ContentResolver openInputStream在后台下載文件

Question

因此，我正在嘗試下載一個大文件。 所以自然地，我的第一步是打開流

RNFetchBlob.RCTContext.getContentResolver().openInputStream(Uri.parse(fromUri));

我的問題是，這不是快速工作而只是打開流，而是實際上在后台下載內容。 我怎么知道？ 好吧，這個命令會阻塞大約5分鍾，然后當我從流中讀取時，它是瞬時的。

我可以使此操作阻止在后台下載嗎？ 我想通知用戶有關進度，而不僅僅是等待。

編輯：明確地說，我正在使用content：// URI作為資源

Answer 1

這是通過網絡讀取文件的錯誤方法，您需要使用特定於網絡的方法。

HttpURLConnection request = 
    (HttpURLConnection)(new URL(Uri.parse(fromUri)).openConnection());
// Connect to the server, expect a delay and draw a progress bar
request.connect();
// This will read HTTP headers with content length, expect another delay
// Must be called before request.getContentLength()
request.getInputStream();
// Get the size of your file, to draw your progress bar properly
long total = request.getContentLength();
// Now you can finally start reading the data
InputStream input = request.getInputStream();

Answer 2

對於長時間運行的HTTP下載，你可以使用DownloadManager ，例如像，並顯示下載進度這個的問題維克多拉爾特 ：

  String urlDownload = <YOUR_URL>; DownloadManager.Request request = new DownloadManager.Request(Uri.parse(urlDownload)); request.setDescription("Testando"); request.setTitle("Download"); request.allowScanningByMediaScanner(); request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED); request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,"teste.zip"); final DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE); final long downloadId = manager.enqueue(request); final ProgressBar mProgressBar = (ProgressBar) findViewById(R.id.progressBar1); new Thread(new Runnable() { @Override public void run() { boolean downloading = true; while (downloading) { DownloadManager.Query q = new DownloadManager.Query(); q.setFilterById(downloadId); Cursor cursor = manager.query(q); cursor.moveToFirst(); int bytes_downloaded = cursor.getInt(cursor .getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR)); int bytes_total = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES)); if (cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS)) == DownloadManager.STATUS_SUCCESSFUL) { downloading = false; } final int dl_progress = (int) ((bytes_downloaded * 100l) / bytes_total); runOnUiThread(new Runnable() { @Override public void run() { mProgressBar.setProgress((int) dl_progress); } }); Log.d(Constants.MAIN_VIEW_ACTIVITY, statusMessage(cursor)); cursor.close(); } } }).start();