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

package com.example.activitylifecycle; import android.os.Bundle; import android.app.Activity; import android.util.Log; import android.view.Menu; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Log.d("lifecycle","onCreate invoked"); } @Override protected void onStart() { super.onStart(); Log.d("lifecycle","onStart invoked"); } @Override protected void onResume() { super.onResume(); Log.d("lifecycle","onResume invoked"); } @Override protected void onPause() { super.onPause(); Log.d("lifecycle","onPause invoked"); } @Override protected void onStop() { super.onStop(); Log.d("lifecycle","onStop invoked"); } @Override protected void onRestart() { super.onRestart(); Log.d("lifecycle","onRestart invoked"); } @Override protected void onDestroy() { super.onDestroy(); Log.d("lifecycle","onDestroy invoked"); } }

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download this example

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Output:

You will not see any output on the emulator or device. You need to open logcat.

Now see on the logcat: onCreate, onStart and onResume methods are invoked.