java - 如何判断打印作业是否完成？

Question

在我的 Android 应用程序中，我正在尝试打印 PDF 文档，一切正常，这是我当前用于打印文件的代码段

private void printFile(){
        PrintManager printManager = (PrintManager) this.getSystemService(getApplicationContext().PRINT_SERVICE);
        PrintDocumentAdapter pda = new PrintDocumentAdapter(){

            @Override
            public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback){
                OutputStream output = null;

                try {
                    output = new FileOutputStream(destination.getFileDescriptor());
                    byte[] buf = _responseBody;
                    output.write(buf);
                    callback.onWriteFinished(new PageRange[]{PageRange.ALL_PAGES});

                } catch (FileNotFoundException ee){
                    //Catch exception
                } catch (Exception e) {
                    //Catch exception
                } finally {
                    try {
                        output.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }

            @Override
            public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras){
                if (cancellationSignal.isCanceled()) {
                    callback.onLayoutCancelled();
                    return;
                }

                PrintDocumentInfo pdi = new PrintDocumentInfo.Builder("Name of file").setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).build();
                callback.onLayoutFinished(pdi, true);
            }

            @Override
            public void onFinish(){
                System.out.println("PRINT IS FINISHED");
            }
        };



        PrintAttributes printAttrs = new PrintAttributes.Builder().
                setMediaSize(PrintAttributes.MediaSize.ISO_A6).
                setMinMargins(PrintAttributes.Margins.NO_MARGINS).
                build();

        PrintJob printJob = printManager.print(labelID, pda, printAttrs);

    }

但是，当打印完成后，我想运行一个方法来返回到应用程序的先前 View ，因此我需要捕获打印作业完成时触发的事件，有人可以解释一下如何执行此操作吗？任何代码 fragment 将不胜感激。

Answer 1

我同意 CommonsWare 的评论，打印作业可能需要很长时间，并且在某些情况下可能会无限期地处于“阻止”状态。根据记录，onFinish()回调应该在正常打印成功的情况下工作。