Activity lifecycle

An activity represents a single screen with a user interface the other words activity is a visible screen.

Mostly activity lifecycle containing more methods.

Descrption of all lifecycle methods          

onCreate() -> This is the first callback and called when the activity is first created.

onStart()  -> This callback is called when the activity becomes visible to the user.

onResume() -> Called when the activity starts interacting with the user

onPause()  -> Called when the current activity is being paused and the previous activity is being                                resumed

onStop()  -> This callback is called when the activity is no longer visible.

onDestroy()  ->This callback is called before the activity is destroyed by the system

onRestart() -> This callback is called when the activity restarts after stopping it.

ActivityMain.java 

 public class MainActivity extends Activity {

   String str = "Android Call : ";

   

   /** Called when the activity is first created. */

   @Override

   public void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.activity_main);

      Log.e(str, "onCreate() event");

   }

   /** Called when the activity is about to become visible. */

   @Override

   protected void onStart() {

      super.onStart();

      Log.d(str, "onStart() event");

   }

   /** Called when the activity has become visible. */

   @Override

   protected void onResume() {

      super.onResume();

      Log.d(str, "onResume() event");

   }

   /** Called when another activity is focus. */

   @Override

   protected void onPause() {

      super.onPause();

      Log.d(str, "onPause() event");

   }

   /** Called when the activity is no longer visible. */

   @Override

   protected void onStop() {

      super.onStop();

      Log.d(str, "onStop() event");

   }

   /** Called just before the activity is destroyed. */

   @Override

   public void onDestroy() {

      super.onDestroy();

      Log.d(str, "onDestroy() event");

   }

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/linearLayout1"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="I'm screen 1"

        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

   package="com.samset.activitysample"

   android:versionCode="1"

   android:versionName="1.0" >

   

   <uses-sdk

      android:minSdkVersion="8"

      android:targetSdkVersion="22" />

   

   <application

       android:icon="@drawable/ic_launcher"

       android:label="@string/app_name"

       android:theme="@style/AppTheme" >

       

       <activity

          android:name=".MainActivity"

          android:label="@string/title_activity_main" >

          

          <intent-filter>

             <action android:name="android.intent.action.MAIN" />

             <category android:name="android.intent.category.LAUNCHER"/>

          </intent-filter>

          

       </activity>

       

   </application>

</manifest>

Thank you