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Hello Purr Worksheet


1.    App Inventor has two main windows. What are they and what do they do?


The Component Designer runs in the browser window and this allows you to select components for your app and specify their properties.  This is GUI Builder, a graphical use emulator.  The Blocks Editor allows you to create behaviors for the components.

2. Testing and Running an App


a. How do you test an app while you're developing it?

            You can test your app on your phone or on the emulator as you are developing it.  You can choose to connect or not connect the device. 


b. How can you use your app when you're not connected to the computer?

            Package the app and download it to your phone or use it on the emulator.


c. What if you didn't have a phone, but wanted to program some apps. Could you? How?

            Yes, you would just use the app inventor program and test them on the emulator.


3. Its a good idea to rename components in the Component Designer, different from their default names. Why is this important?


            In component designer give descriptive names and a suffix with the component type.  That way when you get to the blocks editor you will know exactly what you are looking for. 

4. For the HelloPurr app, name the:


·      visual components:            The kitty button- property/image

·      non-visual components: properties:            Kitty sound- knows to play sound clip and vibrate action

·      events:                        when—kitty button clicks—play sound

§  button click—user event

§  sms event—text answers

§  web events—data comes from web

·      event-handlers:            An app and its behaviors is a set of event handlers.  And event and its response; a response is a sequence of function calls—e.g. sound play

·      calls to functions:            The information a function needs to do its job.


5.  In an app Inventor app:


a.     What is a component? 

Components are the elements you combine to create apps, like ingredients in a recipe.



b.     What is a property?

Properties are details about each component that you can change.


c.      What is an event?

An event is a response and a sequence of functions.


d.     What is an event-handler?

An event-handler is the information a function needs to do its jobs


e.      What is a "function call"?

A function call is what happens in the app.



6. One function call in Hello Purr required arguments (also known as parameters). Which function is it and what is the parameter?


            The function is the sound and the vibrate component.  The parameters are that when the phone is touch it meows and when it shakes it vibrates.



Anica Chavez,
Feb 12, 2012, 11:03 PM