A simple activity that has all it needs to be regularly updated while on screen.

MainActivity.java

package com.example.uiupdatetest;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.widget.TextView;

public class MainActivity extends Activity {
	TextView tv;
	Timer updateTimer;
	int counter = 0;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		tv = (TextView) findViewById(R.id.textview);
	}

	@Override
	protected void onStart() {
		super.onStart();
		updateTimer = new Timer();
		updateTimer.schedule(new updateTask(new Handler(), this), 0, 1000);
	}

	@Override
	protected void onStop() {
		super.onStop();
		updateTimer.cancel();
		updateTimer.purge();
	}
	
	public void update() {
		// This is where the UI calls go
		tv.setText(String.valueOf(++counter));
	}
	
	private class updateTask extends TimerTask {
		Handler handler;
		MainActivity ref;
		
		public updateTask(Handler handler, MainActivity ref) {
			super();
			this.handler = handler;
			this.ref = ref;
		}
		
		@Override
		public void run() {
			handler.post(new Runnable() {				
				@Override
				public void run() {
					ref.update();
				}
			});
		}	
	}
}