LDKPrinter

/*!
 * @discussion Simple description of the current printer class
 */
- (NSString*) aboutDescription;

/*!
 * @discussion Determines whether printer supports printing images
 * @return TRUE if the printer supports printing images, FALSE otherwise
 */
- (BOOL) supportsImages;

/*!
 * @discussion Initialization method for external printer, requires serial number
 * @warning This method must be called before anything can be done to the printer object
 * @param serialNumber The serial number of the external device
 */
-(void) bindToPrinterWithSerialNumber:(NSString*) serialNumber;

/*!
 * @discussion Closes the connection the printer
 * @warning This method should be called after printing to prevent memory leaks
 */
-(void) unbind;

/*!
 * @discussion Standardized method for all implementing classes to update delegate
 * @param printerStatus An LDKPrinterStatus indicating current status of printer
 * @param message The string representing the printer status
 */
-(void) updatePrinterStatus:(LDKPrinterStatus) status withMessage:(NSString*) message;

/*!
 * @discussion Asynchronous method for printing an LDMItem
 * @param item The LDMItem to print (expected to be a Cart with line items)
 * @param config The PrintConfig item
 * @param completion Asychronous block that is called after receipt finishes printing
 */
-(void) printReceiptForItem:(LDMItem*) item withConfig:(LDKPrinterConfig*) config andCompletionHandler: (void (^)(BOOL success, NSString* message)) completion;

Writing Your Own Printer Manager

Liquid Core API comes with LDKPrinterManagerViewController to easily select existing printers and print carts. However, if there is a desire to write your own, this can be done some guidelines.

• Use LDKPrinterFactory to retrieve the correct LDKPrinter implementation
• Implement the printer delegate
  • This is used to update UI Labels to check printer status
  • Bind the printer

self.printer = [LDKPrinterFactory printerForProfile:self.printerProfile];
self.printer.delegate = self;
[self.printer bindToPrinterWithSerialNumber:self.defaultPrinterSerialNumber];

After the printing has been binded, you can proceed to print the item of interest:

[self.printer printReceiptForItem:self.cart withConfig:config andCompletionHandler:^(BOOL success, NSString *message) {
        [self enableDoneButton];
        if (!success)
        {
            [[[UIAlertView alloc] initWithTitle:@"Alert" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
        }
    }];

The following code is an easy way to obtain all external accessories connected to the current iOS device:

EAAccessoryManager *manager = [EAAccessoryManager sharedAccessoryManager];
self.connectedDevices = [NSMutableArray arrayWithArray:manager.connectedAccessories];

Remember to call unbind when printing has completed, or else memory leaks may occur.

[self.printer unbind];

The actual printing code is executed on a priority queue, defined below:

dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

The completion handler is called by the main thread when it is done, so there is never any need to dispatch a new thread to update the UI.