public final class Usb

Object
Usb

USB Host API.

Lets the device act as a USB host and talk to attached peripherals – a barcode scanner, a serial-over-USB device, a microcontroller. This is Android-only in practice; iOS doesn’t expose third-party USB host access and the simulator/JavaSE port stubs everything out.

Android specifics

The build pipeline adds the android.hardware.usb.host feature and a <uses-feature> declaration whenever Usb is referenced. To launch your app automatically when a device is plugged in, declare a USB_DEVICE_ATTACHED intent filter in android.xintent_filter using a device_filter.xml resource you ship in native/android/res/xml/. See Developer Guide -> Network Connectivity -> USB.

Methods

`public static boolean isSupported()`	`true` if the current platform implements USB host access.
`public static` `UsbDevice[] listDevices()`	All currently-attached USB devices.
`public static void addDeviceListener(UsbDeviceListener listener)`	Subscribes `listener` to attach / detach events.
`public static void removeDeviceListener(UsbDeviceListener listener)`
`public static void requestPermission(UsbDevice device)`	Requests permission from the user to talk to `device`.
`public static boolean hasPermission(UsbDevice device)`	`true` if the user has granted access to `device`.
`public static` `InputStream openInputStream(UsbDevice device, int endpointAddress) throws IOException`	Opens a bulk-transfer endpoint on the device.
`public static` `OutputStream openOutputStream(UsbDevice device, int endpointAddress) throws IOException`

Inherited methods

From Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait, clone

Method details

isSupported

public static boolean isSupported()

true if the current platform implements USB host access.

listDevices

public static UsbDevice[] listDevices()

All currently-attached USB devices.

addDeviceListener

public static void addDeviceListener(UsbDeviceListener listener)

Subscribes listener to attach / detach events. Returns immediately. Calls on the EDT.

removeDeviceListener

public static void removeDeviceListener(UsbDeviceListener listener)

requestPermission

public static void requestPermission(UsbDevice device)

Requests permission from the user to talk to device. The result is reported asynchronously via UsbDeviceListener.onPermissionResult.

hasPermission

public static boolean hasPermission(UsbDevice device)

true if the user has granted access to device.

openInputStream

public static InputStream openInputStream(UsbDevice device, int endpointAddress)
throws IOException

Opens a bulk-transfer endpoint on the device. endpointAddress matches the USB endpoint address from the device’s descriptor. The caller must have called requestPermission and received approval first.

Throws

IOException

openOutputStream

public static OutputStream openOutputStream(UsbDevice device, int endpointAddress)
throws IOException

Throws

IOException