BLE devices not showing up after scanning

Hi all! I'm using app inventor to create a joystick app that will connect to my Arduino R4 WiFi using its the built-in BLE features. I have a button to search for devices, then any devices that are found are added to a listPicker. However, after I press the search button and open up the listPicker, the listPicker is blank. I'm not sure what the problem is here, I'm running the code on a android, so it's not that it doesn't support the BLE extensions.

Here's the code for MIT App Inventor:

Here is the listPicker:

Thank you for the help!