hi,thank you so much for you info.
i have one kw36 board according to the doc:AN12405.pdf i changed the code as the doc implied. and find one place may be a little puzzled as below redbox encircled.

the mActiveDevices is not declared when i use the redbox code exactly when building, i think it should changed to variable mActiveConnections. i have change it to mActiveConnections,and flashed the project on kw36 freedom board.and used 2 android phone running a BLE scanner.after input the pin it can be connected. press the SW2 button can be connected by another android phone.
it seems work right. please help to verify if mActiveDevices should be altered with mActiveConnections, thanks you still.