...connection to Parse.com
        } 
        catch (Exception e) 
        {
            e.printStackTrace();
        }
    }

    public void get_notification_info(Context context)
    {       
        ParseQuery<ParseObject> query = ParseQuery.getQuery("Record_db");
        //....getting records from server
        sendNotification(ParseService.this, ""+notification_next_price, ""+notification_next_date);
                    }                   
                } 
                else 
                {
                    Toast.makeText(getApplicationContext(), "Getting server content error", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

报警广播管理器

public class AlarmBroadcastReceiver extends BroadcastReceiver 
{
    public AlarmBroadcastReceiver () {
    }

    @Override
     public void onReceive(Context context, Intent intent) 
     {
         Intent dailyUpdater = new Intent(context, ParseService.class); 
         context.startService(dailyUpdater);
         Log.d("AlarmReceiver", "Called context.startService from AlarmReceiver.onReceive");
     }
}

list :

<service android:name="com.abc.abc.ParseService" 
                android:enabled="true"
                android:exported="true" />
        <receiver 
            android:name="com.abc.abc.AlarmBroadcastReceiver"
            android:enabled="true"
            android:exported="true" >
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </receiver>         

问题:

当应用程序在最近的任务列表中时，从服务器获取记录并发送到通知可以正常工作。

但是，如果应用程序被手动从最近的任务列表中删除，则 alarmManager 和通知将被取消，因此不会收到任何通知。

我用谷歌搜索了一下，大多数解决方案是在 onStartCommand 中返回 START_STICKY，在 Manifest 中注册，但我试过没有成功。

能帮忙看看是什么问题吗？为什么手动将应用从最近任务列表中移除后，通知无法重启？是否有任何例子表明此 ParseService 在用户预设的时间工作？

谢谢!

最佳答案

• 您需要将注册的警报存储在本地数据库中
• 然后创建一个启动时完成的接收器
  • 在此接收器中加载所有警报并再次注册
• 在 AlarmBroadcastReceiver 类中从数据库中删除此警报

就是这样

关于Android AlarmManager 在重启后继续/从 RecentTaskManager 中删除，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40615514/