如何访问Android下载管理器的百分比？

Question

我在我的应用程序中使用Android下载管理器。如何访问下载进度（例如通知中的下载百分比），以便在活动内显示该百分比的进度条？

这是我的下载文件方法：

////////////////////////////////////////////////////////////
//================== btn download set on click listner  ===========
////////////////////////////////////////////////////////////

holder.btnDownload.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        dm = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
        Uri downloadUri = Uri.parse(questionha.get(position).getQuestionDownLink());
        if (!Uri.EMPTY.equals(downloadUri)) {

            Request request = new Request(downloadUri);
            request.setTitle(questionha.get(position).getQuestionTitle());
            request.setDescription("Downloading ....");
            request.setDestinationInExternalFilesDir(v.getContext(), "downloaded", questionha.get(position).getQuestionDownFileName());
            enqueue = dm.enqueue(request);
        }else {
            Log.i("Download manager","Download manager url is null !");
        }

    }
});

- majid

Answer 1

在搜索 Android 下载管理器文档后，我找到了以下解决方案：

String urlDownload = "something";
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(urlDownload));

request.setDescription("This is Desc");
request.setTitle("download picsArt");
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);

                }
            });
            cursor.close();
        }

    }
}).start();

- majid

---

但是这段代码对我来说是有效的，并且更新了进度条，你觉得呢？ - majid

我认为你可能在没有特别好的理由的情况下浪费电池，因为你不停地检查那个值。我不知道是否有一个可以监听该事件或其他方式，但至少在从数据库查询后再进行查询之前应等待一段时间。 - Joachim Sauer

你可以使用ContentObserver来监视变化，而不是循环：`registerContentObserver( Uri.parse( "content://downloads/my_downloads" ), true, YOUR_OBSERVER );` - cwbowron