Android How to - Use DownloadManager to download

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The following code shows how to Use DownloadManager to download.

Example

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.examples.downloader"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".DownloadActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
    <uses-sdk android:minSdkVersion="9" />

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

Main layout xml file

<?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"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="hello"
    />
</LinearLayout>

Main Activity Java code

//from w  ww  .  j a  va 2s.c  o  m
package com.java2s.myapplication4.app;

import java.io.FileInputStream;

import android.app.Activity;
import android.app.DownloadManager;
import android.app.DownloadManager.Request;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.preference.PreferenceManager;
import android.util.Log;
import android.widget.ImageView;

public class MainActivity extends Activity {

    private static final String DL_ID = "downloadId";
    private SharedPreferences prefs;
    private DownloadManager dm;
    private ImageView imageView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        imageView = new ImageView(this);
        setContentView(imageView);

        prefs = PreferenceManager.getDefaultSharedPreferences(this);
        dm = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
    }

    @Override
    public void onResume() {
        super.onResume();
        if(!prefs.contains(DL_ID)) {
            Uri resource = Uri.parse("http://www.java2s.com");
            DownloadManager.Request request = new DownloadManager.Request(resource);
            request.setAllowedNetworkTypes(Request.NETWORK_MOBILE | Request.NETWORK_WIFI);
            request.setAllowedOverRoaming(false);
            request.setTitle("Download Sample");
            long id = dm.enqueue(request);
            prefs.edit().putLong(DL_ID, id).commit();
        } else {
            queryDownloadStatus();
        }
        registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
    }

    @Override
    public void onPause() {
        super.onPause();
        unregisterReceiver(receiver);
    }

    private BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            queryDownloadStatus();
        }
    };

    private void queryDownloadStatus() {
        DownloadManager.Query query = new DownloadManager.Query();
        query.setFilterById(prefs.getLong(DL_ID, 0));
        Cursor c = dm.query(query);
        if(c.moveToFirst()) {
            int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
            switch(status) {
                case DownloadManager.STATUS_PAUSED:
                case DownloadManager.STATUS_PENDING:
                case DownloadManager.STATUS_RUNNING:
                    break;
                case DownloadManager.STATUS_SUCCESSFUL:
                    try {
                        ParcelFileDescriptor file = dm.openDownloadedFile(prefs.getLong(DL_ID, 0));
                        FileInputStream fis = new ParcelFileDescriptor.AutoCloseInputStream(file);
                        imageView.setImageBitmap(BitmapFactory.decodeStream(fis));
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    break;
                case DownloadManager.STATUS_FAILED:
                    dm.remove(prefs.getLong(DL_ID, 0));
                    prefs.edit().clear().commit();
                    break;
            }
        }
    }
}

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