If you have a real device then use it instead. The emulator is slow and unreliable. You can connect to it with B4A-Bridge or USB debug mode.
I have Nexus 7 Wifi, but also have another problems.
Here are the problems :
1) when ping nexus 7 ip address, always got request time out, but B4A-Bridge on Nexus 7, shows Status connected, also on Basic4Andorid status bar, it is written B4ABridge - Connected
2) when open designer, I got status disconnected, and when double clicked Connection Icon, Nexus 7 screen shows B4A Designer, but Designer IDE still shows disconnected
So, AVD and B4A-Bridge are not working.