If i am playing a game like candy crush and there is a incoming call then the game restarts. Or if i am broadcasting a message on Whatsapp then the list gets to zero after the incoming call. Why please help
Unfornately, this is how those apps handle themselves when being put to sleep (in the background) while you attend to another app. Some apps will freeze their state, others will save their state in internal memory and exit to save RAM for your phone while you use some other app; it will load its state again once you go back in.