<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <Button        android:id="@+id/Basicbtn"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="1"        android:text="BasicBtn"         android:onClick="onMyButtonClick" /></LinearLayout>

package com.skpack.basicBtn;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.Toast;public class MyBasicButtonActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);    }        public void onMyButtonClick(View view){     Toast.makeText(this, "Button clicked!", Toast.LENGTH_SHORT).show();     }    }