Question

I’m trying to create an Android application that shows the current time. I want to update time on my Activity with the Timer, but the TextView is not updating, so just one time is always on the screen. Here is my code:

package com.example.androidtemp;

import java.sql.Date;
import java.text.SimpleDateFormat;
import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import com.example.androidtemp.R;

public class ActivityTime extends Activity
{
    SimpleDateFormat sdf;
    String time;
    TextView tvTime;
    String TAG = "States";

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity_time);

        sdf = new SimpleDateFormat("HH:mm:ss");
        time = sdf.format(new Date(System.currentTimeMillis()));

        tvTime = (TextView) findViewById(R.id.tvTime);

        Timer timer = new Timer();
        TimerTask task = new TimerTask()
        {
            @Override
            public void run()
            {
                // TODO Auto-generated method stub
                timerMethod();
            }
        };

        try
        {
            timer.schedule(task, 0, 1000);
        } 
        catch (IllegalStateException e)
        {
            // TODO: handle exception
            e.printStackTrace();
            Log.e(TAG, "The Timer has been canceled, or if the task has been scheduled or canceled.");
        }
    }

    protected void timerMethod()
    {
        // TODO Auto-generated method stub
        this.runOnUiThread(changeTime);
    }

    private  final Runnable changeTime = new Runnable()
    {
        public void run()
        {
            // TODO Auto-generated method stub
            //Log.d(TAG, "Changing time.");
            sdf.format(new Date(System.currentTimeMillis()));
            tvTime.setText(time);
        }
    };
}

Does anyone have solution for this problem?

Answer 1

I would recommend you to use DigitalClock or TextClock (you can use ‘include’ in the layout xml and layout / layout-v17 to use a different component depending of the OS version) if you just want to show the time.

If you want to have more control, I would recommend you using a Handler or an ExecutorService instead of a Timer. Java Timer vs ExecutorService?

If you want to fix your code as it is, just modify the value of the variable ‘time’ 😉