Activities Life Cycle in Android

Activity Introduction

An Activity is a sub-container within an application container that describes all the UI controls.

Every Container has a life cycle (methods) that determine the phase's Activity.

To create an Activity in Android we have to extend the Activity class.

How to work with an Activity

An Image view of an Activity's life cycle:

 

The following is the source code.

MainActivity.java

package com.Saving.savingactivity;

 

import android.os.Bundle;

import android.app.Activity;

//import android.view.Menu;

import android.widget.Toast;

 

public class MainActivity extends Activity {

 

      @Override

      protected void onRestoreInstanceState(Bundle savedInstanceState) {

            super.onRestoreInstanceState(savedInstanceState);

Toast.makeText(getBaseContext(), "Restored ", Toast.LENGTH_LONG).show();

      };

      @Override

      protected void onStart() {

            // TODO Auto-generated method stub

            super.onStart();

            Toast.makeText(getBaseContext(), "Started ", Toast.LENGTH_LONG).show();

      }

      @Override

      protected void onResume() {

            // TODO Auto-generated method stub

            super.onResume();

            Toast.makeText(getBaseContext(), "Resumed ", Toast.LENGTH_LONG).show();

      }

      @Override

      protected void onPause() {

            // TODO Auto-generated method stub

            super.onPause();

            Toast.makeText(getApplicationContext(), "Paused ", Toast.LENGTH_LONG).show();

      }

      @Override

      protected void onSaveInstanceState(Bundle outState) {

            // TODO Auto-generated method stub

            super.onSaveInstanceState(outState);

            Toast.makeText(getApplicationContext(), "Saved ", Toast.LENGTH_LONG).show();

      }

      @Override

      protected void onStop() {

            // TODO Auto-generated method stub

            super.onStop();

            Toast.makeText(getApplicationContext(), "Stoped ", Toast.LENGTH_LONG).show();

      }

      @Override

      protected void onDestroy() {

            // TODO Auto-generated method stub

            super.onDestroy();

            Toast.makeText(getApplicationContext(),"Destroy ", Toast.LENGTH_LONG).show();

      }

 

}

 

Activity_main.xml

<LinearLayout 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"

    tools:context=".MainActivity"

    android:layout_centerHorizontal="true"

     android:layout_centerVertical="true"> 

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="@string/hello_world" />

 

</LinearLayout>

Step 1

 First of all an Activity is creates on a pre-defined Layout by the "onCreate" method.

Step 2

 After that the Activity will start in the "onStart" method.

Step 3

After starting the "onResume" method displays your current UI.

Step 4

After "onResume" if we kill or auto kill the UI then the UI calls the "onPause" method.

 

Step 5

After "onPause" for the current UI, the UI call goes to the "onSave" method.

 

Step 6

The "onSave" method may be called after "onPause" or "onStop"; it depends on the condition in which the UI is killed.

 

Step 7

If we kill the process or active UI then that goes directly to destroy (without saving the current UI ) by the "onDestroy" method.

Otherwise it goes to "onStop" (step 4).