How do i know the ble device is disconnected?

Hi, i'm using ble shield with arduino mega and android app , i need to recognize the ble device disconnection ,how can I get notified ,when the ble device link loss occurs? please help me as soon as possible thanks in advance...

Can you send a message at regular intervals. If the message stops coming you know there is a problem?

…R

how can I get notified ,when the ble device link loss occurs?

How do you know when I have quit reading your posts? Can you reasonably expect the forum to notify you of that?

Not if you are honest with yourself. As Robin2 points out, there must be a steady stream of data, so that you can tell when the stream stops (because too much time has passed since the last data arrived). That means, though, that YOU need to pay attention and notice when the data stopped arriving.