Android打印使用自定义打印服务

Question

我想写一个自定义的android打印服务。我遵循以下博客中提到的说明： https://github.com/zaki50/MyPrintServiceProject

我能够创建一个服务，它执行打印作业。但是在作业没有打印任何东西之后。我的问题是，我们应该提供什么localId。它是打印机IP，名称？还有什么办法可以知道打印作业不起作用的原因。 基本上这两种方法，我担心正在增加onStartPrinterDiscovery和OnPrintJobQueue如下所述：

@Override 
     public void onStartPrinterDiscovery(List<PrinterId> priorityList) { 
      String str =  Settings.Secure.getString(getBaseContext().getContentResolver(), "enabled_print_services"); 

      Log.d("myprinter", "PrinterDiscoverySession#onStartPrinterDiscovery(priorityList: " + priorityList + ") called") 

      final List<PrinterInfo> printers = new ArrayList<>(); 
      final PrinterId printerId = generatePrinterId("D8:49:2F:64:04:DB"); 
      final PrinterInfo.Builder builder = new PrinterInfo.Builder(printerId, "D8:49:2F:64:04:DB", PrinterInfo.STATUS_IDLE); 
      PrinterCapabilitiesInfo.Builder capBuilder = new PrinterCapabilitiesInfo.Builder(printerId); 
      capBuilder.addMediaSize(PrintAttributes.MediaSize.NA_LETTER, true); 
      capBuilder.addMediaSize(PrintAttributes.MediaSize.NA_LETTER, false); 
      capBuilder.addResolution(new PrintAttributes.Resolution("resolutionId", "default resolution", 600, 600), true); 
      capBuilder.setColorModes(PrintAttributes.COLOR_MODE_COLOR | PrintAttributes.COLOR_MODE_MONOCHROME, PrintAttributes.COLOR_MODE_COLOR); 
      builder.setCapabilities(capBuilder.build()); 
      printers.add(builder.build()); 
      addPrinters(printers); 
     } 

    @Override 
protected void onPrintJobQueued(PrintJob printJob) { 
    Log.d("myprinter", "queued: " + printJob.getId().toString()); 

    printJob.start(); 
    //printJob.complete(); 

    final PrintDocument document = printJob.getDocument(); 

    final FileInputStream in = new FileInputStream(document.getData().getFileDescriptor()); 
    try { 
     final byte[] buffer = new byte[4]; 
     @SuppressWarnings("unused") 
     final int read = in.read(buffer); 
     Log.d("myprinter", "first " + buffer.length + "bytes of content: " + toString(buffer)); 
    } catch (IOException e) { 
     Log.d("myprinter", "", e); 
    } finally { 
     try { 
      in.close(); 
     } catch (IOException e) { 
      assert true; 
     } 
    } 
    if(printJob.isStarted()){ 
     printJob.complete(); 
    } 

} 

我的问题是应该怎样printerId（或LOCALID）。我们如何知道，如果将打印作业成功或失败

Answer 1

你可以做的打印作业状态with other methods in the class检测：

if(printJob.isStarted()){ 

} 
else if(printJob.isCompleted()){ 

} 
else if(printJob.isCancelled()){ 

} 
else if(printJob.isFailed()){ 

} 

此外，打印服务有它自己的方法listed in the docs：

@Override 
protected void onPrintJobQueued(PrintJob printJob) { 
    Log.d("printer", "queued: " + printJob.getId().toString()); 
    printJob.start(); 
    //... 
    printJob.complete(); 
} 

@Override 
protected void onRequestCancelPrintJob(PrintJob printJob) { 
    Log.d("printer", "canceled: " + printJob.getId().toString()); 
    printJob.cancel(); 
}