Calculator - Android Example

         

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                         XML Code

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<LinearLayout 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"

    android:orientation="vertical"

    >

<EditText

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/num1"

    android:hint="First Number"

    />

<EditText

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/num2"

    android:hint="Second Number"

    />

<EditText

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/res"

    android:hint="Result "

    />

<Button

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/add"

    android:text="Add"

    android:onClick="perfrom"

    />

<Button

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/sub"

    android:text="Sub"

    android:onClick="perfrom"

    />

<Button

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/mul"

    android:text="mul"

    android:onClick="perfrom"

    />

<Button

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:id="@+id/div"

    android:text="div"

    android:onClick="perfrom"

    />

</LinearLayout>

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                       Java Code

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package com.example.calculator;

import android.app.Activity;

import android.os.Bundle;

import android.view.Menu;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

public class MainActivity extends Activity {

       EditText e1,e2,e3;

       int n1,n2,ans;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

       

        e1 = (EditText)findViewById(R.id.num1);

        e2 = (EditText)findViewById(R.id.num2);

        e3 = (EditText)findViewById(R.id.res);

       

    }

    @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;

    }

   

    public void perfrom(View v)

    {

       Button b = (Button)v;

      

       n1 = Integer.parseInt(e1.getText().toString());

       n2 = Integer.parseInt(e2.getText().toString());

      

       switch(b.getId())

       {

              case R.id.add:

                                  ans=n1+n2;

                                  e3.setText(ans + "");

                                  break;

              case R.id.sub:

                                  ans=n1-n2;

                                  e3.setText(ans + "");

                                  break;

              case R.id.mul:

                                  ans=n1*n2;

                                  e3.setText(ans + "");

                                  break;

              case R.id.div:

                                  ans=n1/n2;

                                  e3.setText(ans + "");

                                  break;

                                               

       }

    }

   

}