application crashes if it is in idle

i am working on an application.The first screen having login.After launching the application in device and playing with it is all ok and not any issue at all. but if at the same time user opens any other application,uses it for a while and closes this second application and then again navigate to previously open application(on which i am wor开发者_运维百科king),and tries to tap or manipulate or login on the application ,application gets crashed. why so behaviour? i am facing this issue very first time and no any idea of this.

any suggestion?

Thanks.

Check out the Android app lifecycle: http://developer.android.com/reference/android/app/Activity.html.

My guess is the Activity that your user is coming back in to is overriding the onResume() method and the method is throwing an exception or you're not calling super.onResume(). That's my best guess without any more details on what your code is doing or information from your logCat.