How do I use the service on Android Top 5 - service

Question

I've used a service in my program but the top 5 Android phone goes to sleep as soon as the service does nothing.
It works on Android 4 without any problems.
pls help me.
in Activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
startService(new Intent(this , MyService.class));
}
}
in Service
public class MyService extends android.app.Service {
private PowerManager pm;
private WifiManager wm;
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
//do something code
return START_STICKY;
}
#Override
public void onTaskRemoved(Intent rootIntent) {
if (android.os.Build.VERSION.SDK_INT >= 21) {
pm = (PowerManager) getApplicationContext().getSystemService(Context.POWER_SERVICE);
final PowerManager.WakeLock wakeLock = pm.newWakeLock((PowerManager.PARTIAL_WAKE_LOCK), "TAG");
wakeLock.acquire();
wm = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
WifiManager.WifiLock lock = wm.createWifiLock(WifiManager.WIFI_MODE_FULL, "LockTag");
lock.acquire();
Intent restartServiceIntent = new Intent(getApplicationContext(),
MyService.class);
restartServiceIntent.setPackage(getPackageName());
PendingIntent restartServicePendingIntent = PendingIntent.getService(
getApplicationContext(), 0, restartServiceIntent,
PendingIntent.FLAG_ONE_SHOT);
AlarmManager alarmService = (AlarmManager) getApplicationContext()
.getSystemService(Context.ALARM_SERVICE);
long thirtySecondsFromNow = 1000;
alarmService.set(AlarmManager.RTC_WAKEUP, thirtySecondsFromNow, restartServicePendingIntent);
ComponentName receiver = new ComponentName(getApplicationContext(), MyService.class);
PackageManager pm = getApplicationContext().getPackageManager();
pm.setComponentEnabledSetting(receiver,
PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
PackageManager.DONT_KILL_APP);
super.onTaskRemoved(rootIntent);
}
}
}
in Manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="app.service">
<uses-permission android:name="android.permission.WAKE_LOCK" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
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>
<service
android:name=".MyService"
android:enabled="true"
android:exported="false"
android:label="my"
android:largeHeap="true"
android:stopWithTask="false" />
</application>