Activity Life Cycle

This will show you the life cycle of an activity :)

This diagram is showing you the life cycle of an activity.
 To Understand it more clearly just follow following steps:
 Step 1:
Create a new project by any name you want.

Paste Following code in the MainActivity File.


import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

/**
 * Lab 1 - Activity Lifecycle
 *
 * @author Tadas Valaitis
 *
 * @see http://developer.android.com/training/basics/activity-lifecycle/index.html
 * @see http://developer.android.com/guide/components/activities.html
 * @see http://developer.android.com/reference/android/app/Activity.html
 *
 *
 */
public class MainActivity extends Activity {

protected static final String TAG = "MainActivity";

/**
* Called when the activity is first created. This is where you should do
* all of your normal static set up Ñ create views, bind data to lists, and
* so on.
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "onCreate(Bundle savedInstanceState)");
}

/**
* Called after the activity has been stopped, just prior to it being
* started again.
*/
@Override
protected void onRestart() {
Log.d(TAG, "onRestart()");
super.onRestart();

}

/**
* Called just before the activity becomes visible to the user.
*/
@Override
protected void onStart() {
// TODO Auto-generated method stub
Log.d(TAG, "onStart()");
super.onStart();
}

/**
* This method is called after onStart() when the activity is being
* re-initialized from a previously saved state, given here in
* savedInstanceState
*/
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
// TODO Auto-generated method stub
Log.d(TAG, "onRestoreInstanceState(Bundle savedInstanceState)");
super.onRestoreInstanceState(savedInstanceState);
}

/**
* Called just before the activity starts interacting with the user.
*/
@Override
protected void onResume() {
Log.d(TAG, "onResume()");
super.onResume();

}

/************************* ACTIVITY IS CREATED AND INTERACTING WITH USER ***************************/

/**
* Called when the system is about to start resuming another activity.
*/
@Override
protected void onPause() {
Log.d(TAG, "onPause()");
super.onPause();

}

/**
* Called when the activity is no longer visible to the user. This may
* happen because it is being destroyed, or because another activity (either
* an existing one or a new one) has been resumed and is covering it.
*/
@Override
protected void onStop() {
// TODO Auto-generated method stub
Log.d(TAG, "onStop()");
super.onStop();
}

/**
* The system calls onSaveInstanceState() before making the activity
* vulnerable to destruction
*
* Not called when Back button pressed
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
// TODO Auto-generated method stub
Log.d(TAG, "onSaveInstanceState(Bundle outState)");
super.onSaveInstanceState(outState);
}

/**
* Called before the activity is destroyed. This is the final call that the
* activity will receive.
*/
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
Log.d(TAG, "onDestroy()");
super.onDestroy();
}

/********** ACTIVITY IS DESTROYED *******/

}


Step 2:

Paste Following code into xml file

<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" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>


And Run the android Application.