Android Timer example

package com.example.androidtimer;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.os.Handler;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {

private Button startButton;
private Button pauseButton;

private TextView timerValue;

private long startTime = 0L;

private Handler customHandler = new Handler();

long timeInMilliseconds = 0L;
long timeSwapBuff = 0L;
long updatedTime = 0L;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

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

startButton = (Button) findViewById(R.id.startButton);

startButton.setOnClickListener(new View.OnClickListener() {

                        public void onClick(View view) {

startTime = SystemClock.uptimeMillis();
customHandler.postDelayed(updateTimerThread, 0);
}
});

pauseButton = (Button) findViewById(R.id.pauseButton);

pauseButton.setOnClickListener(new View.OnClickListener() {

public void onClick(View view) {

timeSwapBuff += timeInMilliseconds;
customHandler.removeCallbacks(updateTimerThread);
}
});
}

private Runnable updateTimerThread = new Runnable() {

public void run() {

timeInMilliseconds = SystemClock.uptimeMillis() - startTime;

updatedTime = timeSwapBuff + timeInMilliseconds;

int secs = (int) (updatedTime / 1000);
int mins = secs / 60;
secs = secs % 60;
int milliseconds = (int) (updatedTime % 1000);
timerValue.setText("" + mins + ":"
+ String.format("%02d", secs) + ":"
+ String.format("%03d", milliseconds));
customHandler.postDelayed(this, 0);
}
};
}