打开使用下载管理器下载的文件 Android答案

【问题标题】：Open a file downloaded using download manager Android打开使用下载管理器下载的文件 Android
【发布时间】：2018-11-11 08:17:13
【问题描述】：

我已使用此代码在我的应用程序中下载 pdf 文件，它适用于所有手机，但我编写的用于打开下载文件的代码适用于小于 21 的 APK，但不适用于更好的手机，例如三星S7等

我下载pdf文件的代码：

Boolean memoerAvailable = (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED));
if (memoerAvailable) {
  final DownloadManager.Request request = new DownloadManager.Request(Uri.parse(link));
  request.setTitle("Click to download the book");
  request.setDescription("File is being downloaded...");

  //use download manager to download the clicked book
  request.allowScanningByMediaScanner();
  request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
  request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, ShowbooksActivity.myBooksList.get(ShowbooksActivity.pos).getMpdfName());
  request.setDestinationInExternalFilesDir(bookWithAdapterActivity.this, Environment.DIRECTORY_DOWNLOADS, "myfile.jpg");
  final DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
  final long queueid = manager.enqueue(request);

我打开下载文件的代码：

filetoopen = ls1.get(position);
File file = new File(Environment.getExternalStorageDirectory() +"/Download/" + filetoopen);
intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(file), "application/pdf");
intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
try {
  startActivity(intent);
} catch (ActivityNotFoundException e) {
  Toast.makeText(getContext(), "File not found", Toast.LENGTH_SHORT).show();

}

【问题讨论】：

您遇到什么错误？有错误信息吗？

标签： android android-studio

【解决方案1】：

你有例外吗？尝试使用 FileProvier for API>23.

Open downloaded file on Android N using FileProvider

【讨论】：

每当我尝试打开任何已下载的图书时，应用程序都会崩溃
因为 API>23 你必须使用 FileProvider

【解决方案2】：

试试这个

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);
            String cookies = CookieManager.getInstance().getCookie(url);
            request.addRequestHeader("cookie", cookies);
            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();
        }
    });

【讨论】：