Question

Write a program that takes a positive integer n as input from the user and displays an n by n checkerboard. (Hint: your main method could do user input then call the constructor for your GUI with n as the argument.) For example, when n = 5, there are 25 alternating white and black squares inside a square boarder. The lower right corner of the overall pattern must be white. Make sure that adjacent squares are different colors regardless of whether n is even or odd. You may want to use un-editable TextField Objects in a GridPane and use CSS to set background colors.
Be sure to use javaFX components for this .

Answer 1

Answer: See the code below:

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package checkerboard;

import java.util.Scanner;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.ColumnConstraints;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.RowConstraints;
import javafx.stage.Stage;

/**
*
* Checkerboard class
*/
public class Checkerboard extends Application {
  
@Override
public void start(Stage primaryStage) {
int n; //number of cells in checker board
Scanner in = new Scanner(System.in);
System.out.println("Enter number of cells in checker board:");
n = in.nextInt(); //read number of cells
final int NROWS = n; //number of rows
final int NCOLUMNS = n; //number of columns
final int squareSize = 100; //size of one square
int color=0; //flag for color of square
  
GridPane root = new GridPane(); //creates grid pane
  
//fix columns and rows of grid pane
for (int i = 0; i < NCOLUMNS; i++) {
ColumnConstraints columnConstraints = new ColumnConstraints();
columnConstraints.setPercentWidth(100.0 / NCOLUMNS);
root.getColumnConstraints().add(columnConstraints);
}
for (int i = 0; i < NROWS; i++) {
RowConstraints rowConstraints = new RowConstraints();
rowConstraints.setPercentHeight(100.0 / NROWS);
root.getRowConstraints().add(rowConstraints);   
}
  
//add squares to pane
for(int row = 0;row < NROWS; row++)
{
for(int col = 0;col < NCOLUMNS; col++)
{
Label label = new Label();
label.setMinWidth(squareSize);
label.setMinHeight(squareSize);
if(color == 0)
label.setStyle("-fx-background-color:#FFFFFF;");
else
label.setStyle("-fx-background-color:#000000;");
root.add(label,row,col);
color = (color == 0 ? 1 : 0);              
}
}
  
Scene scene = new Scene(root, NROWS*squareSize, NCOLUMNS*squareSize);
  
primaryStage.setTitle("Checker Board");
primaryStage.setScene(scene);
primaryStage.show();
in.close();
}

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}

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Output:

Checker Board