Android: execute code in regular intervals

I need to perform some code in regular intervals (connect to a server and pull data from MySQL database every minute). For this purpose I have a Sync class:

public class Sync {

    static private Handler handler = new Handler();
    Runnable task;

    public Sync(Runnable task, long time) {
        this.task = task;
        handler.removeCallbacks(task);
        handler.postDelayed(task, time);
    }
}

and in my Activity I have:

public void onCreate(Bundle savedInstanceState) {
    ...
    Sync sync = new Sync(call,60*1000);
    ...
}

final private Runnable call = new Runnable() {
    public void run() {
    //This is where my sync code will be, but for testing purposes I only have a Log statement
    Log.v("test","this will run every minute");
    }
};

I have tried this with a shorter time period for testing, but It only runs once. When it Logs the message for the first time, its also the last. Does anyone see what Im doing erong here? Thanks!


Solution 1:

You can do that using the below code, Hope it helps!

final Handler handler = new Handler(); 
Runnable runnable = new Runnable() { 

    @Override 
    public void run() { 
        try{
            //do your code here
        }
        catch (Exception e) {
            // TODO: handle exception
        }
        finally{
            //also call the same runnable to call it at regular interval
            handler.postDelayed(this, 1000); 
        }
    } 
}; 

//runnable must be execute once
handler.post(runnable);

Solution 2:

First you have to declare handler globally Second you have to use post Delay method again in runnable to trigger it again.

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Sync sync = new Sync(call,60*1000);

    }
    final private Runnable call = new Runnable() {
        public void run() {
        //This is where my sync code will be, but for testing purposes I only have a Log statement
        Log.v("test","this will run every minute");
        handler.postDelayed(call,60*1000);
        }
    };
    public final Handler handler = new Handler();
    public class Sync {


        Runnable task;

        public Sync(Runnable task, long time) {
            this.task = task;
            handler.removeCallbacks(task);
            handler.postDelayed(task, time);
        }
    }


}

Solution 3:

handler.postDelayed(task, time); will only execute once, if you want the code to trigger at regular intervals I would suggest a Timer and a TimerTask instead of a Handler and a Runnable.

TimerTasks can be set to run once, every x seconds, or with a fixed period e.g. x seconds - however long it took to run last time.