问题
I have 2 Android devices, which I would like to connect with a USB OTG cable and have back-and-forth communication between the two devices. From what I understand, one Android device will act as the USB Host (Nexus 7 running 4.4) and the other Android device will act as a USB Accessory (Galaxy Nexus running 4.2.2). I've tried googling around for an answer, but I can only seem to find articles explaining how to connect an Android device to a USB accessory (like a USB mouse or keyboard), not how to treat an Android device as the USB accessory itself.
So, following this page, I have configured an app on the Nexus 7 to be the USB Host. I can find the connected Galaxy Nexus based on its product id & vendor id, form a connection to the Android Open Accessory Protocol and successfully connect over USB. From what I can tell, the Nexus 7 can successfully send bytes to the Galaxy Nexus.
My question is how to access this connection on the Galaxy Nexus side. I have added permissions and the USB filter into the manifest, so the desired app opens on the Galaxy Nexus once the USB connection is established, but I can't figure out how to receive the data coming in from the Nexus 7 or how to send data from the Galaxy Nexus back to the Nexus 7.
Any help would be greatly appreciated! Thanks!
回答1:
See my SO answer here.
If you want the Galaxy Nexus to act as the USB Accessory, then it must implement the Android Open Accessory protocol. An Android Accessory is a usb host, so technically you would have two hosts (assuming you managed to implement correctly the AOA protocol on the Galaxy Nexus), which is clearly a deviation of the USB spec.
来源：https://stackoverflow.com/questions/20226272/android-device-acting-as-an-accessory