How does one live a life of charity and still be able to support themselves?

Very simple... You give in ways that you can .. Not just monetarily. Volunteer! Donate your time and what money you can afford to donate... Budget for it. 

There are many ways to offer things to those who need it. things that you may already take for granted yourself.  Like... toiletries that are provided for guests in hotel rooms. Take them home, and give them to someone who could use them.  Go through your closet. and give away articles that you don't use anymore .. especially, socks, underwear, warm clothes, coats, hats, mitts, winter boots, shoes .. etc etc. Donate them to charities or actually give them out personally to people you see that could use them.

you donate a portion of what you can efford

I give till it hurts but I still survive

It's not that hard. Your question is a bit blur to me and i red the comments and it turned out more blur!

However, from what i understood, i can answer as "it is not that hard"  that's why i find your question strange to my sense!

Someone do charity as much as it don't harm themselves in order to keep supporting themselves.

For instance when i earn thousands of dollar each month and millions or even billions each year, and my money is not suppose to end. It's a business money and i have it in a cycle. I have all my supports and my most of the needs are filled and i know it will be filled for long years! So then i spend part of my money in cycle of charity, big and wide projects, how big i want my charity be is in my own hands according to my own money. Regardless of the areas. School creation, supporting education requirements, college payments,shelter support, food support, job creation, financial support for structures and buildings in need. In so many areas it's necessary to throw hygiene and self care education. Financial support to those who has potential but no money to move forward for it's particular requirements. Veteran support. Supporting orphanages and charity support for the families indirectly in different events. And so many more  .. . 

According to the money all kind of big and small charities can be done. How the person can support themselves ? It's all about management and balancing everything.

What is a "Life of Charity". I have seen people given instructions on charity that reflects more their benefit than the givers circumstances. Especially is this true of some that bring with them a religious title. The bible says at 1Tim 5:8 "Certainly if anyone does not provide for those who are his own, and especially for those who are members of his household, he has disowned the faith and is worse than a person without faith.