Android:警报在预定时间之前被触发

Question

我试图在应用程序启动 10 分钟后生成警报。根据我的要求，无论用户关闭应用程序、关闭并再次打开，还是重启后，这个警报都应该起作用。下面是我的代码。

MainActivity.java

import android.app.ActivityManager;
import android.app.Application;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private Context context;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        this.context=this;

        startService(new Intent(getBaseContext(), MyService.class));

    }

    public void startService(View view) {
      //  startService(new Intent(getBaseContext(), MyService.class));
    }

    // Method to stop the service
    public void stopService(View view) {
      //  stopService(new Intent(getBaseContext(), MyService.class));
    }

}

MyService.java - 这是服务类。

import android.app.AlarmManager;
import android.app.IntentService;
import android.app.PendingIntent;
import android.app.Service;
import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.IBinder;
import android.os.SystemClock;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Calendar;
import java.util.GregorianCalendar;

/**
 * Created by Nirodha Mihiran on 6/8/2016.
 */
public class MyService extends Service {

    public static boolean doneCreted = false;

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }


    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // Let it continue running until it is stopped.

        Toast.makeText(this, "Service Started Second", Toast.LENGTH_LONG).show();

        Calendar calendar = new GregorianCalendar();
        calendar.setTimeInMillis(System.currentTimeMillis() + 10 * 60 * 1000);

        intent = new Intent(MyService.this, AlarmReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(MyService.this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
        AlarmManager am = (AlarmManager) MyService.this.getSystemService(MyService.this.ALARM_SERVICE);
        // am.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 1000 * 60 * 5, pendingIntent);
        // am.setWindow(AlarmManager.RTC_WAKEUP,calendar.getTimeInMillis(), 1000 * 60 * 5 , pendingIntent);
        am.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);

        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Toast.makeText(this, "Service Destroyed", Toast.LENGTH_LONG).show();
    }

}

AlarmReciever.java

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Calendar;
import java.util.GregorianCalendar;

/**
 * Created by thisararanawaka on 6/2/16.
 */
public class AlarmReceiver extends BroadcastReceiver {
    private int MID = 0;

    public static boolean isCreated;

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub

        long when = System.currentTimeMillis();

        Calendar calendar = new GregorianCalendar();
        calendar.setTimeInMillis(System.currentTimeMillis()+5*60*1000);

        NotificationManager notificationManager = (NotificationManager) context
                .getSystemService(Context.NOTIFICATION_SERVICE);

        Intent notificationIntent = new Intent(context, MainActivity.class);
        notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0,
                notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);

        Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

        NotificationCompat.Builder mNotifyBuilder = new NotificationCompat.Builder(
                context).setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle("Alaram Fired")
                .setContentText("Events To be Performed").setSound(alarmSound)
                .setAutoCancel(true)
                .setContentIntent(pendingIntent)

                .setVibrate(new long[]{1000, 1000, 1000, 1000, 1000});
        notificationManager.notify(MID, mNotifyBuilder.build());
        MID++;

        Toast.makeText(context, "Notification Created .", Toast.LENGTH_LONG).show();
    }
}

如果我没有关闭并关闭手机或重新启动手机，我可以按时收到警报。我按时接到闹钟。

但是，如果我关闭并打开手机，或者如果我重新启动手机，我会在手机打开/重启后立即收到警报和通知 - 可能在一分钟后。在这种情况下，即使闹钟安排在明天也没关系，我会在手机开机/重启后立即收到。

我做错了什么？

Answer 1

通过查看您的代码，这可能是一个原因

在您的 onStartCommand() 中，您将时间设置为 calendar.setTimeInMillis(System.currentTimeMillis() + 10 * 60 * 1000);

设置日历时间 + 10 分钟，然后您在下面的行中设置相同的时间 am.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);

这样试试，

long myAlarmTime = System.currentTimeMillis() + 10 * 60 * 1000; am.set(AlarmManager.RTC_WAKEUP, myAlarmTime, pendingIntent);

重启后出现这个问题的原因

服务可以被系统运行的原因有两个。如果有人调用 Context.startService() 那么系统将检索服务(创建它并在需要时调用它的 onCreate() 方法)然后使用客户端提供的参数调用它的 onStartCommand(Intent, int, int) 方法。此时服务将继续运行，直到调用 Context.stopService() 或 stopSelf()。 https://developer.android.com/reference/android/app/Service.html