我正在尝试创建一个绘画程序，允许用户单击特定的工具并将其绘制在画布上。每个工具都应像Microsoft Paint一样工作，用户可以通过拖动和释放来绘制形状，然后自由移动它们。
但是，我无法使用当前的代码绘制。我不知道问题是由什么引起的，因为我单击画布时没有弹出任何消息，所以我不知道我的工具是否已正确实现。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.awt.geom.*;
public class guiInterface {
static int shapeCheck = 0;
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
// create a new JFrame, which is a top-level window
JFrame frame = new JFrame("Canvas Painter");
// Tell the frame that the application should exit when we close it
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//sets up a menu bar
JMenuBar menuBar = new JMenuBar();
frame.setJMenuBar(menuBar);
//setus up the file aspect of the menu bar
JMenu file = new JMenu("File");
menuBar.add(file);
//adds the items for the file aspect
JMenuItem newButton = new JMenuItem("New");
file.add(newButton);
JMenuItem delete = new JMenuItem("Delete");
file.add(delete);
JMenuItem quitButton = new JMenuItem("Quit");
file.add(quitButton);
//when clicked it will exit out of the program
quitButton.addActionListener(e -> System.exit(0));
//sets up the edit aspect of the menu bar
JMenu edit = new JMenu("Edit");
menuBar.add(edit);
//sets up the view aspect of the menu bar
JMenu view = new JMenu("View");
menuBar.add(view);
//adds the aspects to the view part of the program.
JMenuItem next = new JMenuItem("Next");
view.add(next);
JMenuItem previous = new JMenuItem("Previous");
view.add(previous);
//Left Hand Side tool pallette
//if possible add the toggle buttons to a group
JPanel buttons = new JPanel(new GridLayout(0, 1));
ButtonGroup group = new ButtonGroup();
JToggleButton select = new JToggleButton();
select.setIcon(new ImageIcon("C:\\Users\\HamzaHamid\\Desktop\\cs4470\\swing-examples\\HW1\\selectbutton.png"));
group.add(select);
JToggleButton line = new JToggleButton();
line.setIcon(new ImageIcon("C:\\Users\\HamzaHamid\\Desktop\\cs4470\\swing-examples\\HW1\\linebutton.png"));
group.add(line);
JToggleButton rectangle = new JToggleButton();
rectangle.setIcon(new ImageIcon("C:\\Users\\HamzaHamid\\Desktop\\cs4470\\swing-examples\\HW1\\rectanglebutton.png"));
group.add(rectangle);
JToggleButton oval = new JToggleButton();
oval.setIcon(new ImageIcon("C:\\Users\\HamzaHamid\\Desktop\\cs4470\\swing-examples\\HW1\\ovalbutton.png"));
group.add(oval);
JToggleButton pen = new JToggleButton();
pen.setIcon(new ImageIcon("C:\\Users\\HamzaHamid\\Desktop\\cs4470\\swing-examples\\HW1\\rectanglebutton.png"));
group.add(pen);
JToggleButton text = new JToggleButton();
text.setIcon(new ImageIcon("C:\\Users\\HamzaHamid\\Desktop\\cs4470\\swing-examples\\HW1\\textbutton.png"));
group.add(text);
//adds the button to a JPanel called buttons
buttons.add(select);
buttons.add(line);
buttons.add(rectangle);
buttons.add(oval);
buttons.add(pen);
buttons.add(text);
//main content area
//Container content = frame.getContentPane();
//content.setLayout(new BorderLayout());
final ContentArea canvas = new ContentArea(shapeCheck);
//content.add(canvas, BorderLayout.CENTER);
//status bar
JLabel status = new JLabel();
status.setText(" Status Bar");
//This creates actions when each specific button is clicked.
