Animation Workshop. Support Files. Beginner CODING CHALLENGE - BEGINNER

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1 Animation Workshop Support Files Greenfoot Application: Greenfoot.org/download Greenfoot Reference: Greenfoot.org/files/javadoc/Greenfoot/package-summary Template: Scholastic.com/samsungacademy/resources/animation.zip Beginner Instructions: Before we start, we will gather everything needed for this exercise. Make sure you have downloaded Greenfoot from the provided link. Once Greenfoot is downloaded and installed, download the template file provided in the URL. The template file includes everything needed to complete this exercise. Once the template is opened, we are ready to start. Double-click on the section named AnimatedWorld on the right-hand side of the screen. A window will pop up with java code. Carefully read through the comments and look for the line that sets the size of the world. Currently the size is set to 400x400. Change it to be 800 pixels wide and 400 pixels high. Again, by reading the comments, look for the line of code that adds an actor to the screen. Change the number so that the x-location is 400 and the y-location is 100. Once the bird is in the correct starting location then it is time to move on.

2 Open the Bird class on the right-hand side of the screen. Once opened look for the act method. The act method is the heart of the Bird class. This method runs continuously, making it the perfect candidate for dealing with animation, movements, and keyboard events. In the act method, you will see a call to the flyright method. Look at the flyright method and study it. You will see a call to the setlocation method. The setlocation method takes in an x-coordinate and a y-coordinate and moves the character to that location. The way the fly method works is by grabbing the current x-position and adding a variable called speed to it. It grabs the y-coordinate and sets it to the current y-position. If you run the program now, you will see that the bird does not move. This is because the speed is set to 0. Find the speed variable in the Bird object and set it to any number greater than zero. If you run it now you should see your character move to the other side of the screen and stop. Now we are going to work on getting the bird to fly back and forth left to right. First look for the flyleft method. This function will work the same as the flyright method but instead of increasing the Bird s x-position, it will decrease the x-position by the speed. Using the code from the flyright method, create the flyleft method. Test it by removing the flyright method from act and adding the flyleft. The program and your bird should now fly left. As it currently stands, the bird stops when it reaches an edge. We want our bird to have a concept of direction. Look for a method called move. We are going to use this method to control the

3 movement of our bird. The move method checks to see if our direction variable is set to the value r and if it is equal to r then it calls the flyright method. Add another if statement that checks if the direction is set to l (for left). If it is correctly set it should call the flyleft method. Go to the act method and replace the flyleft method with move. The Bird should now move right. Now we want to make our bird change direction when it reaches the edge of the screen. We have two pre-built functions that check if our bird has reached an edge, isrightedge and isleftedge. Look for the directleft and directright methods. These two methods are responsible for changing the direction of the bird. In the checkdirection method we currently have a conditional that checks to see if the bird is on the right edge, and if it is, it changes the direction. Add another conditional to checkdirection to handle the changing of direction when the bird is on the left edge of the screen. To complete the process, add the checkdirection method to the act method. If you run the application, the bird should move from left to right. You probably noticed that something was not right. Our bird still faced right, even when the

4 direction was changed to left. To fix this we need to flip our character in the directright and directleft methods. Use the getimage method, provided by Greenfoot, to grab the image and call mirrorhorizontally on the image. Run the application, the bird should turn every time it reaches an edge. The final thing we will want to complete in this section is to get the bird to move up and down. Look for the checkkeyboardmovement method. In this method, you will see an empty conditional that checks to see if the down key has been pressed. Add another conditional to check for the up key. Inside each of them call the moveup and movedown methods already provided depending on which key is pressed. If you run the program now, you will see that you can move the bird vertically. Additional Notes Mistakes happen! The best programmers know that mistakes are part of the process. Don t hesitate to try something

5 new and don t get upset when you mess up. Check your resources! Don t be afraid to look things up. Use documentation, Stackoverflow, and Google to see if you can figure out the answer to a problem before you ask someone else. Feeling stuck? Double-check your dependencies, look for typos, give your mom a call. Often, just a few minutes away from a problem is all you need in order to solve it.