SimpleClock

Main.java

package com.mohayonao.SimpleClock;

import java.text.SimpleDateFormat;
import java.util.Date;

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

public class Main extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        main();
    }

    private void main() {
        int interval = 100;
        Handler h = new Handler();
        h.post(new Runnable() {
                private Handler h;
                private int i;
                private TextView t;
                private SimpleDateFormat s;

                public Runnable init(Handler h, int interval) {
                    this.h = h;
                    this.i = interval;
                    this.t = ((TextView)findViewById(R.id.clock));
                    this.s = new SimpleDateFormat("HH:mm:ss.SSS");
                    return this;
                }
                public void run() {
                    t.setText(s.format(new Date()));
                    h.postDelayed(this, i);
                }
            }.init(h, interval));
    }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_height="wrap_content"
    android:id="@+id/clock" android:layout_width="wrap_content" android:layout_centerInParent="true" android:textSize="50dp" android:text="00:00:00.000" android:textStyle="bold"/>
</RelativeLayout>