sendWakefulWork not always called with cwac-wakeful-1.1.0

Question

I've got a problem for a long time now and I discovered cwac-wakeful, which could solve all my problems. I thought... :'( In short, for solving the problem, I've implemented a most simple app, which schedules alarm every 60 seconds and logs everytime. Here's my code :

MainActivity :

package com.par.hasard.mysimpleapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button = (Button)findViewById(R.id.myExportButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                MyLogManager.copyLogToClipboard(view.getContext());
                MyLogManager.emptyLogFile(view.getContext());
            }
        });
        try {
            MyLogManager.createLogFile(this);
            MyLogManager.write(this, "Application launched\n");
            MyAlarmPlanner.planAlarm_v2(this);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

MyAlarmPlanner :

package com.par.hasard.mysimpleapplication;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.SystemClock;
import android.widget.Toast;
import com.commonsware.cwac.wakeful.WakefulIntentService;
import java.io.IOException;

public class MyAlarmPlanner {
    public static void planAlarm_v2(Context context) throws IOException {
        MyLogManager.write(context, "Beginning of planAlarm_v2\n");
        WakefulIntentService.scheduleAlarms(new MyAppListener(), context, true);
        MyLogManager.write(context, "End of planAlarm_v2\n");
    }
}

MyAppListener :

package com.par.hasard.mysimpleapplication;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.os.SystemClock;

import com.commonsware.cwac.wakeful.AlarmReceiver;
import com.commonsware.cwac.wakeful.WakefulIntentService;

import java.io.IOException;

public class MyAppListener implements WakefulIntentService.AlarmListener {
    @Override
    public void scheduleAlarms(AlarmManager alarmManager, PendingIntent pendingIntent, Context context) {
        try {
            MyLogManager.write(context, "Beginning of scheduleAlarms\n");
            alarmManager.setExact(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime()+60000, pendingIntent);
            MyLogManager.write(context, "End of scheduleAlarms\n");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void sendWakefulWork(Context context) {
        try {
            MyLogManager.write(context, "Beginning of sendWakefulWork\n");
            WakefulIntentService.sendWakefulWork(context, MyAppService.class);
            MyLogManager.write(context, "End of sendWakefulWork\n");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public long getMaxAge(Context context) {
        return (AlarmManager.INTERVAL_FIFTEEN_MINUTES * 2);
    }
}

MyAppService :

package com.par.hasard.mysimpleapplication;
import android.content.Intent;
import com.commonsware.cwac.wakeful.WakefulIntentService;
import java.io.IOException;

public class MyAppService extends WakefulIntentService {
    public MyAppService(){
        super("MyAppService");
    }

    @Override
    protected void doWakefulWork(Intent intent) {
        try {
            MyLogManager.write(this, "Beginning of doWakefulWork\n");
            MyAlarmPlanner.planAlarm_v2(this);
            MyLogManager.write(this, "End of doWakefulWork\n");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Manifest :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.par.hasard.mysimpleapplication">
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />


    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name="com.par.hasard.mysimpleapplication.MySimpleWakefulReceiver">
            <intent-filter android:priority="1">
                <action android:name="com.par.hasard.mysimpleapplication.REGULAR_ALARM" />
            </intent-filter>
        </receiver>

        <receiver android:name="com.commonsware.cwac.wakeful.AlarmReceiver">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"/>
            </intent-filter>

            <meta-data
                android:name="com.commonsware.cwac.wakeful"
                android:resource="@xml/wakeful"/>
        </receiver>
        <service android:enabled="true" android:name="com.par.hasard.mysimpleapplication.MySimpleWakefulService" />
        <service android:enabled="true" android:name="com.par.hasard.mysimpleapplication.MyAppService" />
    </application>

</manifest>

wakeful.xml :

<WakefulIntentService
    listener="com.par.hasard.mysimpleapplication.MyAppListener"
    />

All this works perfectly, but sometimes, it won't log anything. I think it is due to sleep mode of my phone (Sony Xperia). But it seems to have the same behaviour on other phones. Here's an example of the log :

18/12 2h47m37s304 => Beginning of sendWakefulWork
18/12 2h47m37s311 => End of sendWakefulWork
18/12 2h47m37s316 => Beginning of doWakefulWork
18/12 2h47m37s317 => Beginning of planAlarm_v2
18/12 2h47m37s320 => Beginning of scheduleAlarms
18/12 2h47m37s322 => End of scheduleAlarms
18/12 2h47m37s323 => End of planAlarm_v2
18/12 2h47m37s324 => End of doWakefulWork
18/12 2h48m37s332 => Beginning of sendWakefulWork
18/12 2h48m37s338 => End of sendWakefulWork
18/12 2h48m37s347 => Beginning of doWakefulWork
18/12 2h48m37s348 => Beginning of planAlarm_v2
18/12 2h48m37s350 => Beginning of scheduleAlarms
18/12 2h48m37s351 => End of scheduleAlarms
18/12 2h48m37s352 => End of planAlarm_v2
18/12 2h48m37s353 => End of doWakefulWork
18/12 3h35m6s293 => Beginning of sendWakefulWork    //nothing before ??
18/12 3h35m6s298 => End of sendWakefulWork
18/12 3h35m6s319 => Beginning of doWakefulWork
18/12 3h35m6s327 => Beginning of planAlarm_v2
18/12 3h35m6s331 => Beginning of scheduleAlarms
18/12 3h35m6s338 => End of scheduleAlarms
18/12 3h35m6s340 => End of planAlarm_v2
18/12 3h35m6s345 => End of doWakefulWork
18/12 3h36m7s307 => Beginning of sendWakefulWork
18/12 3h36m7s313 => End of sendWakefulWork
18/12 3h36m7s319 => Beginning of doWakefulWork
18/12 3h36m7s320 => Beginning of planAlarm_v2
18/12 3h36m7s322 => Beginning of scheduleAlarms
18/12 3h36m7s323 => End of scheduleAlarms
18/12 3h36m7s324 => End of planAlarm_v2
18/12 3h36m7s325 => End of doWakefulWork

Can someone help me ?

Answer 1

In terms of the time gap, most likely, you are experiencing Doze mode on Android 6.0+ devices, or the equivalent offered by some manufacturers on older devices (e.g., SONY's STAMINA mode). Other than adding your app to the appropriate whitelist (e.g., for Doze, Settings > Apps > (gear icon) > Special access > Battery optimization), there is very little that you can do.

You are welcome to switch to setExactAndAllowWhileIdle() on API Level 23+ devices, however:

• You will not get control every minute (I think it is limited to every 9 minutes)

• You will not have Internet access when you do get control (which presumably is required for whatever you are trying to do for real)

• This will not help for manufacturer-specific pre-6.0 devices (since that method does not exist)

Overall, designing your app to deal with Doze mode, and not assume that it will get control much in the background, is a more reliable approach.