Now I am already aware of several solutions out there that allow you to capture system audio and stream via DLNA; my first attempt was with BubbleUPNP's audio cast feature, and although it did what I was looking for I was less than happy with the time it takes to get music playing each and EVERY time I want to use it to stream.
So basically I have found a way to alleviate this with a combination of two applications. Essentially by the end of it I am now able to simply swipe down from the right side of my status bar and simply toggle all the different receivers in my home and car on and off. So if your someone like me, with a lot of audio receivers everywhere, this could be VERY useful, simply by alleviating the hassle of having to mess through so many menu's just to get a song playing. The only downside for some might be that both of these apps are PAID applications and so you might have to shell out some cash to get this up and running. But honestly I am more than willing to support these awesome developers.
So without further ado lets get to the good stuff.
1. Firstly you will need root as one of these apps require it.
2. The two apps you'll need for this are AirAudio and Snap Swipe Drawer
*I know there are other apps that can do it but AirAudio has a few advantages and a critical feature we will need. One it works with a ton of different streaming protocols including AirPlay, DLNA, AllPlay, Fire TV, Google Cast, etc. The critical piece of this software though is that it comes with togglable widgets which we will need to accomplish our goal of simplicity!!*
3. So now that you have both apps up and running open AirAudio first and make sure you locate and connect to all of the receivers your wanting to set up for quick access and least once. It has to connect at least once in order to be able to make a widget out of it. Also run through its settings and make sure everything is set to your liking. You might want to name each of your receivers something unique and simple as well.
4. Now that AirAudio is setup we can go into "Settings > Apps > AirAudio" and completely block all notifications for this app. Technically this is optional but it goes a long way to make this implementation clean and it keeps your notifications drawer free of clutter when its connected. Won't be a loss really since you can control the receivers volume with your hardware buttons anyway and your music app of choice most likely already has a notification.
5. Now we are going to make this truly powerful and convenient! AirAudio comes with some nice widgets that make toggling a receiver as simple as a single click. Only downside is that you can normally only have them on your home screen and they take up screen real estate, while also looking kinda out of place. Thanks tough to our second app: Snap Swipe Drawer, we can create a dropdown of widgets of our choosing that we can access from any screen, any time!
- Open Snap Swipe Drawer and open "preferences" from the top right menu. In here you can set it up to your liking. Most importantly do you want your drop down to come from the right, left or center when you swipe down from the status bar. You may also wish to enable the accessibility service to make the transitions and behavior smoother.
- Now go back to the front page and click the FAB button with the "+" in the bottom right corner. Choose AirAudio widget and choose your first receiver! Once its in the list click it and configure it so that Columns=4 and Rows=1. This is the most pleasant for my taste at least but feel free to configure to yours if you like. Thats it, Now swipe down from whichever side you chose in "preferences" just as if your trying to open your notifications and a new menu will drop down containing your new widget!!
6. Profit!! Repeat for every receiver you need and there you go! You can now toggle audio streaming just as quickly, and painlessly as IOS users can, from any screen! And we have the added benefit of having more than just AirPlay available to us, compared to IOS, thanks to the power of Android!!!
I really hope this guide helps somebody else as much as it helped me. Not everybody uses streaming audio on the daily but for those that do this will be a game changer!!!
---Just a small tip to make it even better. I am an xposed user with GravityBox and in GB under "Satusbar tweaks > Quicksettings Management" I have "quick pulldown" set up from the left and also I have Snap Swipe Drawer setup to open from the right. I also have "auto switch quicksettings" in GB set to "When there are no notifications". Basically what this accomplishes is that if I want to see notifications I swipe down from the center. If I want to get right to my quick toggles I swipe down from the left, and if I want to toggle a DLNA/AirPlay receiver I swipe down from the right.
---Also use your imagination, you can use any widget available SSD app so you can make your experience even more customized and useful by playing around with it some more and getting your moneys worth.