I want to use CoreBluetooth API within iOS keyboard extension (custom keyboard). However, the state for the CBCentralManager is unsupported. The device I use is iPhone 6. It works fine inside the container app. Does this mean that the CoreBluetooth API cannot be used inside the keyboard extension?
You will need to set RequestOpenAccess to YES in your extension's plist under NSExtension > NSExtensionAttributes.
Setting this to YES allows the extension to access network resources. Bluetooth is considered a network resource so you will get CBManagerStateUnsupported when RequestOpenAccess is NO.
来源：https://stackoverflow.com/questions/38546815/ios-corebluetooth-state-unsupported-when-using-in-ios-custom-keyboard