Android working with buttons and Edit text

Step 1 :

Make a project.

Step 2 :

Paste the following code in MailActivity.java file.

package com.example.buttonexample;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class MainActivity extends Activity {

       private EditText edittext1, edittext2;

       private Button buttonSum;

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              super.onCreate(savedInstanceState);

              setContentView(R.layout.activity_main);

              addListenerOnButton();

       }

       public void addListenerOnButton() {

              edittext1 = (EditText) findViewById(R.id.editText1);

              edittext2 = (EditText) findViewById(R.id.editText2);

              buttonSum = (Button) findViewById(R.id.button1);

              buttonSum.setOnClickListener(new OnClickListener() {

                     @Override

                     public void onClick(View view) {

                           String value1 = edittext1.getText().toString();

                            String value2 = edittext2.getText().toString();

                           int a = Integer.parseInt(value1);

                           int b = Integer.parseInt(value2);

                           int sum = a + b;

                           Toast.makeText(getApplicationContext(), String.valueOf(sum),

                                         Toast.LENGTH_LONG).show();

                     }

              });

       }

}

Step 3 :

Paste the fllowing code in activity_main.xml file.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

    <EditText

        android:id="@+id/editText1"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:ems="10"

        android:hint="Enter first value" />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:ems="10"

        android:hint="Enter second value" >

        <requestFocus />

    </EditText>

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_centerHorizontal="true"

        android:layout_centerVertical="true"

        android:layout_marginLeft="115dp"

        android:text="Click" />

</LinearLayout>