Android - ถ้ากด Button แล้วเรียกใช้งานไฟล์ php บน server จะต้องทำอย่างไรครับ

package com.itp.intentbuiltinapp;

import org.json.JSONObject;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	
//		startActivity(itn);
		
	}

	public void ON (View v) {
		
		String urlStr = "http://10.0.2.2/electical/user/Relay1/ON.php"; 

		Intent itnon = new Intent(android.content.Intent.ACTION_VIEW);
		itnon.setData(Uri.parse(urlStr));
		
		startActivity(itnon);
	}
	
	public void OFF (View v) {
		
		String urlStr = "http://10.0.2.2/electical/user/Relay1/OFF.php"; 

		Intent itnoff = new Intent(android.content.Intent.ACTION_VIEW);
		itnoff.setData(Uri.parse(urlStr));
		
		startActivity(itnoff);
	}
	
//	@Override
//	public boolean onCreateOptionsMenu(Menu menu) {
//		// Inflate the menu; this adds items to the action bar if it is present.
//		getMenuInflater().inflate(R.menu.activity_main, menu);
//		return true;
//	}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

     <Button
         android:id="@+id/button1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"
         android:layout_alignParentTop="true"
         android:layout_marginLeft="54dp"
         android:layout_marginTop="117dp"
         android:onClick="ON"
         android:text=" ON " />

     <Button
         android:id="@+id/button2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignBaseline="@+id/button1"
         android:layout_alignBottom="@+id/button1"
         android:layout_alignParentRight="true"
         android:layout_marginRight="66dp"
         android:onClick="OFF"
         android:text=" OFF " />

</RelativeLayout>