Android webview:像浏览器一样下载文件

我正在开发一款Android应用程序,其webview指向另一个团队的动态网站。
当我下载文件(主要是动态重定向的 PDF和ZIP)时, 我得到的是下载文件夹中的一个文件,其中包含一些HTML代码,其中包含“用户不允许读取文件”等消息 ,无论我如何实现下载,尝试:

  1. 下载管理器
  2. 意图(让外部浏览器管理下载)
  3. “手工”(AsyncTask和httpconnection ……)

都具有相同的结果。

使用普通浏览器进行导航下载工作正常,无论是在台式PC,Android还是iOS设备上

为什么webview不能访问文件?

可能会议问题? http端口?
我真的需要一些想法……

另一个提示:当从同一个链接下载两次文件时,该链接将重定向到同一个文件,但会产生两个不同的文件名…

编辑 :我没有将webView指向网络应用程序,而是试图指向一个带链接重定向的常见网页来下载另一个文件,好吧,简单地说就可以了。

以下是webview.setDownloadListener - onDownloadStart()参数:

  userAgent=Mozilla/5.0 (Linux; Android 4.4.2; Nexus 7 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/30.0.0.0 Safari/537.36 contentDisposition=attachment; filename=correct_filename.pdf, url=http://www.xxx.xx/site/downloadfile.wplus?REDIRECTFILE=D-507497120&ID_COUNTOBJ=ce_5_home&TYPEOBJ=CExFILE&LN=2 mimeType=application/octet-stream 

这是一些代码

  wv.getSettings().setSupportMultipleWindows(true); wv.getSettings().setJavaScriptCanOpenWindowsAutomatically(true); wv.getSettings().setAllowFileAccess(true); wv.getSettings().setJavaScriptEnabled(true); wv.getSettings().setBuiltInZoomControls(true); wv.getSettings().setDisplayZoomControls(false); wv.getSettings().setLoadWithOverviewMode(true); wv.getSettings().setUseWideViewPort(true); wv.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.setDescription("Download file..."); request.setTitle(URLUtil.guessFileName(url, contentDisposition, mimetype)); request.allowScanningByMediaScanner(); request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED); //Notify client once download is completed! request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, URLUtil.guessFileName(url, contentDisposition, mimetype)); DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE); dm.enqueue(request); Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_LONG).show(); } } 

编辑二

这是我在尝试“手动”下载文件时使用的代码:

onDownloadStart()是我调用downloadFileAsync()的地方:

  public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimeType, long contentLength) { String fileName; try { fileName = URLUtil.guessFileName(url, contentDisposition, mimeType); downloadFileAsync(url, fileName); }catch (Exception e){ } } 

这是AsyncTask:

 private void downloadFileAsync(String url, String filename){ new AsyncTask() { String SDCard; @Override protected void onPreExecute() { super.onPreExecute(); } @Override protected String doInBackground(String... params) { try { URL url = new URL(params[0]); HttpURLConnection urlConnection = null; urlConnection = (HttpURLConnection) url.openConnection(); urlConnection.setRequestMethod("GET"); urlConnection.setDoOutput(true); urlConnection.connect(); int lengthOfFile = urlConnection.getContentLength(); //SDCard = Environment.getExternalStorageDirectory() + File.separator + "downloads"; SDCard = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)+""; int k = 0; boolean file_exists; String finalValue = params[1]; do { if (k > 0) { if (params[1].length() > 0) { String s = params[1].substring(0, params[1].lastIndexOf(".")); String extension = params[1].replace(s, ""); finalValue = s + "(" + k + ")" + extension; } else { String fileName = params[0].substring(params[0].lastIndexOf('/') + 1); String s = fileName.substring(0, fileName.lastIndexOf(".")); String extension = fileName.replace(s, ""); finalValue = s + "(" + k + ")" + extension; } } File fileIn = new File(SDCard, finalValue); file_exists = fileIn.exists(); k++; } while (file_exists); File file = new File(SDCard, finalValue); FileOutputStream fileOutput = null; fileOutput = new FileOutputStream(file, true); InputStream inputStream = null; inputStream = urlConnection.getInputStream(); byte[] buffer = new byte[1024]; int count; long total = 0; while ((count = inputStream.read(buffer)) != -1) { total += count; //publishProgress(""+(int)((total*100)/lengthOfFile)); fileOutput.write(buffer, 0, count); } fileOutput.flush(); fileOutput.close(); inputStream.close(); } catch (MalformedURLException e){ } catch (ProtocolException e){ } catch (FileNotFoundException e){ } catch (IOException e){ } catch (Exception e){ } return params[1]; } @Override protected void onPostExecute(final String result) { } }.execute(url, filename); } 

