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];
}