HOW TO KNOW APPLICATION ALREADY INSTALLED OR NOT ?

Code snippets :

public static boolean isPackageInstalled(String packagename, Context context)

{

try 

{

PackageManager pm = context.getPackageManager();

/*

* PackageManager.GET_ACTIVITIES

* PackageInfo flag: return information about activities in the package in activities.

*/

PackageInfo packageInfo =

                                       pm.getPackageInfo(packagename, PackageManager.GET_ACTIVITIES);

if(packageInfo != null)

return true;

else

return false;

} 

        catch (NameNotFoundException e) 

{

return false;

}

}