This app was mentioned in 3 comments, with an average of 1.33 upvotes
I played a little with Vernier's Graphical. It is free and is both droid and iphone available. With a few tweaks I could get a decent average value. It was a little clunky, but I was able to select sections of the a vs t graph and get a linear best fit that could be used for the average value. I thought about using it in my classes, but I am leaning towards tracker pro (like logger but free). I try to get my students set up to do the video analysis at home in addition to easier to collect lab data for in class. I think I tried one or two apps, graphical seemed the best to record the accelerometer data. You do not need to export it, and the few trials I ran worked pretty well to do a lab with low friction carts for Newton's 2nd Law. However, I found it easier to have students do video recordings and tackle it in Tracker outside of class time.
If you teach AP1 I got this app awhile back for frequency measurements. There may be good ones that are free, but this one is pretty nice. I wish it had a csv export function. However, it works well to do wave mechanics stuff and measuring the speed of sound with PVC piping.
https://play.google.com/store/apps/details?id=com.electronchaos.SpeedySpectrumAnalyzer&hl=en
I use Speedy Spectrum Analyzer to quickly find feedback, but I can't imagine using this to actually shape my sound.