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Learning MIT App Inventor: A Hands-On Guide to Building Your Own Android Apps by Mark Sherman, Derek Walter

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Summary

Component properties are variables that are built into a component. Setting a component property’s value in the Designer sets the starting value of that property. It can be changed as the app runs—by blocks, by the user, or both. Component properties are accessible with the green getter and setter blocks for that component, and they have global scope.

Event parameters are special variables that give you extra information about an event. Event parameter variables are valid only inside the event handler they belong to (meaning that they have limited scope). Each time the event runs, you might get different information in those parameters, which reflects the details of that one occurrence of the event. Event parameters use the orange getter ...

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