LinkOS.Plugin.Abstractions.IUsbDiscoverer Interface Reference

Discovers Zebra printers connected to an Android™ device via USB Host More...

Inherited by LinkOS.Plugin.UsbDiscovererImplementation.

Public Member Functions
void	FindPrinters (object androidContext, IDiscoveryHandler handler)
	Initiate discovery Will throw a System.NotImplementedException in iOS More...
bool	IsZebraPrinter (object androidUSBDevice)
	Checks if a USB device is a Zebra printer Will throw a System.NotImplementedException in iOS More...

Detailed Description

Discovers Zebra printers connected to an Android™ device via USB Host

///

Note:Below are 3 methods for doing discovery. They are platform specific. Do not attempt to implement all 3 methods.

using LinkOS.Plugin;
using LinkOS.Plugin.Abstractions;

private void StartUSBDiscovery()
{
    IDiscoveryEventHandler handler = DiscoveryHandlerFactory.Current.GetInstance();
    handler.OnDiscoveryError += DiscoveryHandler_OnDiscoveryError;
    handler.OnDiscoveryFinished += DiscoveryHandler_OnDiscoveryFinished;
    handler.OnFoundPrinter += DiscoveryHandler_OnFoundPrinter;

    // For Android 
    UsbDiscoverer.Current.FindPrinters(Xamarin.Forms.Forms.Context, handler);
    // iOS products are not capable of acting as a USB host.  No implemetation possible.
    throw new NotImplementedException;
    // For Forms apps: implement the previous two methods in OS code projects (PrinterDiscoveryImplementation.cs)
    try
    {
        DependencyService.Get<IPrinterDiscovery>().FindUSBPrinters(handler);
    }
    catch (NotImplementedException)
    {
        System.Diagnostics.Debug.WriteLine("iOS products do not have access to USB peripherals");
    }
}
private void OnFoundPrinter(IDiscoveryHandler handler, IDiscoveredPrinter discoveredPrinter)
{
    Device.BeginInvokeOnMainThread(() => {
        printerList.Add(discoveredPrinter);
    });
}
private void OnDiscoveryError(IDiscoveryHandler handler, string message)
{
    System.Diagnostics.Debug.WriteLine("Discovery Error: " + message);
}
private void OnDiscoveryFinished(IDiscoveryHandler handler, string message)
{
    System.Diagnostics.Debug.WriteLine("Discovery Compete");
}


// Make sure the user has given permission to talk to USB device.
public delegate void GotPrinterHandler(IDiscoveredPrinter discoveredPrinter);
public GotPrinterHandler OnGotPrinter;
private void OnPrinterSelectedFromList(object sender, IDiscoveredPrinter discoveredPrinter)
{
    if (! ((IDiscoveredPrinterUsb)discoveredPrinter).HasPermissionToCommunicate)
    {
        ((IDiscoveredPrinterUsb)discoveredPrinter).RequestPermission(Xamarin.Forms.Forms.Context);
    }
    if (OnGotPrinter != null)
        OnGotPrinter(discoveredPrinter);
}

Member Function Documentation

void LinkOS.Plugin.Abstractions.IUsbDiscoverer.FindPrinters	(	object	androidContext,
		IDiscoveryHandler	handler
	)

Initiate discovery Will throw a System.NotImplementedException in iOS

Parameters

androidContext	The android application context. set to null for iOS
handler	a DiscoveryHandler instance that is used to handle discovery events (e.g. found a printer, errors, discovery finished).

bool LinkOS.Plugin.Abstractions.IUsbDiscoverer.IsZebraPrinter

(

object

androidUSBDevice

)

Checks if a USB device is a Zebra printer Will throw a System.NotImplementedException in iOS

Parameters

androidUSBDevice

a Android.Hardware.Usb.UsbDevice

Returns

true if the USB device is a Zebra device

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The documentation for this interface was generated from the following file:

• C:/repos/xamarin-sdk/Link_OS_SDK_for_Xamarin_Portable/LinkOS/LinkOS.Plugin.Abstractions/IUSBDiscoverer.cs