Adding Seeds

1. •  Create a new package called item

   • Inside this package, add the following classes:

     • Item

     • Seed (extends Item)

     • CropSeed (extends Seed)

     • CornSeed (extendsCropSeed) and PotatoSeed (extends CropSeed)
       
       

Abstract Classes

1. • • All of these classes except for CornSeed and PotatoSeed should be abstract.  You'll find it's a common pattern that all of your classes that aren't at the "bottom" of a hierarchy are abstract.
       
       

Item and Subclasses

1. • Since we're farther into this project, these instructions are going to start being a little higher level and vague on purpose.  Good luck, young coder.  

   • You'll need to create an image variable in Item and set the image in the appropriate subclasses

CHECKPOINT
Run your code and see...

• Your program should be displaying an itembar at the bottom of the screen

Selection

1. • In class ItemBar

     • Create an integer called selectedIndex, and start it at -1.  We'll use the code -1 to mean "no item selected."

     • Create accessor method hasSelectedItem().  Return false if selectedIndex is out of bounds.

     • Create accessor method getSelectedItem().  Return null if the there is no selected Item, using the method you just wrote.

     • Write a method called clearSelection() that sets selectedIndex to -1.

   • In class Item

     • Modify the render() method to take selectedIndex as an additional parameter.   If the index equals selectedIndex, have it draw a white box around itself.

Hotkeys

1. • In class ItemBar, write a keyPressed() method and have it called by Game's keyPress method.

   • Manage keypress events for 1-9.  Note that is a clever way to do this using math if you observe the values of KEY_ONE to KEY_NINE.  Remember that we’re off by one.

     • Warning -  If you are being clever and using the key's ID value and some math, you'll want to be careful here to *only* process keys that correspond to an appropriate index.  We don't want to translate space bar into an index position.

   • If you select a new key, change the selection to that key

   • If you select the same key, clear the selection

   • If you select an invalid key, clear the selection

CHECKPOINT
Run your code and see...

• Pressing different keys should allow you to change which key is currently selected, as well as unselecting any item by choosing it twice.

Game Container

1. • In a moment, we'll be adding coding code to change the cursor based on the item that is selected.  To do so, we'll need access to the GameContainer in a few different parts of our program.

   • By default, Slick 2D limits which methods access to this variable.  Since Game is a singleton, we'll make a public static reference to it that we can use in other parts of our program.

   • In the Game class, declare and assign a public static variable for gc.

SetCursor

1. • In class ItemBar, write a method:

     • public void setCursor()

       • If it does not have a selected item, set the default cursor

       • Otherwise, set the cursor to the image of the selected item and scale it to 32 by 32.

       • This needs to be in a try catch to handle the Exception.

       • Since this code is a bit clunky, I've provided it on this page as a reference.

CHECKPOINT
Run your code and see...

• When you have selected an item, it now appears as the cursor! Shiny!

Making Crops

1. • In the CropSeed class, create an abstract method called makeCrop()

   • In the CornSeed class, implement this by returning a new Corn() object.  Repeat this process for the PotatoSeed class.

Adding Parameters

1. • Look through World, Cell, and Terrain.  Each method that deals with "mousePressed" or "clicked" needs to take an Item as a parameter.   As usual, we'll have World call Cell which calls Terrain.

   • In your Game class, call the World's mousePressed method with getSelectedItem() as a parameter.

   • In the World class, make cells, entities, inBounds(), and addEntity() static.

     • We're only okay with using static here because World is a singleton. 

     • We're going to allow objects to directly add Entities to World, and do not want to have to pass the World everywhere.

Planting In Dirt

1. • We're finally there .  Write code in Dirt's click method to bring it together.

     • First, check if three conditions are met.

       • Is there soil?

       • Does the cell have an entity?

       • Is the item a cropSeed?

     • If so...

       • Store the Crop created by that Seed 

         • Note, you'll need to cast the Item to a CropSeed

       • Add the new crop to the world at the cell's location

     • Finally, make sure the other functionality of dirt only happen if you aren't planting a crop.

CHECKPOINT
Run your code and see...

• You can plant crops now!

• Seeds aren't expended when used.

Expiration

1. • Add an expired value to Item.  Follow the same process you did in Part Seven to remove expired entities, but with items this time.

   • Rather than having World manage it, we'll put our cleanup() method in ItemBar.  Just make sure it's being called by the Game class.

     • If the item you remove is the selected index:

       • Set selectedIndex to -1

       • Call setCursor()

     • As always, makes sure you don't skip items in your removal code.

   • Add a public method called expire() which sets expired to true

   • In the Dirt class, mark the passed item as expired when creating a crop.

CHECKPOINT
Run your code and see...

• Seeds are removed from your inventory when clicked