Android - DownloadManager / BroadcastReceiver 多次调用

Question

我正在使用DownloadManager来处理应用程序中的下载，我想在下载完成时通知用户。

我正在使用运行良好的以下代码

 public void downloaddownload(View v){
        View v2 = (View) v.getParent();
        TextView urlView = (TextView) v2.findViewById(R.id.url);
        String urlString = (String) urlView.getText().toString();
        TextView artistView2 = (TextView) v2.findViewById(R.id.artist);
        final String artistString = (String) artistView2.getText().toString();
        TextView titleView2 = (TextView) v2.findViewById(R.id.title);
        final String titleString = (String) titleView2.getText().toString();
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(urlString));
        request.setDescription(titleString);
        request.setTitle(artistString);
        // in order for this if to run, you must use the android 3.2 to compile your app
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        }
        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_MUSIC + "/folder", titleString + " - " + artistString + ".mp3");
        Toast.makeText(mainContext, "Downloading " + titleString + " - " + artistString, Toast.LENGTH_SHORT).show();
        // get download service and enqueue file
        DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
        manager.enqueue(request);
        onComplete = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                // TODO Auto-generated method stub
                Toast.makeText(mainContext, "Download " " + titleString + " - " + artistString + "" completed", Toast.LENGTH_LONG).show();
            }
         };
         registerReceiver(onComplete, new IntentFilter(
                    DownloadManager.ACTION_DOWNLOAD_COMPLETE));

    }

问题是以前的下载也调用了onReceive方法。

假设我下载 a.mp3、b.mp3 和 c.mp3，当 a.mp3 完成时，我收到 a.mp3 完成，当 b.mp3 完成时，我收到 a.mp3 完成，然后一个新的 toast b.mp3 完成......

我怎样才能防止这种情况？谢谢。

Answer 1

每次下载文件时，Yo都会注册一个BroadcastReceiver。这意味着，第二次下载文件时，您将注册两个接收器。您可能应该在工作完成后使用 unregisterReceiver() 取消注册它们（可能在 onReceive() 年）。

Answer 2

long downloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, 0);
Query query = new Query();
query.setFilterById(downloadId);
Cursor cur = manager.query(query);
    if (cur.moveToFirst()) {
        int columnIndex = cur.getColumnIndex(DownloadManager.COLUMN_STATUS);
        if (DownloadManager.STATUS_SUCCESSFUL == cur.getInt(columnIndex)) {
            titleString=cur.getString(cur.getColumnIndex(DownloadManager.COLUMN_TITLE));}

您应该使用它来获取单个下载的标题字符串。 因为每个下载都有自己的 ID .我知道回答为时已晚，但将来可能会对其他人有所帮助......