我的代码中的问题是，我试图编写一个程序，当您单击网格中的单元格时，该单元格内应出现一个圆圈。我很好。但是，当您第二次单击时，圆圈应消失。我不知道该怎么做。
我尝试用鼠标按下的已实现方法将圆形重绘为与背景相同的颜色，但这并不是很有效。当您按下它时它只会“消失”，但是我希望它在单击时消失。
我把它写成鼠标按下的，因为我不知道如何在鼠标点击的方法中使用它。
这是我的代码：
import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseEvent;
/**
* In this program, when user clicks a square, a circle appears until the user clicks it again.
*/
public class DD_GridFiller extends JFrame {
private int gridRows;
private int gridColumns;
private Color[][] circleColor; //color of circles
private Color lineColor; //color of lines
/**
* constructor
*/
public DD_GridFiller() {
setTitle("My Grid Filler");
setSize(600,600);
setLayout(new GridLayout(4,4));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
circleColor = new Color[4][4]; //stores the colors in arrays
gridRows = 4;
gridColumns = 4;
lineColor = Color.RED;
setPreferredSize( new Dimension(90*4, 90*4) );
setBackground(Color.BLACK); // set the background color for this panel.
addMouseListener(new MouseListener());
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int top, left; // position for top left corner of the window
left = ( screenSize.width - getWidth() ) / 2;
top = ( screenSize.height - getHeight() ) / 2;
setLocation(left,top);
setResizable(false);
setVisible(true);
pack();
}
public void paint(Graphics g) {
g.setColor(getBackground());
g.fillRect(0,0,getWidth(),getHeight());
int row, col;
double cellWidth = (double)getWidth() / gridColumns; //get cell width
double cellHeight = (double)getHeight() / gridRows; //get cell height
//create circles in every cell
for (row = 0; row < gridRows; row++) {
for (col = 0; col < gridColumns; col++) {
if (circleColor[row][col] != null) {
int x1 = (int)(col*cellWidth);
int y1 = (int)(row*cellHeight);
g.setColor(circleColor[row][col]);
g.fillOval(x1-2, y1-2, 23*4, 23*4);
}
}
}
//CREATES THE LINES
if (lineColor != null) {
g.setColor(lineColor);
for (row = 1; row < gridRows; row++) {
int y = (int)(row*cellHeight);
g.drawLine(0,y,getWidth(),y);
}
for (col = 1; col < gridRows; col++) {
int x = (int)(col*cellWidth);
g.drawLine(x,0,x,getHeight());
}
}
}
/**
* Finds the row
* @param pixelY location on x-axis
* @return rows
*/
private int findRow(int pixelY) {
return (int)(((double)pixelY)/getHeight()*gridRows);
}
/**
* Finds the column
* @param pixelX location of y-axis
* @return columns
*/
private int findColumn(int pixelX) {
return (int)(((double)pixelX)/getWidth()* gridColumns);
}
private class MouseListener implements java.awt.event.MouseListener {
@Override
public void mouseClicked(MouseEvent e) {
int row, col; // the row and column in the grid of squares where the user clicked.
row = findRow( e.getY() ); col = findColumn( e.getX() ); //find the location of cells clicked
circleColor[row][col] = new Color(0,223,197);
repaint(); // redraw the panel by calling the paintComponent method.
}
@Override
public void mousePressed(MouseEvent e) {
int row, col; // the row and column in the grid of squares where the user clicked.
row = findRow( e.getY() ); col = findColumn( e.getX() ); //find the location of cells clicked
circleColor[row][col] = new Color(0);
repaint(); // redraw the panel by calling the paintComponent method.
}
@Override public void mouseReleased(MouseEvent e) { }
@Override public void mouseEntered(MouseEvent e) { }
@Override public void mouseExited(MouseEvent e) { }
}
public static void main (String[] args) {
new DD_GridFiller();
}
}
最佳答案
您的问题是mousePressed一直将您的颜色设置为黑色。即使您检测到按下圆圈时颜色不是黑色，在mousePressed中也将其再次设置为黑色，然后再次绘制了圆圈，如此循环。
实际上，解决方案非常简单：
删除mousePressed中的所有内容。我们不需要它，mouseClicked实际上已经是mousePressed + mouseReleased。
将此添加到mouseClicked方法中：
@Override
public void mouseClicked(MouseEvent e) {
int row, col; // the row and column in the grid of squares where the user clicked.
row = findRow( e.getY() ); col = findColumn( e.getX() ); //find the location of cells clicked
System.out.println("Cell color: " + circleColor[row][col]); //will let you see whats happening
if (circleColor[row][col] == null) {
circleColor[row][col] = new Color(0,223,197);
} else {
circleColor[row][col] = null;
}
repaint(); // redraw the panel by calling the paintComponent method.
}
我们正在做什么-最初我们所有的颜色都是空的（在您的代码中，mousePressed会将它们设置为RGB [0,0,0]，即黑色）。因此，当我们第一次单击该单元格并看到该单元格颜色为“空”（即它为空）时，我们将圆形颜色设置为新颜色并绘制了圆形。如果再次按下，则检测到“颜色”不再为“ null”，即该单元格内部有一个圆形-然后将其设置为null。
某些人可能不喜欢Colors的“ null”概念-如果要使用RGB [0，0，0]而不是null，只需将任何初始出现的null转换为RGB [0，0，0]，然后使用：
public void mouseClicked(MouseEvent e) {
...
//initial setup
if (circleColor[row][col] == null) {
circleColor[row][col] = new Color(0);
}
System.out.println("Cell color: " + circleColor[row][col]); //will let you see whats happening
if (circleColor[row][col].equals(Color.getHSBColor(0,0,0))) {
circleColor[row][col] = new Color(0,223,197);
} else {
circleColor[row][col] = new Color(0) ;
}
repaint(); // redraw the panel by calling the paintComponent method.
}