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 ?
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.