How can I open and edit large text documents on my Android device? I have a Galaxy Tab 10.1, rooted, running Android 5.1, that I'd like to use for editing simple text files. By "text file", I mean they are plain text documents, with a .txt extension. I do not need to edit .doc, .pdf, odt, or any other format.

I have seen this answer, and I have also tried a couple different apps, such as Jota, Turbo Editor, and others. They work fine for very small documents, but I have one text document that is about 300kB, and they all slow down and crash when I try to edit this file. Other files I have that are not quite as large seem to slow down just about any text editor, so it seems pretty clear there is a correlation between how big a document is and whether or not an Android text editor can handle it.

I'm confused as to why this is such a hard thing to do. I have games that I play on my various devices that seem to reference much larger resources and require more processing and RAM, so why should a simple text document under a megabyte be hard to work with?

In any case, is there a way I can edit a plain text document up to 500kB in size on my tablet device?
I'd suggest using ES file Explorer. I has a editor built-in that works pretty well for txt files. I have also tested with a file that's more than 900kb and worked fine. 

Hope it helps!