Creating An Android Service

I'm trying to create a service which will start by the user request in the application. After the user will choose an update interval, the service will run in the operation system

Solution 1:

Your toast is not showing because you are not telling it to. Try:

publicvoidshowNotification() {        
    Toast.makeText(this, "Hi", 10).show();
}

For your service issue, I think that you do not properly understand how services & activities work together. A service can run independently of a service, or you can have a service whose lifecycle matches that of a given activity. From your code, it is not clear which of these models you are following. Your implementation will cause the service to wake periodically, but only while your activity is running. If the user switches to another activity, your service will no longer be woken.

If you want a service to wake periodically independently of the activity, then you need to run your timer event in the service itself. Better still use an Alarm to wake your service: Register an Alarm with AlarmManager which will fire an Intent at a future point (or regular intervals, if you prefer), and extend your service from IntentService, override onHandleIntent() and add the necessary Intent Filter to your Service entry in the manifest.