I have code which will draw circles depending on where the user clicks, and then will draw lines connecting those circles. I want to have the color of the circles and lines be set as Black by default, but the user can type either r,b,g,l (red, blue,green,black) to set the color of the NEXT circle and lines being drawn. What would I have to put inside of my KeyTyped method? I have if/else statements set up for whenever the user enters r,b,g, or l.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Circle extends JPanel implements MouseListener, KeyListener, MouseMotionListener {
private List<Point> points;
public static void main(String[] args) {
EventQueue.invokeLater(() -> new Circle().buildAndDisplayGui());
}
public Circle() {
points = new ArrayList<>();
setPreferredSize(new Dimension(500, 500));
setBackground(Color.white);
addMouseListener(this);
}
private void buildAndDisplayGui() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(this);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
frame.addKeyListener(this);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.black);
int count = points.size();
for (int i = 0; i < count; i ) {
Point pt0 = points.get(i);
g.fillOval(pt0.x - 10, pt0.y - 11, 20, 20);
if (i > 0) {
Point pt1 = points.get(i - 1);
g.drawLine(pt1.x, pt1.y, pt0.x, pt0.y);
}
}
}
@Override
public void mouseClicked(MouseEvent e) {
//Prints the coordinates of the clicks
System.out.println("X: " e.getX() " Y: " e.getY());
Point pt = new Point(e.getX(), e.getY());
points.add(pt);
repaint();
}
@Override
public void mouseEntered(MouseEvent e) {
// Do nothing.
}
@Override
public void mouseExited(MouseEvent e) {
// Do nothing.
}
@Override
public void mousePressed(MouseEvent e) {
// Do nothing.
}
@Override
public void mouseReleased(MouseEvent e) {
// Do nothing.
}
@Override
public void mouseDragged(MouseEvent e) {
}
@Override
public void mouseMoved(MouseEvent e) {
}
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyChar() == 'r') {
//Sets the color of the next circle and lines to red
} else {
if (e.getKeyChar() == 'b') {
//Sets the color of the next circle and lines to blue
} else {
if (e.getKeyChar() == 'g') {
//Sets the color of the next circle and lines to green
} else {
if (e.getKeyChar() == 'l') {
//Sets the color of the next circle and lines to black
}
}
}
}
}
@Override
public void keyPressed(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
}
Current output:
Desired Output (If the user presses “r” after two mouse clicks and the does two more mouse clicks):
CodePudding user response：
Add a
Colorinstance variable toclass Circle. In the example, I called it "currentColor". I set it toColor.blackin the constructor.Save a
Colorwith each item inpoints. One way to do that is to have a parallel array. I don't like tightly coupled arrays, so I created a helper class in my example.
class PointAndColor {
Point thePoint;
Color theColor;
PointAndColor () {
theColor = Color.black;
thePoint = new Point (0,0);
}
PointAndColor (Point point, Color color) {
theColor = color;
thePoint = point;
}
Color getColor () { return theColor; }
Point getPoint () { return thePoint; }
}
I changed the generic type of the List of Points:
private List<PointAndColor> points;
private Color currentColor;
Example of saving the color with the point:
@Override
public void mouseClicked(MouseEvent e) {
//Prints the coordinates of the clicks
System.out.println("X: " e.getX() " Y: " e.getY());
Point pt = new Point(e.getX(), e.getY());
points.add (new PointAndColor (pt, currentColor));
repaint();
}
Set the current color in the
keyTypedmethod@Override public void keyTyped(KeyEvent e) { switch (e.getKeyChar()) { case 'r': currentColor = Color.red; break; case 'g': currentColor = Color.green; break; case 'b': currentColor = Color.blue; break; case 'l': currentColor = Color.black; break; default: break; } System.out.println ("Color set to " currentColor);}
Retrieve the
Colorwith thePoint:
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int count = points.size();
for (int i = 0; i < count; i ) {
Point pt0 = points.get(i).getPoint();
g.setColor (points.get(i).getColor());
g.fillOval(pt0.x - 10, pt0.y - 11, 20, 20);
if (i > 0) {
Point pt1 = points.get(i - 1).getPoint();
g.drawLine(pt1.x, pt1.y, pt0.x, pt0.y);
}
}
}