Question

在我的Android打印类中，有时我会在onWrite函数中遇到PageRange的参数为null，它是一个覆盖函数，并且值是从Android框架传递的，我想找到它为什么有时为空的原因（不是100％）？这是设备问题吗？有没有人见过这个？代码和日志如下：

class PdfFragmentPrintDocumentAdapter extends PrintDocumentAdapter{
  public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback) {

    ........
    callback.onWriteFinished(pages);
  }
 .........


java.lang.IllegalArgumentException: pages cannot be empty
     at android.print.PrintManager$PrintDocumentAdapterDelegate$MyWriteResultCallback.onWriteFinished(PrintManager.java:961)
     at com.microsoft.pdfviewer.PdfFragmentPrint$PdfFragmentPrintDocumentAdapter$2.run(PdfFragmentPrint.java:265)
     at com.microsoft.pdfviewer.PdfFragmentPrint$PdfFragmentPrintDocumentAdapter.implementOnWriteInDedicatedThread(PdfFragmentPrint.java:278)
     at com.microsoft.pdfviewer.PdfFragmentPrint$PdfFragmentPrintDocumentAdapter.onWrite(PdfFragmentPrint.java:213)
     at android.print.PrintManager$PrintDocumentAdapterDelegate$MyHandler.handleMessage(PrintManager.java:792)

Answer 1

除非您明确提取页面，否则请调用onWriteFinished(new PageRange[]{PageRange.ALL_PAGES})并编写整个pdf。在这种情况下，即使传递了页面范围，系统也会渲染并仅打印所选页面。

Android PrintManager PageRange为null

1 个答案: