Using IntentService instead of AsyncTask for Broadcast Receiver?

问题

I am in the process of trying to get an email sent using BroadcastReceiver, the code is working correct using AsyncTask when using onClick but does not work when AlarmReceiver is being called.

Would it be better to use IntentService for this method? If so, what is the best way to write this?

Can anyone help with this problem? I am still new to java and want to help improve my knowledge. :)

Any help would be appreciated! Thank you!

AlarmReceiver.java

import android.app.Activity;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.support.v4.app.NotificationCompat;
import android.content.BroadcastReceiver;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Toast;
import static android.graphics.Color.GREEN;

public class AlarmReceiver extends BroadcastReceiver {

Context cxt;
Activity context;

@Override
public void onReceive(Context arg0, Intent arg1) {

    cxt = arg0;

    addNotification();
    new SendMail().execute();
}


private class SendMail extends AsyncTask<String, Integer, Void> {

    protected Void doInBackground(String... params) {
        Mail m = new Mail("youremail@gmail.com", "password");

        String[] toArr = {"toemail@outlook.com"};
        m.setTo(toArr);
        m.setFrom("fromemail@gmail.com");
        m.setSubject("Achieve Alert!");
        m.setBody("This is a reminder about your upcoming assignment or examination!");

        try {
            if(m.send()) {
                Toast.makeText(context.getApplicationContext(), "Email was sent successfully.", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(context.getApplicationContext(), "Email was not sent.", Toast.LENGTH_LONG).show();
            }
        } catch(Exception e) {
            Log.e("MailApp", "Could not send email", e);
        }
        return null;
    }
}
}

回答1:

First start Intent service from Alarm manager :

 private void setAlarm(Calendar targetCal){

   /* HERE */     Intent intent = new Intent(getBaseContext(), AlarmService.class);
        final int _id = (int) System.currentTimeMillis();

      /* HERE */  PendingIntent pendingIntent = PendingIntent.getService(this,_id,intent,PendingIntent.FLAG_ONE_SHOT);

        AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
    ......
    .....

Now Intent Service class:

 public class AlarmService extends IntentService {

PowerManager powerManager;
    PowerManager.WakeLock wakeLock;

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

    @Override
    protected void onHandleIntent(Intent intent) {
        powerManager = (PowerManager) getSystemService(POWER_SERVICE);
        wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "FCFCFCFC");

        wakeLock.acquire();

       addNotification();
       sendMAIL();

    }


    public void addNotification() {
    NotificationCompat.Builder builder =
            new NotificationCompat.Builder(getApplicationContext())
                    .setSmallIcon(R.drawable.icon_transperent)
                    .setLights(GREEN, 700, 700)
                    .setContentTitle("Achieve - Alert!")
                    .setContentText("This is a reminder for your deadline!");

    Intent notificationIntent = new Intent(getApplicationContext(), MainMenu.class);
    PendingIntent contentIntent = PendingIntent.getActivity(getApplicationContext(), 0,     notificationIntent,
            PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(contentIntent);

    // Add as notification
    NotificationManager manager = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    builder.setVibrate(new long[] { 0, 1000, 1000, 1000, 1000 });
    manager.notify(0, builder.build());
}

    public void sendMAIL(){

    Mail m = new Mail("youremail@gmail.com", "password");

        String[] toArr = {"toemail@outlook.com"};
        m.setTo(toArr);
        m.setFrom("fromemail@gmail.com");
        m.setSubject("Achieve Alert!");
        m.setBody("This is a reminder about your upcoming assignment or examination!");

        try {
            if(m.send()) {
                Toast.makeText(getApplicationContext(), "Email was sent successfully.", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(getApplicationContext(), "Email was not sent.", Toast.LENGTH_LONG).show();
            }
        } catch(Exception e) {
            Log.e("MailApp", "Could not send email", e);
        }


        wakeLock.release();

    }


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

Now, Manifest add:

<uses-permission android:name="com.android.alarm.permission.SET_ALARM"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>

<service android:name=".AlarmService" android:exported="true" android:enabled="true"/>

来源：https://stackoverflow.com/questions/42859196/using-intentservice-instead-of-asynctask-for-broadcast-receiver