The Android DownloadManager introduced in Android 2.3. (API 9) is a system service which allows to handle long-running HTTP downloads in the background and notify the triggering application via a broadcast receiver once the download is finished.

Here is a little example for using the DownloadManager. The project will be called “de.vogella.android.downloadmanager” with the activity “DownloadManagerActivity” based on Android API9 or higher.

Change “main.xml” to the following.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical" android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<Button android:text="Start Download" android:id="@+id/button1"
		android:layout_width="wrap_content" android:layout_height="wrap_content"
		android:onClick="onClick"></Button>
	<Button android:text="View Downloads" android:id="@+id/button2"
		android:layout_width="wrap_content" android:layout_height="wrap_content"
		android:onClick="showDownload"></Button>
	<ImageView android:layout_height="wrap_content" android:id="@+id/imageView1"
		android:src="@drawable/icon" android:layout_width="wrap_content"></ImageView>
</LinearLayout>

Change the code of your activity to the following.

package de.vogella.android.downloadmanager;

import android.app.Activity;
import android.app.DownloadManager;
import android.app.DownloadManager.Query;
import android.app.DownloadManager.Request;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;

public class DownloadManagerActivity extends Activity {
	private long enqueue;
	private DownloadManager dm;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		BroadcastReceiver receiver = new BroadcastReceiver() {
			@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);
					Query query = new Query();
					query.setFilterById(enqueue);
					Cursor c = dm.query(query);
					if (c.moveToFirst()) {
						int columnIndex = c
								.getColumnIndex(DownloadManager.COLUMN_STATUS);
						if (DownloadManager.STATUS_SUCCESSFUL == c
								.getInt(columnIndex)) {

							ImageView view = (ImageView) findViewById(R.id.imageView1);
							String uriString = c
									.getString(c
											.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
							view.setImageURI(Uri.parse(uriString));
						}
					}
				}
			}
		};

		registerReceiver(receiver, new IntentFilter(
				DownloadManager.ACTION_DOWNLOAD_COMPLETE));
	}

	public void onClick(View view) {
		dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
		Request request = new Request(
				Uri.parse("http://www.vogella.de/img/lars/LarsVogelArticle7.png"));
		enqueue = dm.enqueue(request);

	}

	public void showDownload(View view) {
		Intent i = new Intent();
		i.setAction(DownloadManager.ACTION_VIEW_DOWNLOADS);
		startActivity(i);
	}
}

Also add the permission to go to the internet to your app.

If you implemented this example you have an Android application which can download my picture (sorry for this ) and allow you to switch to the download manager to see the finished downloads.

Hope this helps.

You find me also on Twitter.