I have been looking for a long time for a good android app that would allow me to edit equations, and get the latex code of it, but I haven´t found nothing really good, untill now ;-)
The first big step was my script smart note. It makes a great work in recognizing a handwriteen equation, and allos to export the latex code to a tex file.
But, in order to use it to write equations for a blog (or paper) I rather need to get the latex code writen to the wallpaper. For that purpose I begun writing an small app myself that imported the equations of that program. Althought my script makes a great work it doesn't allways recognizes things as you wan, so I decided to make a full equation's editor that can modify the imported equations, and ,of course, make an equation from zero. I have added symbols for most usual latex symbols, and also for the unsual. As far as I know the app is the most complete latex editor on the google play. It has a lot of symbols, and you have lot of flexibility to rearrange them to meet your preferences.
But I didn't stop there. In a typical use one needs to write some equations once and again, or variants of them, and it is pretty stupid to write them from scratch every time. To ride with that the app allows to save the latex code of the equations, together with additional information that allows to search them, in a database so one can construct it´s own equation's agend.
Once you have an equation you have buttons that copy the equation to the clipboard so you only need to paste them into the destination. It even wraps them with the tags corresponding to blogspot (if you use matjax), wordpress, or forums that are latex enabled (there is a button for every purpose).
If you have a note device (phablet, or even better, tablet) you can use the multiwindow features and use my app side by side with a document reader from wich you are actually copiying the equations, or a web navigator, or the blogspot/wordpress apps, or whatever you need, so you are far more productive.
I have made two versions of the app. The basic one, that is free (and withouth google adds by now) contains all the mentioned functionality. It is available at Google Play since now here
Beeing a blogger I have made it to make easy the most usual tasks of a scientific (mainly a physic) blogger, but It also makes a great work to write equations for a paper. As far as I know I honestly think that it is by far the best, and most complete equation editor in the android market, and, althought I don't know all the equations editors available, I think that even in windows there is nothing as complete and easy to use. But, of course, it may be because I have made it and I know how to use it, maybe others don't agree. In any case I hope you kike it, and find it usefull :).