AIDE Tutorial - 55 BMI Calculator

AIDE Tutorial - 55 BMI Calculator
Watch the video below

Main xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<TextView
android:layout_marginBottom="20dp"
android:textSize="25dp"
android:text="BMI Calculator"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"/>

<EditText
android:inputType="number|numberDecimal"
android:layout_marginBottom="20dp"
android:maxLength="3"
android:id="@+id/edittext1"
android:hint="Enter your Weight  here [Kg]"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<EditText
android:inputType="number|numberDecimal"
android:layout_marginBottom="20dp"
android:maxLength="3"
android:id="@+id/edittext2"
android:hint="Enter your Height here [M]"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<Button
android:layout_marginBottom="20dp"
android:id="@+id/calculate"
android:text="Calculate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<TextView
android:layout_marginBottom="20dp"
android:id="@+id/textview"
android:text=""
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>

MainActivity.java
package com.kcgroup.bmicalculator;

import android.app.*;
import android.os.*;
import android.widget.*;
import android.view.*;

public class MainActivity extends Activity
{private EditText et1,et2;
private Button btn;
private TextView tv;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

et1=(EditText)findViewById(R.id.edittext1); et2=(EditText)findViewById(R.id.edittext2);
btn=(Button)findViewById(R.id.calculate); tv=(TextView)findViewById(R.id.textview);

btn.setOnClickListener(new View.OnClickListener(){

@Override
public void onClick(View p1)
{
double a=Double.parseDouble(et1.getText().toString());
double b=Double.parseDouble(et2.getText().toString());
double ans= a/(b*b); tv.setText(String.valueOf(ans)); } });

}}