android application object [closed]

Question

I have read about application object in android site but I couldn't understand.

What is application object android?
What is the use of application object
When we should use application object

Please explain with example.

Thank you.

Answer 1

Application object is an object whose lifecycle is same as our Application.

When Application starts this object is created automatically by Android Framework.

When you want to share data between more than one activities of your application or you want to retain something at application level.In that scenario you can use Application object as a global store for your application.

Example::

// this is your Application Object Class
public class MyApplication extends Application{
}

In your manifest mention it as follows::

<application android:name="yourpkgname.MyApplication"/>

To access application object in any of the activities.Use the following code.

MyApplication app = (MyApplication) getApplication();

I think this is quite enough for you to grab the concept of application object.

Answer 2

q1. What is an Android application Object?

A. According to developer docs Android application object is

"Base class for those who need to maintain global application state. You can provide your own implementation by specifying its name in your AndroidManifest.xml's tag, which will cause that class to be instantiated for you when the process for your application/package is created"

q2. What is the use of Application Object?

A. The Application class is mainly used for some Application level callbacks and for maintaining Global Application state.

So basically here is an implementational idea

public class MyApp extends Application {

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
}

@Override
public void onCreate() {
    super.onCreate();
}

@Override
public void onLowMemory() {
    super.onLowMemory();
}

@Override
public void onTerminate() {
    super.onTerminate();
}

}

q3. When should you use Application Object?

A.When you want to store data, like global variables which need to be accessed from multiple Activities, sometimes everywhere within the application. In this case, the Application object will help you.