Downloader.java

/***
  Copyright (c) 2008-2017 CommonsWare, LLC
  Licensed under the Apache License, Version 2.0 (the "License"); you may not
  use this file except in compliance with the License. You may obtain a copy
  of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
  by applicable law or agreed to in writing, software distributed under the
  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
  OF ANY KIND, either express or implied. See the License for the specific
  language governing permissions and limitations under the License.
  
  Covered in detail in the book _The Busy Coder's Guide to Android Development_
    https://commonsware.com/Android
 */

package com.commonsware.android.downloader;

import android.app.IntentService;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.support.v4.content.FileProvider;
import android.util.Log;
import com.commonsware.cwac.netsecurity.TrustManagerBuilder;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class Downloader extends IntentService {
  private static final String AUTHORITY=
    BuildConfig.APPLICATION_ID+".provider";
  private static int NOTIFY_ID=1337;
  private static int FOREGROUND_ID=1338;

  public Downloader() {
    super("Downloader");
  }

  @Override
  public void onHandleIntent(Intent i) {
    File output=new File(getFilesDir(),
      i.getData().getLastPathSegment());

    startForeground(FOREGROUND_ID,
      buildForegroundNotification(output.getName()));

    try {
      if (output.exists()) {
        output.delete();
      }

      URL url=new URL(i.getData().toString());
      HttpURLConnection c=
        (HttpURLConnection)url.openConnection();
      TrustManagerBuilder tmb=
        new TrustManagerBuilder().withManifestConfig(this);

      tmb.applyTo(c);

      FileOutputStream fos=
        new FileOutputStream(output.getPath());
      BufferedOutputStream out=new BufferedOutputStream(fos);
      String mimeType=c.getHeaderField("Content-type");

      try {
        InputStream in=c.getInputStream();
        byte[] buffer=new byte[8192];
        int len=0;

        while ((len=in.read(buffer))>=0) {
          out.write(buffer, 0, len);
        }

        out.flush();
      }
      finally {
        fos.getFD().sync();
        out.close();
        c.disconnect();
      }

      raiseNotification(mimeType, output, null);
    }
    catch (Exception e2) {
      Log.e(getClass().getSimpleName(),
        "Exception downloading file", e2);
      raiseNotification(null, null, e2);
    }
    finally {
      stopForeground(true);
    }
  }

  private void raiseNotification(String mimeType, File output,
                                 Exception e) {
    NotificationCompat.Builder b=
      new NotificationCompat.Builder(this);

    b.setAutoCancel(true).setDefaults(Notification.DEFAULT_ALL);

    if (e==null) {
      b.setContentTitle(getString(R.string.download_complete))
        .setContentText(getString(R.string.fun))
        .setSmallIcon(android.R.drawable.stat_sys_download_done)
        .setTicker(getString(R.string.download_complete));

      Intent outbound=new Intent(Intent.ACTION_VIEW);
      Uri doc=
        FileProvider.getUriForFile(this, AUTHORITY, output);

      outbound.setDataAndType(doc, mimeType);
      outbound.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

      b.setContentIntent(
        PendingIntent.getActivity(this, 0, outbound, 0));
    }
    else {
      b.setContentTitle(getString(R.string.exception))
        .setContentText(e.getMessage())
        .setSmallIcon(android.R.drawable.stat_notify_error)
        .setTicker(getString(R.string.exception));
    }

    NotificationManager mgr=
      (NotificationManager)getSystemService(
        NOTIFICATION_SERVICE);

    mgr.notify(NOTIFY_ID, b.build());
  }

  private Notification buildForegroundNotification(String filename) {
    NotificationCompat.Builder b=new NotificationCompat.Builder(this);

    b.setOngoing(true);

    b.setContentTitle(getString(R.string.downloading))
      .setContentText(filename)
      .setSmallIcon(android.R.drawable.stat_sys_download)
      .setTicker(getString(R.string.downloading));

    return(b.build());
  }
}