Android Notification is not showing Colour Icon in Marshmallow
First : Its not from Marshmallow, Notification icon started turning out WHITE from Lollipop itself.
Checkout http://developer.android.com/design/style/iconography.html you will see that the white style is how notifications are meant to be displayed in Android Lollipop.
In Android Lollipop, Google also suggests you to use a color that will be displayed behind the (white) notification icon - https://developer.android.com/about/versions/android-5.0-changes.html
Second : Solution to this is setting LargeIcon
to Notification Builder
Bitmap largeIcon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
NotificationCompat.Builder builder = new NotificationCompat.Builder(context)
.setSmallIcon(R.drawable.ic_launcher)
.setLargeIcon(largeIcon)
.setContentText(data)
.setContentTitle("Notification from Parse")
.setContentIntent(pendingIntent);
then, your Notification will look something like this :
You can also set the color to background of Notification Icon by using .setColor()
.