Discussions

Because without it, "this" (the bullet, I presume, in your case), by default, is the object that the gameOver method would be executed on. But, the method is in your Space class and belongs to instances of the Space class. "public" just means you can call the method on an instance of the class from another class. From another class, you need to specify which instance of the class you are calling the method on, noting that you can create multiple inst

There are two ways to set colours. One way is what your font colour is using, which is <Code Omitted>Greenfoot provides several existed colours like Yellow, White, Red, Pink. You can find these colours on Greenfoot Documentation. Another ways is you make a colour. The method is <Code Omitted>or <Code Omitted>int a, int b, int c make up the RGB (red, green, blue) code and int d determines the transparency (0 is transpartent and 1 is opaque Hope this helps

Please refer to this page of the Java tutorials.

hi pple i figure out the error

For best help results, please show the current complete class and copy/paste the entire error output created from that code.

Too vague and general and lacking code. Please provide relevant class codes and point to what you tried where you are having issues.

One possibility, maybe, is to use mouse clicks to manually feed the cat. It is not necessary to retain a reference to the intersecting pizza or to pass it to the eatPizza method. You could simply have:

Example use of ask: <Code Omitted>

It is just a new variable used to control how many times the loop is executed -- a loop-counter.

Add: <Code Omitted>within the while loop. That should be good for around 20 milliseconds.

I am not really sure that synchronized needed to be used here in the Explosion class. When a method is declared to be synchronized, two or more different threads cannot simultaneously execute the method. One would be forced to wait until another has finished its execution of it. This is, however, most probably beyond the scope of what you should be concerned with at this point.

The images field is declared to hold an array of GreenfootImage objects. Line 6 creates an array of length IMAGE_COUNT and assigns it to the field. The for loop says to count up to that number of images (the count, held in 'i' will be used to point to a particular image in the array, as an index). When you see square brackets like that in any java code, then an array is being dealt with.

The final keyword is used to indicate that the value or object assignment is not allowed to change. The assigned value is a constant or the object is permanently assigned. If an attempt is made to make a re-assignment, a compilation error will ensue.

It take a vector (a direction and a magnitude, "length"), and converts it to the distances they make along the x and y axes to get to the same end-point.

The move method of the Actor class requires an int value in the parentheses. See here.