How to perform a method in a given time?

Question

I need that at certain programmed hours, a method is executed even if the user is outside the application.So I searched I will have to use services?
I didn’t quite understand how to program time, I just left the class created here:

public class Notificacao extends Service {


public void onCreate() {

    super.onCreate();

}

@Override

public int onStartCommand(Intent intent, int flags, int startId) {

    //fez_algo

    Toast.makeText(Notificacao.this, "Fez algo", 1000).show();
    return START_STICKY;

}

But how to execute a method , every 1 hour for example? this method can be declared in the same service class, someone tells me the simplest way?

Answer 1

Use a BroadcastReceiver along with AlarmManager. In the method onReceiveof BroadcastReceiver have the scheduled task executed.

public class ExecutarTarefaProgramadaReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {

        //      Código a executar
    }

}  

To start the process use this code:

//Definir a hora de início
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 10);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);

Intent tarefaIntent = new Intent(context, ExecutarTarefaProgramadaReceiver.class);
PendingIntent tarefaPendingIntent = PendingIntent.getBroadcast(context,1234, tarefaIntent,0);

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

//Definir o alarme para acontecer todos os dias às 10 horas
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
                 AlarmManager.INTERVAL_DAY, tarefaPendingIntent);  

Do not forget to record the BroadcastReceiver in the Androidmanifest.xml

<receiver android:name="a_sua_package.ExecutarTarefaProgramadaReceiver"/>  

See the documentation of Alarmmanager to know how to define other time intervals.

To run 4x per day(every 6 hours), starting at 10 o'clock:

//Definir início para as 10 horas
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 10);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);

//Definir intervalo de 6 horas
long intervalo = 6*60*60*1000; //6 horas em milissegundos

Intent tarefaIntent = new Intent(context, ExecutarTarefaProgramadaReceiver.class);
PendingIntent tarefaPendingIntent = PendingIntent.getBroadcast(context,1234, tarefaIntent,0);

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

//Definir o alarme para acontecer de 6 em 6 horas a partir das 10 horas
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
                 intervalo, tarefaPendingIntent);

If the task to execute is time consuming, instead of a Boadccast receiver use a service to run it.
This reply shows a possible implementation. The code to be executed must be placed in the method onHandleIntent().
The implementation handles the device’s status being turned off, re-plotting the task while being turned on.