The app is very nice and useful. UI is user friendly. This apps lets you measure the correct dimensions of the things which can be placed over the phone screen. Things which can't be placed over the phon screen can't be measured. To overcome this following can come handy: Use camera (not photo or picture) for that. While camera will be showing the things, it can be marked and measured. (Although accuracy will not be 100%)
When you open it , it may looks inaccurate. But you can adjust it to fit your phone. Go and click calibration and bring your real ruler and put it on the phone and compare and adjust it. Push or pull your screen with finger and save. After then, it is very useful app to me. I love this.
Only goes as far as your screen... handy for small things, but if you need to measure something and you forgot a tape, choice is use this 16 times in a row and hope you lined up evenly or spend time going to the nearest construction store for a real tape...
Works perfectly on my Galaxy 7 Active. Ruler is, of course, limited by screen size, so if that's what you want to measure, I don't know how that could be improved.
People complaining are so stupid. Obviously the ruler is the size of your phone's screen...
I think the app would be improved with a snap-to-gradient feature that could be toggled on or off. Otherwise it works well for what it is, interface was intuitive for me.