newButton.addActionListener(e -> status.setText(" New Button has been clicked"));
delete.addActionListener(e -> status.setText(" Delete Button has been clicked"));
next.addActionListener(e -> status.setText(" Next Button has been clicked"));
previous.addActionListener(e -> status.setText(" Previous Button has been clicked"));
select.addActionListener(e -> status.setText(" Select button has been clicked"));
line.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
status.setText(" Line button has been clicked");
shapeCheck = 1;
}
});
rectangle.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
status.setText(" Rectangle button has been clicked");
shapeCheck = 2;
}
});
oval.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
status.setText(" Ellipse button has been clicked");
shapeCheck = 3;
}
});
pen.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
status.setText(" Pen button has been clicked");
shapeCheck = 4;
}
});
text.addActionListener(e -> status.setText(" Text Button has been clicked"));
//Extra Credit
//Color chooser
JToggleButton color1 = new JToggleButton();
color1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Color newColor = JColorChooser.showDialog(null, "Choose", color1.getBackground());
if(newColor != null){
color1.setBackground(newColor);
}
}
});
//this pretty much says that a color has been chosen
color1.addActionListener(e -> status.setText(" Color 1 Button has been clicked"));
//adds the color button to the group
//which is then added to the buttons JPanel
group.add(color1);
buttons.add(color1);
//creates a pannel of the buttons, and other things
JPanel left = new JPanel(new BorderLayout());
left.add(buttons, BorderLayout.NORTH);
frame.add(left, BorderLayout.WEST);
frame.add(canvas, BorderLayout.EAST);
//frame.add(content, BorderLayout.EAST);
frame.add(status, BorderLayout.SOUTH);
// pack() causes the size of the frame to be set just large enough to contain its
// children; setVisible(true) puts it on the screen
frame.pack();
frame.setVisible(true);
}
}
//creates the content area and places it in the text area
class ContentArea extends JComponent {
int oldX = 0;
int oldY = 0;
int currentX = 0;
int currentY = 0;
ArrayList<Shape> variousShapes = new ArrayList<Shape>();
Shape theShape;
public ContentArea(int shapeCheck){
int shapeNum = shapeCheck;
setDoubleBuffered(false);
addMouseListener(new MouseAdapter(){
public void mousePressed(MouseEvent e){
oldX = e.getX();
oldY = e.getY();
currentX = oldX;
currentY = oldY;
repaint();
}
public void mouseReleased(MouseEvent e) {
switch(shapeCheck) {
case 1:
theShape = drawLine(oldX, oldY, currentX, currentY);
case 2:
theShape = drawRectangle(oldX, oldY, e.getX(), e.getY());
case 3:
theShape = drawEllipse(oldX, oldY, e.getX(), e.getY());
default:
theShape = null;
}
variousShapes.add(theShape);
oldX = 0;
oldY = 0;
currentY = 0;
currentX = 0;
repaint();
}
});
//if the mouse is pressed it sets the oldX & oldY
//coordinates as the mouses x & y coordinates
addMouseMotionListener(new MouseMotionAdapter(){
public void mouseDragged(MouseEvent e){
if (shapeCheck == 4) {
theShape = drawLine(oldX, oldY, currentX, currentY);
}
repaint();
}
});
}
public void paintComponent(Graphics g){
Graphics2D graphics1 = (Graphics2D) g;
super.paintComponent(g);
graphics1 = (Graphics2D) g;
graphics1.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
for (Shape s : variousShapes) {
graphics1.draw(s);
}
}
private Ellipse2D.Double drawEllipse (int x1, int y1, int x2, int y2) {
int x = Math.min(x1, x2);
int y = Math.min(y1, y2);
int width = Math.abs(x2 - x1);
int height = Math.abs(y2 - y1);
return new Ellipse2D.Double(x, y, width, height);
}
private Rectangle2D.Double drawRectangle (int x1, int y1, int x2, int y2) {
int x = Math.min(x1, x2);
int y = Math.min(y1, y2);
int width = Math.abs(x2 - x1);
int height = Math.abs(y2 - y1);
return new Rectangle2D.Double(x, y, width, height);
}
private Line2D.Double drawLine (int x1, int y1, int x2, int y2) {
return new Line2D.Double(x1, y1, x2, y2);
}
我发现了一些问题。首先，我认为您的画布不可见。通过以下方式将其添加到中心：
frame.add(canvas, BorderLayout.CENTER);
接下来，将shapeCheck传递给ContentArea构造函数。这是shapeCheck的副本，但ContentArea需要读取guiInterface.shapeCheck中的实际变量。
最后，您的switch语句需要break语句，否则它将始终落入default并设置theShape = null;
public void mouseReleased(MouseEvent e) {
switch (guiInterface.shapeCheck) {
case 1:
theShape = drawLine(oldX, oldY, e.getX(), e.getY());
break;
case 2:
theShape = drawRectangle(oldX, oldY, e.getX(), e.getY());
break;
case 3:
theShape = drawEllipse(oldX, oldY, e.getX(), e.getY());
break;
default:
theShape = null;
break;
}
if (null != theShape) {
variousShapes.add(theShape);
}
oldX = 0;
oldY = 0;
currentY = 0;
currentX = 0;
repaint();
}
以及绘图工具的修复程序：
addMouseMotionListener(new MouseMotionAdapter() {
public void mouseDragged(MouseEvent e) {
if (delete_me.shapeCheck == 4) {
variousShapes.add(drawLine(oldX, oldY, e.getX(), e.getY()));
oldX = e.getX();
oldY = e.getY();
repaint();
}
}
});