您好，我已经设法让我的按钮着色。现在我想编写一段代码，只允许在任何行或列中使用每种颜色的一个按钮。我试过这个但不能让我的私有(private) boolean 值工作。下面是我现在只想检查行的代码
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.sql.*;
public class Grid5 extends JFrame implements ActionListener
{
private ColourChooser paintBox = null;
public static final int ROW = 6;
public static final int COLUMN = 6;
private static Grid5 grid;
public static final String defaultName = "Black";
public JButton[][] buttons; //makes an array called buttons
public static void main(String[] args)// sets up a 6x6 grid
{
int rows = 6;
int cols = 6;
int size = 600;
Grid5 grid = new Grid5(rows, cols);
grid.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
grid.setPreferredSize(new Dimension(size, size));
grid.pack();
grid.setLocationRelativeTo(null);
grid.setVisible(true);
}
// main
public Grid5(int rows, int cols) // makes the 6x6 main grid a grid of JButtons
{
int rowSize = 6;
int colSize = 6;
int gridSize = 600;
buttons = new JButton[rowSize][colSize];
Container pane = getContentPane();
pane.setLayout(new GridLayout(rows, cols));
for(int j =0; j < rows; j++){
for (int i = 0; i < cols; i++) {
buttons[j][i] = new JButton("");
buttons[j][i].setOpaque(true);
buttons[j][i].setBackground(Color.BLACK);
buttons[j][i].setActionCommand(j + " " + i);
buttons[j][i].setName("Black");
buttons[j][i].addActionListener(this);
pane.add(buttons[j][i]);
}
}
} //end of grid constructor
public void actionPerformed(ActionEvent e)
{
JButton button = (JButton) e.getSource();
if ( paintBox != null && paintBox.isShowing())//stops more than one paintBox from opening
paintBox.dispose();
if( e.getSource() instanceof JButton){
((JButton)e.getSource()).setBackground(Color.BLACK);
}
int rows = 6;
int cols = 1;
int size = 300;
paintBox = new ColourChooser(grid, false, button);
paintBox.setPreferredSize(new Dimension(size/3, size));
paintBox.pack();
paintBox.setVisible(true);
}
public class ColourChooser extends JDialog
{
private JButton fillRed = new JButton("Red");
private JButton fillYellow = new JButton("Yellow");
private JButton fillBlue = new JButton("Blue");
private JButton fillGreen = new JButton("Green");
private JButton fillPurple = new JButton("Purple");
private JButton fillBrown = new JButton("Brown");
private JButton[] paintButton = {fillRed,fillYellow,fillBlue,fillGreen,fillPurple,fillBrown};
private Color[] colours = {Color.RED, Color.YELLOW, Color.BLUE, Color.GREEN, new Color(102, 0, 102), new Color(102, 51, 0)};
private JButton buttonPress;
private int buttonsLeftRow ;
private int buttonsLeftColumn ;
private int row,column;
public ColourChooser(final Grid5 frame, boolean isModal, JButton button)
{
buttonPress = button;
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(6, 1));
for (int i = 0; i < paintButton.length; i++) {
paintButton[i].setOpaque(true);
paintButton[i].addActionListener(buttonAction);
paintButton[i].setForeground(new Color(100,100,100));
paintButton[i].setBackground(colours[i]);
panel.add(paintButton[i]);
}
add(panel);
pack();
}
private ActionListener buttonAction = new ActionListener()
{
public void actionPerformed(ActionEvent a)
{
JButton fill = (JButton) a.getSource();
String colour = "Red";
if(fill == fillRed){
if(checkColoursRow(colour,row)){
buttonPress.setBackground(Color.RED);
buttonPress.setName("Red");
dispose();
}
}
colour = "Yellow";
if(fill == fillYellow){
if(checkColoursRow(colour,row)){
buttonPress.setBackground(Color.YELLOW);
buttonPress.setName("Yellow");
dispose();
}
}
colour = "Blue";
if(fill == fillBlue){
if(checkColoursRow(colour,row)){
buttonPress.setBackground(Color.BLUE);
buttonPress.setName("Blue");
dispose();
}
}
colour = "Green";
if(fill == fillGreen){
if(checkColoursRow(colour,row)){
buttonPress.setBackground(Color.GREEN);
buttonPress.setName("Green");
dispose();
}
}
colour = "Purple";
if(fill == fillPurple){
if(checkColoursRow(colour,row)){
buttonPress.setBackground(new Color(102, 0, 102));
buttonPress.setName("Purple");
dispose();
}
}
colour = "Brown";
if(fill == fillBrown){
if(checkColoursRow(colour,row)){
buttonPress.setBackground(new Color(102, 51, 0));
buttonPress.setName("Brown");
dispose();
}
}
}
};
private boolean checkColoursRow(String colour, int row){
buttonsLeftRow = 0;
buttonsLeftColumn = 0;
String command = buttonPress.getActionCommand();
String[] arrayInfo = command.split(" ");
row = Integer.parseInt(arrayInfo[0]);
column = Integer.parseInt(arrayInfo[1]);
for(String c : grid.getRow(row)){
if(c.equals(null)){
continue;
if(buttonPress.getName().equals(c)){
return true;
}
}
return false;
}
}
}
}
谢谢
最佳答案
您在构造函数的一个设置行中将 j 和 i 倒过来，因此它指的是尚未创建的按钮实例:
buttons[i][j].setActionCommand(j + " " + i);
^ ^
当我调换它们并测试它时，程序运行得很好。
关于java - 为什么我尝试使用 getActionCommand 时出现空指针异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9930141/