摘自如何从Webview中的动态URL下载PDF
感谢名单

最后,我决定从Android Stock Browser代码中查找DownloadHandler 。 我的代码唯一明显的缺点是cookie (!!!)。

这是我的最终工作版本(DownloadManager方法):

  wv.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) getSystemService(DOWNLOAD_SERVICE); dm.enqueue(request); Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_LONG).show(); } }); 
 wv.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) getSystemService(DOWNLOAD_SERVICE); dm.enqueue(request); Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_LONG).show(); } }); 

谢谢你错过了你的答案); 在代码结束..

AsyncTask手动检索文件名(您可以向此类添加其他代码):

 private static class getFileNameAsync extends AsyncTask { @Override protected void onPreExecute() { super.onPreExecute(); } @Override protected String doInBackground(String... params) { URL url; String filename = null; HttpURLConnection conn = null; try { url = new URL(params[0]); conn = (HttpURLConnection) url.openConnection(); conn.connect(); conn.setInstanceFollowRedirects(false); try { for(int i = 0; i < 100; i++) { String stringURL = conn.getHeaderField("Location"); if (stringURL != null) { url = new URL(stringURL); conn = (HttpURLConnection) url.openConnection(); conn.connect(); conn.setInstanceFollowRedirects(false); } else { i = 100; } } } catch (Exception e) { e.printStackTrace(); } String depo = conn.getHeaderField("Content-Disposition"); if (depo != null) { String depoSplit[] = depo.split(";"); int size = depoSplit.length; for(int i = 0; i < size; i++) { if(depoSplit[i].startsWith("filename=")) { filename = depoSplit[i].replaceFirst("(?i)^.*filename=\"?([^\"]+)\"?.*$", "$1").trim(); i = size; } } } } catch (MalformedURLException e){ e.printStackTrace(); } catch (ProtocolException e){ e.printStackTrace(); } catch (FileNotFoundException e){ e.printStackTrace(); } catch (IOException e){ e.printStackTrace(); } catch (Exception e){ e.printStackTrace(); } finally { if (conn != null) conn.disconnect(); } return filename; } @Override protected void onPostExecute(String filename) { super.onPostExecute(filename); } } 

DownloadListener(它的稳定版本,不要更改它):

  mWebView.setDownloadListener(new DownloadListener() { @Override public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) { if(Build.VERSION.SDK_INT >=23){ Context nContext = MainActivity.this.getApplicationContext(); if(nContext.checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){ MainActivity.this.requestPermissions(new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1); return; } } String fileName = ""; url = url.replace(" ", "%20"); AsyncTask asyncTask = new getFileNameAsync(); asyncTask.execute(url); try { fileName = asyncTask.get(); } catch (InterruptedException e) { e.printStackTrace(); } catch (ExecutionException e) { e.printStackTrace(); } catch (CancellationException e) { e.printStackTrace(); } if ((fileName == null) || (fileName.hashCode() == "".hashCode())) { fileName = URLUtil.guessFileName(url, contentDisposition, mimetype); } DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url)); request.setMimeType(mimetype); String cookies = CookieManager.getInstance().getCookie(url); request.addRequestHeader("Cookie", cookies); request.addRequestHeader("User-Agent", userAgent); request.setDescription("Downloading File"); request.setTitle(fileName); request.allowScanningByMediaScanner(); request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED); request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName); DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE); if (downloadManager != null) { downloadManager.enqueue(request); } Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_LONG).show(); } });