android java activity lifecycle

android java activity lifecycle.

File: activity_main.xml

1. <?xml version="1.0" encoding="utf-8"?>  
2. <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"  
3.     xmlns:app="http://schemas.android.com/apk/res-auto"  
4.     xmlns:tools="http://schemas.android.com/tools"  
5.     android:layout_width="match_parent"  
6.     android:layout_height="match_parent"  
7.     tools:context="example.nowlearn.com.activitylifecycle.MainActivity">  
8.   
9.     <TextView  
10.         android:layout_width="wrap_content"  
11.         android:layout_height="wrap_content"  
12.         android:text="Hello World!"  
13.         app:layout_constraintBottom_toBottomOf="parent"  
14.         app:layout_constraintLeft_toLeftOf="parent"  
15.         app:layout_constraintRight_toRightOf="parent"  
16.         app:layout_constraintTop_toTopOf="parent" />  
17.   
18. </android.support.constraint.ConstraintLayout>  

Android Activity Lifecycle Example

It provides the details about the invocation of life cycle methods of activity. In this example, we are displaying the content on the logcat.

File: MainActivity.java

1. package example.nowlearn.com.activitylifecycle;  
2.   
3. import android.app.Activity;  
4. import android.os.Bundle;  
5. import android.util.Log;  
6.   
7. public class MainActivity extends Activity {  
8.   
9.     @Override  
10.     protected void onCreate(Bundle savedInstanceState) {  
11.         super.onCreate(savedInstanceState);  
12.         setContentView(R.layout.activity_main);  
13.         Log.d("lifecycle","onCreate invoked");  
14.     }  
15.     @Override  
16.     protected void onStart() {  
17.         super.onStart();  
18.         Log.d("lifecycle","onStart invoked");  
19.     }  
20.     @Override  
21.     protected void onResume() {  
22.         super.onResume();  
23.         Log.d("lifecycle","onResume invoked");  
24.     }  
25.     @Override  
26.     protected void onPause() {  
27.         super.onPause();  
28.         Log.d("lifecycle","onPause invoked");  
29.     }  
30.     @Override  
31.     protected void onStop() {  
32.         super.onStop();  
33.         Log.d("lifecycle","onStop invoked");  
34.     }  
35.     @Override  
36.     protected void onRestart() {  
37.         super.onRestart();  
38.         Log.d("lifecycle","onRestart invoked");  
39.     }  
40.     @Override  
41.     protected void onDestroy() {  
42.         super.onDestroy();  
43.         Log.d("lifecycle","onDestroy invoked");  
44.     }  
45. }  

Output: try check...