need to find distance between given two cities

I need to find thedistance between two cities?
I have two names of cities. EX Colombo & Galle
I need to write a programe to show these cities google map and need to draw a line between two cities.Also i need to calculate the distance?
can anyone tell me the way or give me simple example.I search through internet.Still not get good one.

Find their latitudes and longitudes. Then implement a calculation which finds the distance between the two lat-long pairs. (That calculation CAN be found on the internet.)

can you tell me how to get longitudes & latitudes of a given citi?

this is my class

package com.android.geo;

import java.io.IOException;
import java.util.List;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;

public class GetGeoCoding extends MapActivity {
	Geocoder geocoder = null;
	MapView mapView = null;

@Override
	protected boolean isLocationDisplayed() {
		return false;
	}

@Override
	protected boolean isRouteDisplayed() {
		return false;
	}

@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.geocode);
		mapView = (MapView) findViewById(R.id.geoMap);
		mapView.setBuiltInZoomControls(true);
		// lat/long of Jacksonville, FL
		int lat = (int) (30.334954 * 1000000);
		int lng = (int) (-81.5625 * 1000000);
		GeoPoint pt = new GeoPoint(lat, lng);
		mapView.getController().setZoom(10);
		mapView.getController().setCenter(pt);

geocoder = new Geocoder(this);
	}

public void doClick(View arg0) {
		try {
			EditText loc = (EditText) findViewById(R.id.location);
			String locationName = loc.getText().toString();
			List<Address> addressList = geocoder.getFromLocationName(
					locationName, 5);
			if (addressList != null && addressList.size() > 0) {
				int lat = (int) (addressList.get(0).getLatitude() * 1000000);
				int lng = (int) (addressList.get(0).getLongitude() * 1000000);
				GeoPoint pt = new GeoPoint(lat, lng);
				mapView.getController().setZoom(15);
				mapView.getController().setCenter(pt);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

This is my xml file

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="fill_parent" android:layout_height="fill_parent">
	<LinearLayout android:layout_width="fill_parent"
		android:layout_alignParentBottom="true" android:layout_height="wrap_content"
		android:orientation="vertical">
		<EditText android:layout_width="fill_parent" android:id="@+id/location"
			android:layout_height="wrap_content" android:text="White House" />
		<Button android:id="@+id/geocodeBtn" android:layout_width="wrap_content"
			android:layout_height="wrap_content" android:onClick="doClick"
			android:text="Find Location" />
	</LinearLayout>

<com.google.android.maps.MapView
		android:id="@+id/geoMap" android:clickable="true"
		android:layout_width="fill_parent" android:layout_height="320px"
		android:apiKey="0C:8B:EE:40:41:C6:77:EC:88:52:C2:D9:64:61:A6:D7" />
</RelativeLayout>
[code]

but when i run i get this error

[code]
09-28 12:05:34.607: WARN/dalvikvm(306): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-28 12:05:34.707: ERROR/AndroidRuntime(306): FATAL EXCEPTION: main
09-28 12:05:34.707: ERROR/AndroidRuntime(306): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.android.geo/com.android.geo.GetGeoCoding}: java.lang.ClassNotFoundException: com.android.geo.GetGeoCoding in loader dalvik.system.PathClassLoader[/data/app/com.android.geo-1.apk]
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.os.Looper.loop(Looper.java:123)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.ActivityThread.main(ActivityThread.java:4627)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at java.lang.reflect.Method.invokeNative(Native Method)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at java.lang.reflect.Method.invoke(Method.java:521)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at dalvik.system.NativeStart.main(Native Method)
09-28 12:05:34.707: ERROR/AndroidRuntime(306): Caused by: java.lang.ClassNotFoundException: com.android.geo.GetGeoCoding in loader dalvik.system.PathClassLoader[/data/app/com.android.geo-1.apk]
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
09-28 12:05:34.707: ERROR/AndroidRuntime(306):     ... 11 more
09-28 12:05:34.857: WARN/ActivityManager(59):   Force finishing activity com.android.geo/.GetGeoCoding
09-28 12:05:35.438: WARN/ActivityManager(59): Activity pause timeout for HistoryRecord{450b00b8 com.android.geo/.GetGeoCoding}

Can anyone tell me why it is giving error ?