RecycleView not visible in PDF (PdfDocument)

Question

I am trying to add RecycleView to PDF document but it's invisible. I tested StatisticsViewHolder and StatisticsAdapter for RecycleView inside Activity and it worked so I am sure that problem lies in setting up RecycleView or pdf_layout.xml.

Moreover I am setting up PDF document correctly since RecycleView is the only element in my pdf_layout.xml which doesn't show up (I removed other elements just for simplicity).

Setting up RecycleView:

PdfDocument document = new PdfDocument();

PdfDocument.PageInfo pageInfo = new PdfDocument.PageInfo.Builder(2250, 1400, 1).create();

PdfDocument.Page page = document.startPage(pageInfo);

LayoutInflater inflater = (LayoutInflater)
        getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View content = inflater.inflate(R.layout.pdf_layout, null);

int measureWidth = View.MeasureSpec.makeMeasureSpec(page.getCanvas().getWidth(), View.MeasureSpec.EXACTLY);
int measuredHeight = View.MeasureSpec.makeMeasureSpec(page.getCanvas().getHeight(), View.MeasureSpec.EXACTLY);

content.measure(measureWidth, measuredHeight);
content.layout(0, 0, page.getCanvas().getWidth(), page.getCanvas().getHeight());

RecyclerView recyclerViewPdf = content.findViewById(R.id.recyclerViewPDF);
recyclerViewPdf.setHasFixedSize(true);
double[] statistics = new double[]{0, 0, 0, 0, 0, 0};
recyclerViewPdf.setLayoutManager(new LinearLayoutManager(getActivity()));
pdfStatisticsAdapter = new StatisticsAdapter(getActivity(), statistics);
recyclerViewPdf.setAdapter(pdfStatisticsAdapter);

content.draw(page.getCanvas());
document.finishPage(page);

pdf_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center">
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerViewPDF"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical" />
</LinearLayout>

I'm not sure if I'm missing something or whether RecycleView cannot be part of pdf_layout in PdfDocument

Answer 1

As it turned out the problem was in setting adapter. I set my adapter outside "main" thread which resulted in following error (I missed that at first glance)

No adapter attached; skipping layout

To solve this problem it is enough to move this part of code:

RecyclerView recyclerViewPdf = content.findViewById(R.id.recyclerViewPDF);
recyclerViewPdf.setHasFixedSize(true);
recyclerViewPdf.setLayoutManager(new LinearLayoutManager(getActivity()));
pdfStatisticsAdapter = new StatisticsAdapter(getActivity(), statistics);
recyclerViewPdf.setAdapter(pdfStatisticsAdapter);

To function called by "main" thread(for example onCreate) or by creating Handler that can be used to post to the main thread.