Introduction to Computer Science with Scratch and App Inventor

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Let’s see what our procedure looks like when it runs on a phone. To do this, we will need to start the Android emulator. Once your emulated phone is ready to go, you need to connect to it. You do this through the Blocks Editor by clicking on the Connect to Device button and choosing the emulator from the drop down list (there should only be one option). As the Block Editor connects to the emulator, the little phone icon will first turn yellow, and then green. When the phone icon is green, your Blocks editor is connected to your emulator and your app will show up on the simulated screen. Any changes you make to your app in App Inventor or the Blocks Editor will automatically show up in the emulator. Click on the New emulator button on the top of the screen. This will open a window telling you to be patient. Click OK and be patient Your emulated phone will fire up and initialize. When you see the middle screen, drag the green lock to “unlock” the phone. When you see the screen on the far right, your emulated phone is all ready to go! mbrace Game Development Workbook Page 42
Our mole shows up in the emulator, but he isn’t moving. What’s wrong? We need to call our MoveMole procedure – this is true of every procedure, you must call it when you want it to run. When do we want our MoveMole procedure to run? Every time our timer goes off. Where do you think we could find a block for the timer? On the My Blocks tab, there is a menu for MoleTimer. One of the blocks is when MoleTimer.Timer do. This block allows us to specify certain commands to run every time that the timer goes off. What do we want to do each time the timer goes off? We want to call our MoveMole function. To do this, we want to go to the My Definitions menu on the My Blocks tab. Our procedure shoes up in this menu, because it is a procedure that we defined. We will need the call MoveMole block This is what the code to call our function should look like. Now if you look at the emulator, the mole should be jumping around the screen. What should the next step in our project be? Right now, nothing happens if the user touches the mole. Let’s add onto our program so that when the user touches the mole, his/her score goes up by one. The steps for this process will be: 1) Create a variable called score to hold the user’s score (just like we did in the dinosaur game) 2) Add an element to the interface to display the current score 3) Add one to the value of score every time the user touches the mole To create a variable, we will use the def variable as block from the Definition menu in the Built-In tab. You will notice that when you drag this block into the program area, there is a yellow exclamation point in the block. This is because Blocks Editor wants you to give the variable an initial value. Let’s set the initial value to zero since the player will start the game with zero points. mbrace Game Development Workbook Page 43
Page 1 and 2: Introduction to Computer Science wi
Page 3 and 4: LESSON 1: Getting Started with Scra
Page 5 and 6: I decided to pick a dinosaur. You c
Page 7 and 8: The direction that your sprite move
Page 9 and 10: Let’s add some yellow wait blocks
Page 11 and 12: Changing the Background on the Stag
Page 13 and 14: To use an if block to control the m
Page 15 and 16: Costumes and Animation Now that you
Page 17 and 18: Other useful blocks are the say and
Page 19 and 20: ? Now we know how to tell when the
Page 21 and 22: Here is one script that works. To m
Page 23 and 24: After you create a variable, you wi
Page 25 and 26: Winning, Losing, and Game Play Our
Page 27 and 28: You might have noticed that when th
Page 29 and 30: Click the checkbox next to timer to
Page 31 and 32: Scratch Review Now you have built y
Page 33 and 34: App Inventor Interface The App Inve
Page 35 and 36: The first thing that we will do is
Page 37 and 38: To add the mole to our program, we
Page 39 and 40: Your Blocks Editor Screen should lo
Page 41: We know that our X and Y locations
Page 45 and 46: The last thing we need is the value
Page 47 and 48: Team Project Worksheet We have lear

Introduction to Computer Science with Scratch and App Inventor

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