Class Usb

java.lang.Object
com.codename1.io.usb.Usb
public final class Usb extends java.lang.Object

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.

  • 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 java.io.InputStream openInputStream(UsbDevice device, int endpointAddress) throws java.io.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:
      java.io.IOException

    • openOutputStream

      public static java.io.OutputStream openOutputStream(UsbDevice device, int endpointAddress) throws java.io.IOException
      Throws:
      java.io.IOException