Bluetooth Connectivity Problem

I created an app with bluetooth connectivity. And I’m using Arduino + HC-05 with this App. But my problem is that my bluetooth module stays connected with the app only for few seconds and then disconnects. I checked the bluetooth module and it is ok. What could be the problem? I am very sad. Please, help me.
i have provided the screenshot of the block code of bluetooth connectivity.

check logcat

Taifun