Android 从文件目录打开文件

您好，我已将一个文件从url保存到我的文件目录。并将广播恢复设置为在下载完成时检测，然后触发操作视图，以选择在哪个应用程序中打开它。这一切都很好，但当我选择另一个应用程序时，它无法显示文件。如果我从通知中心选择该文件，它会很好地打开，因此它肯定会下载加载到文件目录中，但不知道从我的应用程序打开时为什么会加载

DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
                            request.setTitle(filename);
                            // in order for this if to run, you must use the android 3.2 to compile your app
                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                                request.allowScanningByMediaScanner();
                                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                            }

                            ContextWrapper c = new ContextWrapper(getBaseContext());
                            final String filePath = c.getFilesDir().getPath() + "/";
                            Log.v("Search", "filePath = " + filePath);
                            request.setDestinationInExternalFilesDir(getBaseContext(), filePath, filename);

                            // get download service and enqueue file
                            DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
                            manager.enqueue(request);
                            Toast.makeText(getBaseContext(), "Downloading...", Toast.LENGTH_LONG).show();

                            BroadcastReceiver onComplete = new BroadcastReceiver() {


                                @Override
                                public void onReceive(Context context, Intent intent) {

                                    String path = getFilesDir().getPath() +"/" + filename;
                                    File f = new File(path); 
                                    Log.v("Search", "path = " + path);
                                    String fileExt = Global.getFileExt(filename);
                                    MimeTypeMap myMime = MimeTypeMap.getSingleton();

                                    Intent newIntent = new Intent(Intent.ACTION_VIEW);

                                    String mimeType = myMime.getMimeTypeFromExtension(fileExt);
                                    newIntent.setDataAndType(Uri.fromFile(f), mimeType);
                                    newIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                    try {
                                        context.startActivity(newIntent);
                                    } catch (android.content.ActivityNotFoundException e) {
                                        Toast.makeText(context, "No handler for this type of file.", 4000).show();
                                    }
                                }


                            };

                            registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));

                        }