My First Android app MainActivity.java file

package com.aupadhyay.myfirstapp;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    EditText editTextName, editTextPhone;
    Button btnSubmit;

    void initViews()
    {
        editTextName = (EditText)findViewById(R.id.editTextName);
        editTextPhone = (EditText)findViewById(R.id.editTextPhone);

        btnSubmit = (Button)findViewById(R.id.button);

        btnSubmit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) { // v = btnSubmit;
                String strName = editTextName.getText().toString().trim();
                String strPhone = editTextPhone.getText().toString().trim();

                Toast.makeText(MainActivity.this, "You Entered : "+strName+" : "+strPhone, Toast.LENGTH_LONG).show();

            }
        });
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
        Toast.makeText(this, "MainActivity - onCreate",Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onStart() {
        super.onStart();
        Toast.makeText(this, "MainActivity - onStart",Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onResume() {
        super.onResume();
        Toast.makeText(this, "MainActivity - onResume",Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onPause() {
        super.onPause();
        Toast.makeText(this, "MainActivity - onPause",Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onStop() {
        super.onStop();
        Toast.makeText(this, "MainActivity - onStop",Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Toast.makeText(this, "MainActivity - onDestroy",Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Toast.makeText(this, "MainActivity - onRestart",Toast.LENGTH_SHORT).show();
    }
}