How to implement delay in android?

Question

I want to print sequential numbers every 2 seconds when I press button. I used following code:

int j=0;
button.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            c=Calendar.getInstance();
            Delay(2 ,c.get(Calendar.SECOND));
            if(j++<5)
              t.setText("number "+j);

            }

    });

public void Delay(int p,int q){

    int z=0;

    while(z<p){
        c=Calendar.getInstance();
        i= c.get(Calendar.SECOND);
        z=i-q;
    }

    return ;
}

but this code prints "Number 5" at the end of 10 seconds directly. How can I print "Number 1", "Number 2", "Number 3"....sequentially every 2 sec.

read there http://stackoverflow.com/questions/18702298/android-how-to-run-an-asynctask-every-second — Marcin Mikołajczyk, Aug 21 '14 at 13:41
You're blocking the UI thread for ten seconds... You mustn't do that. You should use an AsyncTask / use a new thread, check this link. http://developer.android.com/reference/android/os/AsyncTask.html — Jose Antonio Benitez Montero, Aug 21 '14 at 14:14

score 1 · Answer 1 · answered Aug 21 '14 at 13:39

Note that if you're doing this on UI thread, you'll be blocking the UI thread for 10 seconds. It's much better to have a separate thread to do this:

button.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
        new Thread() {
            public void run() {
                for(int j=1; j<=5; i++) {
                     runOnUiThread(new Runnable() {
                         @Override
                         public void run() { t.setText("number " + j); }
                    });
                    SystemClock.sleep(2000);
                }
            }
        }.start();
    }
});

This code starts a new thread (thus not blocking the UI), which iterates from 1 to 5 outputting the number (on UI thread, as it's changing the UI) and then sleeps for 2 seconds.

score 0 · Answer 2 · answered Aug 21 '14 at 13:41

Use a Runnable to post to a handler bound to the UI thread for your app rather than sleep or delay. If you sleep or delay in your onClick() method, you are blocking the UI thread and it will make your UI unresponsive.

public class MyActivity extends Activity implements Handler.Callback {
    ...
    private Handler mHandler = new Handler(this);
    private int     mNumber = 0;
    ...
    @Override
    public void onClick(View v) {
        mNumber++;
        mHandler.postDelayed(new Runnable() {
            public void run() {
                t.setText("number: " + mNumber);
            }, 2000);
    }
}

score 0 · Answer 3 · answered Aug 21 '14 at 13:58

You can use the CountDownTimer for this..you just have to define the amount of time and how often you want to update. You just have to adjust the logic a bit to do print the numbers upward.

button.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
    new CountDownTimer(60000, 2000) {

       public void onTick(long millisUntilFinished) {
           mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
       }

       public void onFinish() {
         mTextField.setText("done!");
       }
    }.start();
}
});

How to implement delay in android?

3 Answers3