Question

如何使用两个值计算文件下载速度1.总文件大小和2.Total Bytes正在下载。

@Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        if (v.getId() == R.id.start_ed) {
            DownloadManager.Request request = new DownloadManager.Request(
                    Uri.parse(durl));
            request.setTitle("File Download");
            request.setDescription("file is being download");

            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
            String nof = URLUtil.guessFileName(durl, null,
                    MimeTypeMap.getFileExtensionFromUrl(durl));

            request.setDestinationInExternalPublicDir(
                    Environment.DIRECTORY_DOWNLOADS, nof);

            final DownloadManager downloadManager = (DownloadManager) MainActivity.this
                    .getSystemService(Context.DOWNLOAD_SERVICE);
            // long id = downloadManager.enqueue(request); //This is to get the
            // id of the download.
            final long download_id = downloadManager.enqueue(request);

            final ProgressBar mProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
            final TextView current_tvm = (TextView) findViewById(R.id.current_tv);
            final TextView totl_tv = (TextView) findViewById(R.id.totalsize);
            new Thread(new Runnable() {

                @Override
                public void run() {

                    boolean downloading = true;

                    while (downloading) {

                        DownloadManager.Query q = new DownloadManager.Query();
                        q.setFilterById(download_id);

                        Cursor cursor = downloadManager.query(q);
                        cursor.moveToFirst();
                        final int bytes_downloaded = cursor.getInt(cursor
                                .getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
                        final 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() {
                                // totl_tv.setText(bytes_total);
                                // current_tvm.setText(bytes_downloaded);
                                String i = android.text.format.Formatter
                                        .formatFileSize(MainActivity.this,
                                                bytes_downloaded);

                                System.out.println(i);
                                current_tvm.setText(i);
                                mProgressBar.setProgress((int) dl_progress);

                            }
                        });

                        // Log.d(Constants.MAIN_VIEW_ACTIVITY,
                        // statusMessage(cursor));
                        cursor.close();
                    }

                }
            }).start();

        }
    }

现在我有两个值bytes_downloaded和一个文件的bytes_total，如何使用这两个值计算文件下载速度。在此先感谢。

Answer 1

由于您已经拥有bytes_downloaded值，现在只需要时间维度。

bytes_downloaded / seconds taken = speed in bytes per second

如果下载10000字节花费10秒钟，则下载速度为

10000 / 10 = 1000 bps = 8 kbps

计算速度不需要总文件大小，但需要计算estimated time to completion。

Answer 2

您需要进行抽样，即拥有一个静态变量，该变量将具有下载的总字节数。对于采样，您决定使用秒，即在1000ms后检查下载的字节值。现在您需要运行一个异步任务（它将检查您下载的字节数，并在一个预定义间隔为1000毫秒的循环内执行采样工作）并且它应该以计算的速度不断更新（使用发布API）您的UI。 / p>

如何使用bytes_downloaded和bytes_total Android / Java测量下载速度

2 个答案: