Question

to know which Apps are installed on a given device i have followed the way as follows.

How to determine, whether an iphone app (previous/next version) is existed in our device or not?

This can find the applications (user’s apps & system apps) installed in SIMULATOR perfectly.

But fail to find in my original device iPod / iPhone.

why and how to rectifie it for Devices?

Answer 1

There’s no way to achieve this on non-jailbroken device.

There is a way (a workaround really) to detect your own applications if they register custom url: method is described here: How To Detect Installed iOS Apps

EDIT: if you decide to go this way you can learn how to register custom URL here:

Registering Custom URL Schemes

Objective-C: Custom URL Schemes

EDIT: after additional information: you want to check if your application is installed and this application registered paintplus URL scheme

You can use this method (in your other application) to check if paintplus is installed or not:

- (BOOL) paintplusInstalledOnThisDevice {

  UIApplication *app = [UIApplication sharedApplication];  
  NSURL *paintplusURL = [NSURL URLWithString: @"paintplus://"];
  return [app canOpenURL: paintplusURL];
}