Hands-On Robotics Programming with C++

Main block

The main block inside App Inventor 2 is similar to a when loop, which indicates an action to carry out when something happens. The main block is always connected to an intermediate block. We cannot connect the final block directly to the main block. The main block consists of a drop-down menu from which we can choose between multiple components that are of the same type. For example, look at the following screenshot:

You can see that in a scenario where you have multiple buttons, you can choose a particular button from the drop-down list.