我尝试使用 DownloadManager 执行下载文件.除 LG 设备外，一切正常。这是我的代码:

private void downloadFile(FileInfo fileInfo) {
    private DownloadManager manager = (DownloadManager) MyApp.getSingleton().
            getApplicationContext().getSystemService(Context.DOWNLOAD_SERVICE);

    DownloadManager.Request request = new DownloadManager.Request(Uri.parse("https://"
            + MyPreference.getInstance().getBaseUrl()
            + "/api/v3/files/"
            + fileId
            + "/get"));

    request.setDescription(MyApp.getSingleton().getApplicationContext().getString(R.string.downloading));
    request.setTitle(fileInfo.getmName());
    request.addRequestHeader("Authorization", "Bearer " + MyPreference.getInstance().getAuthToken());
    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    File dir = new File(FileUtil.getInstance().getDownloadedFilesDir());
    if(!dir.exists()){
        dir.mkdirs();
    }
    request.setDestinationUri(Uri.fromFile(new File(FileUtil.getInstance().getDownloadedFilesDir() + File.separator + fileInfo.getmName())));

    downloadId = manager.enqueue(request);

    new Thread(() -> {

        boolean downloading = true;
        while (downloading) {

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

            Cursor cursor = manager.query(q);
            cursor.moveToFirst();
            int bytes_downloaded = 0;
            long bytes_total = 0;
            try {
                bytes_downloaded = cursor.getInt(cursor
                        .getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
                bytes_total = cursor.getInt(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
            } catch (CursorIndexOutOfBoundsException e) {
                e.printStackTrace();
                cursor.close();
                break;
            } catch (IllegalArgumentException e){
                e.printStackTrace();
                cursor.close();
                break;
            }
            if (cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS)) == DownloadManager.STATUS_FAILED) {
                downloading = false;
                cursor.close();
                onDownloadFail();
                break;
            } else if (cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS)) == DownloadManager.STATUS_SUCCESSFUL) {
                downloading = false;
                cursor.close();
                break;
            }

            if (bytes_total > 0) {
                final int dl_progress = (int) ((bytes_downloaded * 100L) / bytes_total);
                    onProgress(dl_progress);
            }
            cursor.close();
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

    }).start();
}

在 LG 设备线上

bytes_total = cursor.getInt(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));

返回-1。 下载通知出现在通知栏中，并在几毫秒后立即消失。无一异常(exception)，没有人进入这段代码

if (cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS)) == DownloadManager.STATUS_FAILED) {
                downloading = false;
                cursor.close();
                onDownloadFail();
                break;
            }
else if (cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS)) == DownloadManager.STATUS_SUCCESSFUL) {
                downloading = false;
                cursor.close();
                break;
            }

什么都没有。所以内部 while() 循环永远工作。 在 LG D802 和 LG G3 S 设备上测试。这两种设备表现出相同的行为。

最佳答案

我遇到了同样的问题，并找到了解决方案。在初始化下载管理器之前，您需要确保所有目录都存在。 示例:在我的例子中，我的文件路径是 /storage/emulated/0/MyFolder/n.jpeg 所以我必须确保 MyFolder 目录在初始化下载管理器之前存在。

关于android - 下载管理器不适用于 LG 设备，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41679016/