java - Android：PDF从webview下载为空

Question

我的应用程序中有一个 webview，用户可以从 html 表单下载不同的 pdf。该文件以正确的名称和格式等下载，但它总是下载空/损坏。我想这可能是一个会话问题，但我不知道。想知道是否有人可以建议。谢谢

public class HomeFragment extends FilePickController {

    private FragmentHomeBinding binding;
    private WebView webView;


    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        HomeViewModel homeViewModel = new ViewModelProvider(this).get(HomeViewModel.class);


        binding = FragmentHomeBinding.inflate(inflater, container, false);
        View root = binding.getRoot();

        webView = (WebView) root.findViewById(R.id.homeWebview);
        webView.setWebChromeClient(new WebChromeClient());
        webView.loadUrl("hidden");

        webView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
                return false;
            }
        });

        webView.setWebChromeClient(returnClient());

        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);

        webView.setDownloadListener(new DownloadListener() {
            @Override
            public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimeType, long contentLength) {
                DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));

                request.setMimeType(mimeType);
                //------------------------COOKIE!!------------------------
                String cookies = CookieManager.getInstance().getCookie(url);
                request.addRequestHeader("cookie", cookies);
                //------------------------COOKIE!!------------------------
                request.addRequestHeader("User-Agent", userAgent);
                request.setDescription("Downloading file...");
                request.setTitle(URLUtil.guessFileName(url, contentDisposition, mimeType));
                request.allowScanningByMediaScanner();
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, URLUtil.guessFileName(url, contentDisposition, mimeType));
                DownloadManager dm =(DownloadManager) getActivity().getSystemService(Context.DOWNLOAD_SERVICE);
                dm.enqueue(request);
                Toast.makeText(getContext(), "Downloading File", Toast.LENGTH_LONG).show();
            }
        });

        return root;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        binding = null;
    }

}

标签： javaandroidwebviewandroid-webview