A handy APP that provides the following measurement tools:
Level, Compass: Open the Leveler in the APP and place the phone on the platform to measure the level of the platform and display the bearing.
Ruler: Open the Ruler in the APP, the phone will display the ticks of ruler. You can change measurement units (cm, inch) and measure the length of anything.
Protractor: Open the Protractor in the APP, this function will enable the camera, shoot the real object through the camera, and you can measure the angle of the object through the Protractor on the image.