draw method must be called on created apple

Question about the task

Snake (Part 4/20)

Games, Level 0, Lesson 1

Resolved

As far as i can see i am using the draw method on the created apple ..........

One of the game objects will be an apple. Create an Apple class and make it inherit the GameObject class.

To represent an apple on the playing field, you could paint cells containing apples any particular color. Or you could draw some apple-looking symbol in the cell. Let the Apple class store this symbol in the APPLE_SIGN variable.

Add a draw(Game) method to the Apple class: it will draw an apple on the playing field. To do this, in the draw(Game game) method, you need to call game.setCellValueEx(...).

Because the Apple class uses the Game and Color classes, these (and other) engine classes are located in the com.codegym.engine.cell package. To use them, the Apple class must include the following import statement: import com.codegym.engine.cell.*;

To see what an apple will look like, in the createGame() method, create an apple with coordinates (7, 7) and call its draw(Game) method.

Requirements:

There must be a public Apple class.
The Apple class must be a descendant of the GameObject class.
The Apple class must have one constructor with two int parameters (x and y), which uses the keyword super to call the base class's constructor with the x and y parameters.
The Apple class must have a private static final String APPLE_SIGN field that is initialized when it is declared. For example, you can use the UTF-16 symbol for an apple: "\uD83C\uDF4E".
The Apple class must have a public void draw(Game) method.
The draw(Game) method must call the setCellValueEx(int, int, Color, String, Color, int) method on a Game object with the following arguments: x, y, Color.NONE, APPLE_SIGN, <color of the apple>, 75. (Replace <color of the apple> with a color you like, for example, Color.GREEN).
The SnakeGame class's createGame() method must create a new apple (an instance of the Apple class) with coordinates (7, 7).
The draw(Game) method must be called on the created apple. Pass this to the method.
The Apple class must have a statement that imports the entire contents of the com.codegym.engine.cell package.

package com.codegym.games.snake; import com.codegym.engine.cell.*; public class SnakeGame extends Game { public static final int WIDTH = 15,HEIGHT = 15; @Override public void initialize(){ setScreenSize(WIDTH,HEIGHT); createGame(); } private void createGame(){ Apple apple = new Apple(7,7); apple.draw(this); drawScene(); } private void drawScene(){ for (int i = 0; i < WIDTH; i++) { for (int y = 0; y < HEIGHT; y++) { setCellColor(i, y, Color.PURPLE); } } } }

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Nithin

Level 35 , Hyderabad, India

16 July 2019, 03:56

solution

you need to call the drawscene method first i.e, you should create a gameboard first and then put an apple in it . But here you are first creating an apple and putting the gameboard on it :) . change it to:

private void createGame() {
        drawScene();
        Apple apple = new Apple(7, 7);
        apple.draw(this);

    }

Wouter Van Kerschaver

Level 6 , Oostende, Belgium

16 July 2019, 07:41

my god feel so stupid right now haha, thx !

Harrison Tran

Level 14 , Anaheim, United States

4 June 2020, 00:50

what is the key word "this" refer to in this code?

apple.draw(this);

and what is "Game" refer to in this code?

public void draw(Game game){
 game.setCellValueEx(x, y, Color.NONE, APPLE_SIGN, Color.RED, 75); // can someone explain this line of code for me?

thanks

Russell

Level 9 , Galmpton, Brixham , United Kingdom

30 September 2020, 12:19

So.. if im understanding correctly, I believe the "this" keyword refers to the gameboard created in your create game function (drawscene()) as it is an object with, at the time the new method is called, a 15 by 15 grid of tile objects. This informs the program to change the value of the cell at 7,7 (dead centre) to an apple symbol. which is why the game object needs to be passed in to the apple.draw() method. else the java program will be looking all over the place for cell 7,7 on a non-existant game board.

Wouter Van Kerschaver

Level 6 , Oostende, Belgium

15 July 2019, 16:30

Apple apple = new Apple(7,7); Game game = new Game(); apple.draw(this); ==> this code doesnt work as well