In my application , i works with web-services and when user log in into my app my app is sending a request with status 1 means loged in and when on log out button click sending
It is not possible to call a web service when the user deleting the app from an ios device. There are three methods to came to know that whether your application is there in user's ios device. But there are few limitations also.
Activate Push notification: By doing this, device will get registered with Apple's push notification service. When user delete the app from device, the registration will be revoked from APNS server and through the APNS feedback service, you can get to know whether the application is existing. (Limitation: If the user did not agree with receiving push notifications, then the app will not be registered with APNS and you never came to know that whether application is existing or not)
Activate Location Based service: If your application enables location based service, then your application will get periodic location updates in a location delegate method. In this delegate, you can call a webservice and keep update the status of user even the application is in background. (Limitation: If user disables the location update, then your server will not get info about user status)
Periodically Call a Webservice From you app: This is possible only if your app is active. (Limitation: When you application pushed in to background, your application will be in suspended mode, so it will not possible to call webservice)