Android Download Manager Tutorial: How to Download Files using Download Manager from Internet

We have come up with another amazing tutorial on how to download one or more files using Android Download Manager. The download manager was introduced in Android 2.3 (API level 9). One big advantage of Android Download Manager is that it optimizes the handling of long-running downloads in the background. The download manager handles HTTP connections, monitors connectivity changes, reboots, and ensures each download completes successfully. If you want to download large files/streaming, then you can’t use Retrofit or Volley, both recommend using DownloadManager instead, which supports resuming and progress notifications.

In this post, we will cover the following subjects:

1. Download Image and Music at the same time using Android Download Manager.
2. Display Status of all downloads at any time using a switch.
3. Save them to a particular location in external drive.
4. Sending notification when download completes.
5. Ability to Cancel all downloads.

We will download Image and Music from the following URL:

Pre-requisites

1. Android Studio installed on your PC (Unix or Windows).
2. A real time android device (Smartphone or Tablet) configured with Android Studio.
3. A basic knowledge of Android lifecycle and different classes & functions used in Android Studio.

Creating a New Project

Add Permissions

Add the following permission to your AndroidManifest.xml file:

AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Now, we will describe each topic in detail through each function which can be implemented through Android Download Manager. We have made separate functions for download data, show status, complete download notification and cancel downloads.

Generate URI

First, we will have to generate URI from URL. So here, we will generate two URI each for Image and Music URL.

Uri image_uri = Uri.parse("http://androidtutorialpoint.comli.com/DownloadManager/Beauty.jpg");

Uri music_uri = Uri.parse
("http://androidtutorialpoint.comli.com/DownloadManager/AndroidDownloadManager.mp3");

Download Data from URL using Android Download Manager

DownloadData() function will be used to download data from the internet.

DownloadData

private long DownloadData (Uri uri, View v) {

        long downloadReference;

        // Create request for android download manager
        downloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
        DownloadManager.Request request = new DownloadManager.Request(uri);

        //Setting title of request
        request.setTitle("Data Download");

        //Setting description of request
        request.setDescription("Android Data download using DownloadManager.");

        //Set the local destination for the downloaded file to a path 
        //within the application's external files directory
        if(v.getId() == R.id.DownloadMusic)
          request.setDestinationInExternalFilesDir(MainActivity.this, 
          Environment.DIRECTORY_DOWNLOADS,"AndroidTutorialPoint.mp3");
        else if(v.getId() == R.id.DownloadImage)
          request.setDestinationInExternalFilesDir(MainActivity.this, 
          Environment.DIRECTORY_DOWNLOADS,"AndroidTutorialPoint.jpg");

        //Enqueue download and save into referenceId
        downloadReference = downloadManager.enqueue(request);

        Button DownloadStatus = (Button) findViewById(R.id.DownloadStatus);
        DownloadStatus.setEnabled(true);
        Button CancelDownload = (Button) findViewById(R.id.CancelDownload);
        CancelDownload.setEnabled(true);

        return downloadReference;
    }

Description of the above code:

1. downloadReference: It is a unique id that we will refer for specific download request.
2. request: Instance of DownloadManager will be created through getSystemService by passing DOWNLOAD_SERVICE. A new request is generated in the next statement using DownloadManager.Request(uri).
3. setDestinationInExternalFilesDir: This will be used to save file in external downloads folder.
4. downloadManager.enqueue(request): Enqueue a new download corresponding to request. The download will start automatically once the download manager is ready to execute it and connectivity is available.

Check Download Status

Check_Image_Status() function will be used to get the status of the Image Download. Refer to the following code:

Check_Image_Status

private void Check_Image_Status(long Image_DownloadId) {

        DownloadManager.Query ImageDownloadQuery = new DownloadManager.Query();
        //set the query filter to our previously Enqueued download
        ImageDownloadQuery.setFilterById(Image_DownloadId);

        //Query the download manager about downloads that have been requested.
        Cursor cursor = downloadManager.query(ImageDownloadQuery);
        if(cursor.moveToFirst()){
            DownloadStatus(cursor, Image_DownloadId);
        }
    }

Description of above code:

1. DownloadManager.Query(): This is used to filter Android download manager queries. Here, we are providing Image_DownloadId in setFilterById() to include only downloads with given Id.
2. downloadManager.query(ImageDownloadQuery): This is used to Query the Android download manager about downloads that have been requested.
3. Cursor: A Cursor over the result set of downloads, with columns consisting of all the COLUMN_* constants. Now this cursor will be used to get the status of download in DownloadStatus() function.

