Global Variable in Android

Introduction

When we need to have several variables across applications, we can go for global variable. Here, I am going to explain, defining global variable by extending the Android's Application class. This is the base class for maintaining global application state.

Steps for Declaring Global Variable

1. Create a class that extends the Application class:
   Java

   public  class  Global extends Application {
       private Boolean _notification=false;
       public Boolean get_notification() {
           return _notification;
       }
       public void set_notification(Boolean _notification) {
           this._notification = _notification;
       }
   } 

2. Add the class to the AndroidManifest file as an attribute of <application> tag:
   Java

    <application
   android:name=".Global"
           .... />  

3. You can access it from any context using the Context.getApplicationContext() method. Now, we can access the global data across the application like:
   Java

   Global global;
      public void onCreate(Bundle savedInstanceState) {
          global=((Global)getApplicationContext());
          Boolean notification=global.get_notification();}
   

History

• 26^th June, 2013: Initial post

This tip is based on the following blog:

• http://articlesforprogramming.blogspot.in