FutureBuilder
body: FutureBuilder( future: PDFDocument.openAsset('assets/button.pdf'), builder: (context, AsyncSnapshot<PDFDocument> snapshot) { if (!snapshot.hasData || snapshot.hasError) { FutureBuilderはAPI呼び出しとかにいいと思う</pdfdocument>
body: FutureBuilder( future: PDFDocument.openAsset('assets/button.pdf'), builder: (context, AsyncSnapshot<PDFDocument> snapshot) { if (!snapshot.hasData || snapshot.hasError) { FutureBuilderはAPI呼び出しとかにいいと思う</pdfdocument>