Addition of Two number in android

Step1:

           Create a new project. 

          Go to File => Project => Android Project =>Next=>Target SDK =>Next => Give class name & package=> Finish.

Step2:

        Here I am taking Java file name as “Main.java”. Now you open main.xml file. As per the program we will take two integer number and after clicking add button,the result will show on the text view in same page.

Step3:

   Go to your main.xml file. Take two edit text. See just drag & drop into xml file. Add a button also. Add a TextView in Last.

See Here main.xml

<?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" >

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="Addition of 2 number"

        android:gravity="center" />

    <EditText

        android:id="@+id/editText1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:inputType="textPersonName" >

        <requestFocus />

    </EditText>

    <EditText

        android:id="@+id/editText2"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:inputType="textPersonName" />

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="ADD" />

<TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Large Text"

        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

Step4:

   Now go to your Main.java File. We need to write the code for adding two numbers.Let’s see how to do it.

Observe setContentView(R.layout.main);. Here it is calling main.xml file from java file. So we need to call Button , EditText, TextView in Java file that we designed in main.xml

So we need to create instance for Button , EditText, TextView in Java.

Just follow this piece of code:

final Button btn = (Button)findViewById(R.id.button1);

final EditText et1 = (EditText)findViewById(R.id.editText1);

final EditText et2 = (EditText)findViewById(R.id.editText2);

final TextView result = (TextView)findViewById(R.id.textView1)

When ever you are calling Button or EditText or TextView in java file from xml file,we can call it by using id.

<Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="ADD" />

Here id is button1. How it’s using in java file. Write Button  <somename> = (Button)findViewById(R.id.button1).

By using findViewById it will search how many id is there in xml file.You need to choose that ID(for Button id is button1).This is the same case for EditText, TextView.

Now what we want  to do?? We want to add two number when we click the button. So when we clicking, some listener is needed for click. So for clicking on button listener is setOnClickListener. How we use it??

btn.setOnClickListener(new OnClickListener()

        {

                 

                  @Override

                  public void onClick(View v)

                  {

                  }

            });

After creating button instance, we have to use setOnClickListener. Just type it & put new & then <ctrl+space>,then select OnClickListener(). It will show some error. Just click that point,it will ask for import.Just click on that & put ; in the last.

Now see this piece of code:

int x = new Integer(et1.getText().toString());

int y = new Integer(et2.getText().toString());

int sum = x + y;

result.setText("The Sum of "+x+" and "+y+" is "+sum);

Here we are taking two integer number x & y. In that x & y we are callling that EditText object and after getting the value(getText()) converting into the String.We are adding x & Y and storing in sum. After that showing the result.

Main.java

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.TextView;

public class Main extends Activity

{

    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState)

    {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

       

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

        final EditText et1 = (EditText)findViewById(R.id.editText1);

        final EditText et2 = (EditText)findViewById(R.id.editText2);

        final TextView result = (TextView)findViewById(R.id.textView1);

        btn.setOnClickListener(new OnClickListener()

        {

                 

                  @Override

                  public void onClick(View v)

                  {

                        int x = new Integer(et1.getText().toString());

                        int y = new Integer(et2.getText().toString());

                        int sum = x + y;

                        result.setText("The Sum of "+x+" and "+y+" is "+sum);

                  }

            });

    }

}

Step5: <<OUTPUT>>