package com.example.devang.exno3; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.text.TextUtils; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button;

import android.widget.EditText; import android.widget.TextView; public class MainActivity extends AppCompatActivity implements OnClickListener { //Defining the Views EditText Num1; EditText Num2; Button Add; Button Sub; Button Mul; Button Div; TextView Result; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //Referring the Views Num1 = (EditText) findViewById(R.id.editText1); Num2 = (EditText) findViewById(R.id.editText2); Add = (Button) findViewById(R.id.Add); Sub = (Button) findViewById(R.id.Sub); Mul = (Button) findViewById(R.id.Mul); Div = (Button) findViewById(R.id.Div); Result = (TextView) findViewById(R.id.textView);

// set a listener Add.setOnClickListener(this); Sub.setOnClickListener(this); Mul.setOnClickListener(this); Div.setOnClickListener(this); } @Override public void onClick (View v) { float num1 = 0; float num2 = 0; float result = 0; // check if the fields are empty if (TextUtils.isEmpty(Num1.getText().toString()) || TextUtils.isEmpty(Num2.getText().toString())) return; // read EditText and fill variables with numbers num1 = Float.parseFloat(Num1.getText().toString()); num2 = Float.parseFloat(Num2.getText().toString()); // defines the button that has been clicked and performs the corresponding operation // write operation into oper, we will use it later for output switch (v.getId()) { case R.id.Add: oper = "+";

result = num1 + num2; break; case R.id.Sub: oper = "-"; result = num1 - num2; break; case R.id.Mul: oper = "*"; result = num1 * num2; break; case R.id.Div: oper = "/"; result = num1 / num2; break; default: break; } // form the output line Result.setText(num1 + " " + oper + " " + num2 + " = " + result); } }