Summary android application buliding:Activities

The paused activity does not receive user input and cannot execute any code and called when
onPause()
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.

Example
This example will take you through simple steps to show Android application activity life cycle. Follow the following
steps to modify the Android application we created in Hello World Example chapter:

Step Description

You will use Eclipse IDE to create an Android application and name it as HelloWorld under a
1
package com.example.helloworld as explained in the Hello World Example chapter.

2 Modify main activity file MainActivity.java as explained below. Keep rest of the files unchanged.

3 Run the application to launch Android emulator and verify the result of the changes done in the aplication.

Following is the content of the modified main activity filesrc/com.example.helloworld/MainActivity.java. This file
includes each of the fundamental lifecycle methods. The Log.d() method has been used to generate log
messages:

package com.example.helloworld;

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

public class MainActivity extends Activity {
String msg = "Android : ";

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(msg, "The onCreate() event");
}

/** Called when the activity is about to become visible. */
@Override
protected void onStart() {
super.onStart();
Log.d(msg, "The onStart() event");
}

/** Called when the activity has become visible. */
@Override
protected void onResume() {
super.onResume();
Log.d(msg, "The onResume() event");
}

/** Called when another activity is taking focus. */
@Override


TUTORIALS POINT
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