Question

我正在通过DownloadManager（API 28）下载图片。图片已成功下载并显示在ImageView中。我想找出文件名。但是getUriForDownloadedFile（）返回null。为什么？

private void dowloadfile() {
    Uri uri = Uri.parse(editText.getText().toString());
    DownloadManager.Request request = new DownloadManager.Request(uri);
    request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
    request.setAllowedOverRoaming(false);
    request.setVisibleInDownloadsUi(true);
    request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "picture." + extension);

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

    refid = downloadManager.enqueue(request);
    Uri u = downloadManager.getUriForDownloadedFile(refid);
}

Answer 1

入队后，下载是一个异步操作，下载完成后可能会分配uri，您需要收听您的接收器并传递ID以获得

为什么getUriForDownloadedFile（）返回null

1 个答案: