NotificationCompatにhttpから取得した画像を入れる

NotificationCompat.Builderは端末のPush通知を送る事ができる機能です。
setLargeIcon(Bitmap bitmap)というメソッドがあるのでそれを使って実装します。

AsyncTaskを使って画像URLをHTTPで取得し、
NotificationCompat.BuilderでBitmapを設定したPush通知を送信するクラスを書きます。

class SendNotificationBuilder extends AsyncTask<String, Void, Bitmap> {

  private String title;
  private String message;
  private String imageUrl;
  private Intent intent;

  public SendNotificationBuilder(Context context) {
    super();
    this.context = context;
  }

  public SendNotificationBuilder setTitle(String title) {
    this.title = title;
    return this;
  }

  public SendNotificationBuilder setMessage(String message) {
    this.message = message;
    return this;
  }

  public SendNotificationBuilder setImageUrl(String imageUrl) {
    this.imageUrl = imageUrl;
    return this;
  }

  public SendNotificationBuilder setIntent(Intent intent) {
    this.intent = intent;
    return this;
  }

  @Override
  protected Bitmap doInBackground(String... params) {
      if (imageUrl == null) return null;
      InputStream in;
      try {
        URL url = new URL(imageUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setDoInput(true);
        connection.connect();
        in = connection.getInputStream();
        Bitmap bitmap = BitmapFactory.decodeStream(in);
        return bitmap;
      } catch (MalformedURLException e) {
        e.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return null;
  }

  @Override
  protected void onPostExecute(Bitmap bitmap) {
    super.onPostExecute(bitmap);
    try {
      NotificationManagerCompat manager = 
          NotificationManagerCompat.from(getApplicationContext());
      NotificationCompat.Builder builder;
      builder = new NotificationCompat.Builder(context)
          .setContentTitle(title)
          .setContentText(text);

      builder.setSmallIcon(R.drawable.icon_app);
      builder.setColor(ContextCompat.getColor(context, R.color.white));
      if (bitmap != null) {
        builder.setLargeIcon(bitmap);
      }
      builder.setAutoCancel(true);

      PendingIntent contentIntent = PendingIntent.getActivity(
          getApplicationContext(), REQUEST_ID,
          intent, PendingIntent.FLAG_ONE_SHOT);
      builder.setContentIntent(contentIntent);
      manager.notify(NOTIFY_ID, builder.build());
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

呼び出します。

new SendNotificationBuilder(getApplicationContext())
    .setTitle(title)
    .setText(text)
    .setImageUrl(imageUrl)
    .setIntent(intent)
    .execute();