Android กับ Dialog boxes การโต้ตอบเบื้องต้นกับ AlertDialog และ makeText(Toast)

package com.myapp;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;
import android.widget.Button;
import android.app.AlertDialog;


public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        final AlertDialog.Builder adb = new AlertDialog.Builder(this);
        
        // button
        final Button btn1 = (Button) findViewById(R.id.button1);
        // Input Text
        final TextView editT1 = (TextView)findViewById(R.id.editText1);
        // Perform action on click
        btn1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                AlertDialog ad = adb.create();
                String strTxt = editT1.getText().toString();
                //ad.setMessage(editTxt.getText());
                ad.setMessage("Sawatdee khun : " + strTxt);
                ad.show();
            }
        });
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        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" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="18dp"
        android:text="Please input Your Name ?" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView1"
        android:layout_centerHorizontal="true"
        android:ems="10"
        android:inputType="textPersonName" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="15dp"
        android:text="Button" />

</RelativeLayout>