How to add two number in Kotlin

MainActivity.java

package com.example.deep.kotlindemo import android.support.v7.app.AppCompatActivity import android.os.Bundle import android.text.TextUtils import android.view.View import android.widget.EditText import android.widget.TextView import android.widget.Toast class MainActivity : AppCompatActivity() { lateinit var t1: EditText lateinit var t2: EditText override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) t1 = findViewById(R.id.first) t2 = findViewById(R.id.second) } fun submit(v: View) { if (TextUtils.isEmpty(t1.text.toString())) { t1.setError("Fill this field") } else if (TextUtils.isEmpty(t2.text.toString())) { t2.setError("Fill this field") } else { var i = Integer.parseInt(t1.text.toString()); var j = Integer.parseInt(t2.text.toString()); var c=i+j; Toast.makeText(this,"Output is : $c",Toast.LENGTH_LONG).show() } } }

activity_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:layout_margin="10dp" android:orientation="vertical"> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center" android:padding="20dp" android:text="Kotlin Add" android:textColor="#000" android:layout_marginTop="10dp" android:textSize="30sp" android:typeface="serif" /> <EditText android:id="@+id/first" android:layout_marginTop="10dp" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Enter First Number" android:inputType="number" android:padding="20dp" /> <EditText android:id="@+id/second" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Enter Second Number" android:layout_marginTop="10dp" android:inputType="number" android:padding="20dp" /> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:onClick="submit" android:layout_marginTop="10dp" android:text="Add" android:padding="20dp"/> </LinearLayout>

manifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.deep.kotlindemo"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>