从Flutter资产加载.pdf文件/自定义文件

将资产复制到一个临时文件。

  Future<File> copyAsset() async {    Directory tempDir = await getTemporaryDirectory();    String tempPath = tempDir.path;    File tempFile = File('$tempPath/copy.pdf');    ByteData bd = await rootBundle.load('assets/asset.pdf');    await tempFile.writeAsBytes(bd.buffer.asUint8List(), flush: true);    return tempFile;  }