使用LocalBroadcastManager注册BroadcastReceiver时，不会调用onReceive

Question

I've created a BroadcastReceiver to receive ACTION_DOWNLOAD_COMPLETE when my app starts downloading something using DownloadManager . As I want to capture ACTION_DOWNLOAD_COMPLETE only when downloading is started from my app, I've used LocalBroadcastManager .

But onReceiver is not being called at all. DownloadManager app shows that download is complete but onReceive is not triggered. When I use registerReceiver it works as expected. But this would let app being notified even if downloading is started by some other app. So LocalBroadcastManager is desired.

MainActivity

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        downloadReceiver = new DownloadReceiver();

        LocalBroadcastManager.getInstance(this).registerReceiver(downloadReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));           

        downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
        if(FileHelper.isStorageAvailable()) {
            DownloadManager.Request request = new DownloadManager.Request(Uri.parse("http://example.com/image.jpg"));
            downloadManager.enqueue(request);
        }
    }
    @Override
    protected void onPause() {
        LocalBroadcastManager.getInstance(this).unregisterReceiver(downloadReceiver);
        super.onPause();
    }

DownloadReciever

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {

            long downloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, 0);
            downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);

            DownloadManager.Query query = new DownloadManager.Query();
            query.setFilterById(downloadId);
            Cursor c = downloadManager.query(query);

            if (c.moveToFirst()) {
                int columnIndex = c.getColumnIndex(DownloadManager.COLUMN_STATUS);
                if (DownloadManager.STATUS_SUCCESSFUL == c.getInt(columnIndex)) {                        
                    String title = c.getString(c.getColumnIndex(DownloadManager.COLUMN_TITLE));                 
                    Toast.makeText(context, title, Toast.LENGTH_SHORT).show();
                }
            }
        }
    }

It simply don't call onRecieve as it should. Point out if I'm doing something wrong here. Been stuck here for quite time now. I can't use registerReceiver as I need to track download complete action only if my app starts downloading.

Answer 1

As I want to capture ACTION_DOWNLOAD_COMPLETE only when downloading is started from my app, I've used LocalBroadcastManager.

That is not going to work. DownloadManager does the download in a separate process, and it will use a system broadcast. The only broadcasts that you can receive via LocalBraodcastManager are the ones that you broadcast via LocalBroadcastManager .