UIPrintErrorDomain error 4 on printing with UISimpleTextPrintFormatter

问题

I have the following codes to print a simple text. I'm using HP Officejet 4630 series. But I'm getting UIPrintErrorDomain error 4 as well as error 3.

Any idea why?

UIPrintInfo *pi = [UIPrintInfo printInfo];
pi.outputType = UIPrintInfoOutputGeneral;
pi.jobName = @"test";

UIPrintInteractionController *pic = [UIPrintInteractionController sharedPrintController];
pic.printInfo = pi;

UISimpleTextPrintFormatter *formatter = [[UISimpleTextPrintFormatter alloc] initWithText:@"testing 123"];
formatter.contentInsets = UIEdgeInsetsMake(72, 72, 72, 72);
pic.printFormatter = formatter;

NSString *url = [[NSUserDefaults standardUserDefaults] objectForKey:@"printer"];
UIPrinter *printer = [UIPrinter printerWithURL:[NSURL URLWithString:url]];

[pic printToPrinter:printer completionHandler:^(UIPrintInteractionController * __nonnull printInteractionController, BOOL completed, NSError * __nullable error) {
    NSLog(@"error -> %@", error);
}];

I have correct printer URL. I'm getting the following error.

ipp://HPD0...15287.local.:631/ipp/print: startJob: Unable to connect to printd: Bad file descriptor

Error Domain=UIPrintErrorDomain Code=4 "The operation couldn’t be completed. (UIPrintErrorDomain error 4.)"

回答1:

Also lost some time seeking for solution. Found such one:

First - choose printer for the first time (Just as it was before ios 13) and save its printer NSURL.

  private selectPrinter() {
    const printPicker = UIPrinterPickerController.printerPickerControllerWithInitiallySelectedPrinter(null);
    const view = utils.ios
      .getter(UIApplication, UIApplication.sharedApplication).keyWindow.rootViewController.view;
    const theFrame = frame.topmost().currentPage.frame;

    printPicker.presentFromRectInViewAnimatedCompletionHandler(
      theFrame, view, true, (printerPicker, userDidSelect, error) => {
        if (userDidSelect) {
          this.someService.printerUrl = printerPicker.selectedPrinter.URL;
        } else {
          setTimeout(() => { this.selectPrinter(); }, 4);
        }
      },
    );
  }

Then use printer by its NSURL without a necessity to choose printer each time Special thanks to @moeseth for idea.

    const printer = UIPrinter.printerWithURL(this.someService.printerUrl);

    printer.contactPrinter((available) => {
      if (available) {
        controller.printToPrinterCompletionHandler(printer, callback);
      } else {
        alert("Printer Not Found");
      }
    });

Hope it will help someone

来源：https://stackoverflow.com/questions/31289969/uiprinterrordomain-error-4-on-printing-with-uisimpletextprintformatter

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ios

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