MITAppInventor
Getting started with MIT AppInventor

MIT App Inventor is a no-code app development platform that lets you develop applications for Android phones without any prior experience of coding using a web browser. You can test your app on your Android phone or on the emulator. Also, it stores your projects to have a track of them. You can sign-up on App Inventor Website and can start building the app from its drag and drop feature. It has also some detailed tutorials to help you in getting started.