Various Activity Life Phases of Android Application

FileName: activity_main.xml

<RelativeLayout
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"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:background="#CF3A24">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Mycurlycode"
        android:id="@+id/textView"
        android:textColor="#FCC9B9"
        android:textSize="30sp"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

FileName: MainActivity.java

package com.example.abbu.myapplication;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.util.Log;

public class MainActivity extends ActionBarActivity {

    private static final String TAG = "mycurlycodeMessage";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.i(TAG,"onCreate");
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.i(TAG, "onStart");
    }


    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "onResume");
    }


    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "onPause");
    }


    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "onStop");
    }


    @Override
    protected void onRestart() {
        super.onRestart();
        Log.i(TAG, "onRestart");
    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "onDestroy");
    }


    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        Log.i(TAG, "onSaveInstanceState");
    }


    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        Log.i(TAG, "onRestoreInstanceState");
    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}


FileName: strings.xml

<resources>
    <string name="app_name">My Application</string>
    <string name="action_settings">Settings</string>
</resources>

Output:


Various Activity Life Phases of Android Application
As soon as we click on Android Application Icon, the Launcher or Main Activity starts and it calls:
onCreate, onStart and OnResume methods on start of Android Application
Now, when we click on home Button, it calls:
onPause, onSaveInstanceState and onStop methods on clicking home button
When we again click on home button and restart that Android Application, it calls:
onRestart, onStart and onResume methods on again clicking on home button and selecting that particular application
For Landscape Orientation, it calls:
Methods called on Landscape Orientation.
For Portrait Orientation, it calls:
Methods called in Portrait Orientation.
Finally, when we click on back button, it calls:
onDestroy on clicking back button.