PrintShopPrintDocumentAdapter.java 文件源码

@Override
public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, final WriteResultCallback callback) {

    // Register a cancellation listener
    cancellationSignal.setOnCancelListener(new CancellationSignal.OnCancelListener() {
        @Override
        public void onCancel() {
            // If cancelled then ensure that the PDF doc gets thrown away
            pdfDocument.close();
            pdfDocument = null;
            // And callback
            callback.onWriteCancelled();
        }
    });

    // Iterate through the pages
    for (int currentPageNumber = 0; currentPageNumber < pageCount; currentPageNumber++) {
        // Has this page been requested?
        if(!pageRangesContainPage(currentPageNumber, pages)) {
            // Skip this page
            continue;
        }

        // Start the current page
        PdfDocument.Page page = pdfDocument.startPage(currentPageNumber);

        // Get the canvas for this page
        Canvas canvas = page.getCanvas();

        // Draw on the page
        drawPage(currentPageNumber, canvas);

        // Finish the page
        pdfDocument.finishPage(page);
    }

    // Attempt to send the completed doc out
    try {
        pdfDocument.writeTo(new FileOutputStream(destination.getFileDescriptor()));
    } catch (IOException e) {
        callback.onWriteFailed(e.toString());
        return;
    } finally {
        pdfDocument.close();
        pdfDocument = null;
    }

    // The print is complete
    callback.onWriteFinished(pages);
}