DownloadStatus

private void DownloadStatus(Cursor cursor, long DownloadId){

        //column for download  status
        int columnIndex = cursor.getColumnIndex(DownloadManager.COLUMN_STATUS);
        int status = cursor.getInt(columnIndex);
        //column for reason code if the download failed or paused
        int columnReason = cursor.getColumnIndex(DownloadManager.COLUMN_REASON);
        int reason = cursor.getInt(columnReason);
        //get the download filename
        int filenameIndex = cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_FILENAME);
        String filename = cursor.getString(filenameIndex);

        String statusText = "";
        String reasonText = "";

        switch(status){
            case DownloadManager.STATUS_FAILED:
                statusText = "STATUS_FAILED";
                switch(reason){
                    case DownloadManager.ERROR_CANNOT_RESUME:
                        reasonText = "ERROR_CANNOT_RESUME";
                        break;
                    case DownloadManager.ERROR_DEVICE_NOT_FOUND:
                        reasonText = "ERROR_DEVICE_NOT_FOUND";
                        break;
                    case DownloadManager.ERROR_FILE_ALREADY_EXISTS:
                        reasonText = "ERROR_FILE_ALREADY_EXISTS";
                        break;
                    case DownloadManager.ERROR_FILE_ERROR:
                        reasonText = "ERROR_FILE_ERROR";
                        break;
                    case DownloadManager.ERROR_HTTP_DATA_ERROR:
                        reasonText = "ERROR_HTTP_DATA_ERROR";
                        break;
                    case DownloadManager.ERROR_INSUFFICIENT_SPACE:
                        reasonText = "ERROR_INSUFFICIENT_SPACE";
                        break;
                    case DownloadManager.ERROR_TOO_MANY_REDIRECTS:
                        reasonText = "ERROR_TOO_MANY_REDIRECTS";
                        break;
                    case DownloadManager.ERROR_UNHANDLED_HTTP_CODE:
                        reasonText = "ERROR_UNHANDLED_HTTP_CODE";
                        break;
                    case DownloadManager.ERROR_UNKNOWN:
                        reasonText = "ERROR_UNKNOWN";
                        break;
                }
                break;
            case DownloadManager.STATUS_PAUSED:
                statusText = "STATUS_PAUSED";
                switch(reason){
                    case DownloadManager.PAUSED_QUEUED_FOR_WIFI:
                        reasonText = "PAUSED_QUEUED_FOR_WIFI";
                        break;
                    case DownloadManager.PAUSED_UNKNOWN:
                        reasonText = "PAUSED_UNKNOWN";
                        break;
                    case DownloadManager.PAUSED_WAITING_FOR_NETWORK:
                        reasonText = "PAUSED_WAITING_FOR_NETWORK";
                        break;
                    case DownloadManager.PAUSED_WAITING_TO_RETRY:
                        reasonText = "PAUSED_WAITING_TO_RETRY";
                        break;
                }
                break;
            case DownloadManager.STATUS_PENDING:
                statusText = "STATUS_PENDING";
                break;
            case DownloadManager.STATUS_RUNNING:
                statusText = "STATUS_RUNNING";
                break;
            case DownloadManager.STATUS_SUCCESSFUL:
                statusText = "STATUS_SUCCESSFUL";
                reasonText = "Filename:\n" + filename;
                break;
        }

        if(DownloadId == Music_DownloadId) {

            Toast toast = Toast.makeText(MainActivity.this,
                    "Music Download Status:" + "\n" + statusText + "\n" +
                            reasonText,
                    Toast.LENGTH_LONG);
            toast.setGravity(Gravity.TOP, 25, 400);
            toast.show();

        }
        else {

            Toast toast = Toast.makeText(MainActivity.this,
                    "Image Download Status:"+ "\n" + statusText + "\n" +
                            reasonText,
                    Toast.LENGTH_LONG);
            toast.setGravity(Gravity.TOP, 25, 400);
            toast.show();

            // Make a delay of 3 seconds so that next toast (Music Status) will not merge with this one.
            final Handler handler = new Handler();
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                }
            }, 3000);
        }
    }

The above code is pretty much self explanatory. We are simply printing status according to the value of COLUMN_REASON returned by Android Download Manager.

Similarly, we have made function for checking status of Music file, i.e., Check_Music_Status().

Cancel all Downloads

To cancel a download, we will simply use:

downloadManager.remove(Image_DownloadId);
downloadManager.remove(Music_DownloadId);

The Broadcast Receivers

The last part of our tutorial is broadcast receiver. Android DownloadManager sends ACTION_DOWNLOAD_COMPLETE broadcast intent when a download completes. So we will set filter when download completes and registers receiver:

IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
registerReceiver(downloadReceiver, filter);

private BroadcastReceiver downloadReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {

            //check if the broadcast message is for our enqueued download
            long referenceId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);

            if(referenceId == Image_DownloadId) {

                Toast toast = Toast.makeText(MainActivity.this,
                        "Image Download Complete", Toast.LENGTH_LONG);
                toast.setGravity(Gravity.TOP, 25, 400);
                toast.show();
            }
            else if(referenceId == Music_DownloadId) {

                Toast toast = Toast.makeText(MainActivity.this,
                        "Music Download Complete", Toast.LENGTH_LONG);
                toast.setGravity(Gravity.TOP, 25, 400);
                toast.show();
            }
        }
    };

So in the above code, broadcast Intent is received, its referenceId is compared and accordingly Toast message is displayed.

So finally, we have covered all aspects of Android Download Manager. Still, if you have any doubts or suggestions, please comment or mail us.