使用 LocalBroadcastManager 注册 BroadcastReceiver 时未调用 onReceive

Question

我创建了一个 BroadcastReceiver 以在我的应用开始使用 DownloadManager 下载内容时接收 ACTION_DOWNLOAD_COMPLETE。因为我只想在从我的应用程序开始下载时捕获 ACTION_DOWNLOAD_COMPLETE，所以我使用了 LocalBroadcastManager.

但是 onReceiver 根本没有被调用。 DownloadManager 应用程序显示下载完成但 onReceive 未触发。当我使用 registerReceiver 时，它按预期工作。但这会让应用程序收到通知，即使下载是由其他应用程序开始的。所以需要 LocalBroadcastManager。

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();
    }

下载接收者

    @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();
                }
            }
        }
    }

它根本没有按应有的方式调用 onRecieve。指出我是否在这里做错了什么。现在被困在这里很长一段时间了。我无法使用 registerReceiver，因为只有当我的应用程序开始下载时我才需要跟踪下载完成操作。

Answer 1

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

那是行不通的。 DownloadManager 在单独的进程中进行下载，并且会使用系统广播。您可以通过 LocalBraodcastManager 接收的只有广播是 您通过 LocalBroadcastManager 广播 的广播。

使用 LocalBroadcastManager 注册 BroadcastReceiver 时未调用 onReceive

onReceive not being called when BroadcastReceiver is registered using LocalBroadcastManager

android

broadcastreceiver

android-download-manager

localbroadcastmanager