Can pdfrx be displayed as a single page by default?

[zengchanghuan]

Because the number of pages in the PDF file may be large, I want to display only 1 page at a time, how do I set it?

[espresso3389]

You can do that by using PdfViewerParams.layoutPages.

By the way,

Because the number of pages in the PDF file may be large, ...

It does not reduce the total memory consumption by restricting the viewer to show only one page. It at most caches only three pages. And, furthermore, all the PDF data is anyway loaded on the memory.

For the cache control, PdfViewerParams.maxImageBytesCachedOnMemory may help you.

[zengchanghuan]

            PdfViewer.asset(
              'assets/sample.pdf',
              passwordProvider: () => passwordDialog(context),
              controller: controller,
              params: PdfViewerParams(
                maxImageBytesCachedOnMemory: 50 * 1024 * 1024,
                enableTextSelection: true,
                maxScale: 8,
                // facing pages algoritm
                layoutPages: (pages, params) {
                  // They should be moved outside function
                  const isRightToLeftReadingOrder = false;
                  const needCoverPage = true;
                  final width = pages.fold(
                      0.0, (prev, page) => max(prev, page.width));

                  final pageLayouts = <Rect>[];
                  double y = params.margin;
                  for (int i = 0; i < pages.length; i++) {
                    const offset = needCoverPage ? 1 : 0;
                    final page = pages[i];
                    final pos = i + offset;
                    final isLeft = isRightToLeftReadingOrder
                        ? (pos & 1) == 1
                        : (pos & 1) == 0;

                    final otherSide = (pos ^ 1) - offset;
                    final h = 0 <= otherSide && otherSide < pages.length
                        ? max(page.height, pages[otherSide].height)
                        : page.height;

                    pageLayouts.add(
                      Rect.fromLTWH(
                        isLeft
                            ? width + params.margin - page.width
                            : params.margin * 2 + width,
                        y + (h - page.height) / 2,
                        page.width,
                        page.height,
                      ),
                    );
                    if (pos & 1 == 1 || i + 1 == pages.length) {
                      y += h + params.margin;
                    }
                  }
                  return PdfPageLayout(
                    pageLayouts: pageLayouts,
                    documentSize: Size(
                      (params.margin + width) * 2 + params.margin,
                      y,
                    ),
                  );
                },
                //
                // Scroll-thumbs example
                //
                viewerOverlayBuilder: (context, size) => [
                  // Show vertical scroll thumb on the right; it has page number on it
                  PdfViewerScrollThumb(
                    controller: controller,
                    orientation: ScrollbarOrientation.right,
                    thumbSize: const Size(40, 25),
                    thumbBuilder:
                        (context, thumbSize, pageNumber, controller) =>
                            Container(
                      color: Colors.black,
                      child: Center(
                        child: Text(
                          pageNumber.toString(),
                          style: const TextStyle(color: Colors.white),
                        ),
                      ),
                    ),
                  ),
                  // Just a simple horizontal scroll thumb on the bottom
                  PdfViewerScrollThumb(
                    controller: controller,
                    orientation: ScrollbarOrientation.bottom,
                    thumbSize: const Size(80, 30),
                    thumbBuilder:
                        (context, thumbSize, pageNumber, controller) =>
                            Container(
                      color: Colors.red,
                    ),
                  ),
                ],
                //
                // Loading progress indicator example
                //
                loadingBannerBuilder:
                    (context, bytesDownloaded, totalBytes) => Center(
                  child: CircularProgressIndicator(
                    value: totalBytes != null
                        ? bytesDownloaded / totalBytes
                        : null,
                    backgroundColor: Colors.grey,
                  ),
                ),
                //
                // Link handling example
                //
                // FIXME: a link with several areas (link that contains line-break) does not correctly
                // show the hover status
                linkWidgetBuilder: (context, link, size) => Material(
                  color: Colors.blue.withOpacity(0.2),
                  child: InkWell(
                    onTap: () async {
                      if (link.url != null) {
                        navigateToUrl(link.url!);
                      } else if (link.dest != null) {
                        controller.goToDest(link.dest);
                      }
                    },
                    hoverColor: Colors.blue.withOpacity(0.2),
                  ),
                ),
                pagePaintCallbacks: [
                  textSearcher.pageTextMatchPaintCallback,
                  _paintMarkers,
                ],
                onDocumentChanged: (document) async {
                  if (document == null) {
                    documentRef.value = null;
                    outline.value = null;
                    _selectedText = null;
                    _markers.clear();
                  }
                },
                onViewerReady: (document, controller) async {
                  documentRef.value = controller.documentRef;
                  outline.value = await document.loadOutline();
                },
                onTextSelectionChange: (selection) {
                  _selectedText = selection;
                },
              ),

Because the file size is too large and causes carsh, I want to display only 1 page at a time, and then slide to turn the page. But the above code doesn't do the trick, please how do I need to do it, thanks! The sample.pdf is ：https://files.acadsoc.com.cn/uploads/subdocument/official/20210202/b70a167f-66e3-4f47-a562-5696b563b925.pdf

[bailyzheng]

I need this feature too. It should auto play page by page on some display devices that not for interative.