当我通过intent打开PDF时，无法在Android中显示PDF（无法打开）

我通过url下载PDF，保存后通过intent打开。但是它说不能显示PDF（不能打开）。我还授予了所有的读写权限。PDF已成功保存，我还可以在我的文件管理器中查看，并可以从那里打开它。但不是从我的应用程序

已用代码=>

  private void downloadAndViewAttachment(String url) {

    String extension = url.substring(url.lastIndexOf("."));
    Log.v("extension", extension);

    fileName = url.substring(url.lastIndexOf("/"));
    fileName = fileName.replace("/", "");
    Log.v("fileName", fileName);
    final File file = new File(Environment.getExternalStoragePublicDirectory(getString(R.string.app_name)),   AppConstants.Attachments);

    AndroidNetworking.download(url, file.getPath(), AppUtils.getTimeStamp() + "_" + fileName)
            .setPriority(Priority.HIGH)
            .build()
            .setDownloadProgressListener(new DownloadProgressListener() {
                @Override
                public void onProgress(long bytesDownloaded, long totalBytes) {

                    AppUtils.showRequestDialog(mActivity);

                }
            })
            .startDownload(new DownloadListener() {
                @Override
                public void onDownloadComplete() {

                    AppUtils.hideDialog(mActivity);
                    AppUtils.showToastSort(mActivity, getString(R.string.download_succesfully));
                    openPdfFile(file.getPath() + "/" + AppUtils.getTimeStamp() + "_" + fileName);
                  

                }

                @Override
                public void onError(ANError anError) {

                    AppUtils.hideDialog(mActivity);
                    Log.v("downloadError", anError.getErrorBody());
                    Log.v("downloadError", anError.getErrorDetail());
                    Log.v("downloadError", String.valueOf(anError.getErrorCode()));
                    AppUtils.showToastSort(mActivity, getString(R.string.something_error));

                }
            });

}

private void openPdfFile(String path) {

    AppUtils.hideDialog(mActivity);

    File file = new File(path);
    Intent intent = new Intent(Intent.ACTION_VIEW);
    intent.setDataAndType(Uri.fromFile(file), "application/pdf");
    intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
    intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    startActivity(intent);

}

---

如果函数

AppUtils.getTimeStamp（）

确实在运行，那么在

onDownloadComplete

中会得到不同的时间戳。尝试将文件名保存在局部变量中并重复使用：

private void downloadAndViewAttachment(String url) {

String extension = url.substring(url.lastIndexOf("."));
Log.v("extension", extension);

fileName = url.substring(url.lastIndexOf("/"));
fileName = fileName.replace("/", "");
Log.v("fileName", fileName);
final File file = new File(Environment.getExternalStoragePublicDirectory(getString(R.string.app_name)),   AppConstants.Attachments);
// Save complete Filename in variable.
final String fullFilename = AppUtils.getTimeStamp() + "_" + fileName;
AndroidNetworking.download(url, file.getPath(), fullFilename)
        .setPriority(Priority.HIGH)
        .build()
        .setDownloadProgressListener(new DownloadProgressListener() {
            @Override
            public void onProgress(long bytesDownloaded, long totalBytes) {

                AppUtils.showRequestDialog(mActivity);

            }
        })
        .startDownload(new DownloadListener() {
            @Override
            public void onDownloadComplete() {

                AppUtils.hideDialog(mActivity);
                AppUtils.showToastSort(mActivity, getString(R.string.download_succesfully));
                // Reuse variabel.
                openPdfFile(file.getPath() + "/" + fullFilename);
              

            }

            @Override
            public void onError(ANError anError) {

                AppUtils.hideDialog(mActivity);
                Log.v("downloadError", anError.getErrorBody());
                Log.v("downloadError", anError.getErrorDetail());
                Log.v("downloadError", String.valueOf(anError.getErrorCode()));
                AppUtils.showToastSort(mActivity, getString(R.string.something_error));

            }
        });

}

自从Android 7/N以来，Uri.fromFile（）不应该工作。除非您使用严格模式等恶劣行为。