java - 无法设法在两个类之间使用 ActionListener

Question

我尝试实现两个类，一个专用于界面，另一个专用于允许用户在其上绘制形状的 Canvas 。

所以基本上，让我们使用我的按钮之一，这是我的 Jbutton bCircle，我想在其中初始化匿名类中的操作。我只放了具体的一 block :

public class Application extends JFrame implements ActionListener {

    toolBar.add(Box.createHorizontalGlue());
    toolBar.add(Box.createVerticalGlue());
    toolBar.add(bSquare, toolBar.getComponentCount() - 1);
    toolBar.add(bCircle, toolBar.getComponentCount() - 1);
    bCircle.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent event){
        //Action ?????
    }
});
    toolBar.add(bRectangle, toolBar.getComponentCount() - 1);
    toolBar.add(bTriangle, toolBar.getComponentCount() - 1);
    toolBar.add(bErase, toolBar.getComponentCount() - 1);
    toolBar.setOrientation(SwingConstants.VERTICAL);
    container.add(toolBar, BorderLayout.WEST);
}

在另一个类中，这里是我希望 Jbutton bCircle 的选定状态在我单击 Canvas 时执行的操作:

public class DrawingCanvas extends JPanel implements MouseListener, MouseMotionListener {

    public void mousePressed(MouseEvent e) {
    // TODO Auto-generated method stub
        if(e.getSource() == bCircle) {
            shapes.add(new Circle(e.getX(),e.getY()));
        }
        repaint();
    }
}

shapes 是一个存储形状的 ArrayList，使 Canvas 更易于清洁，Circle 是一个仅包含圆形绘制的类。

最后，目的是让用户先点击代表四种形状的四个按钮，然后通过在 Canvas 上按下鼠标来绘制它们。但是我不知道如何链接这两个类，请帮助我，

提前致谢

P.S:我第二次更新的完整应用程序类(接口(interface)):

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.Box;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.SwingConstants;

public class Application extends JFrame implements ActionListener {

{
    //Set appearance Look & Feel for the window
try { javax.swing.UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
    } catch(Exception e) {
        e.printStackTrace();
    }
}

    private DrawingCanvas canvas = new DrawingCanvas();
    private JPanel container = new JPanel();
    private JPanel commandes = new JPanel();
    private JMenuBar menu = new JMenuBar();
    private JMenu newFile = new JMenu();
    private JMenu open = new JMenu(); 
    private JMenu save = new JMenu();
    private JFileChooser fileChooser;
    private JToolBar toolBar = new JToolBar();

    private JButton bSquare = new JButton("Square");
    private JButton bRectangle = new JButton("Rectangle");
    private JButton bCircle = new JButton("Circle");
    private JButton bTriangle = new JButton("Triangle");
    private JButton bErase = new JButton("CLEAR");

    //public static boolean bIsSelected = false;

    public Application(){

    this.setTitle("Animation");         
    this.setSize(579, 432); 
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setLocationRelativeTo(null);
    this.setVisible(true);

        container.setBackground(Color.white);
    container.setLayout(new BorderLayout());
    container.add(canvas, BorderLayout.CENTER);
    this.setContentPane(container);

    toolBar.add(Box.createHorizontalGlue());
        toolBar.add(Box.createVerticalGlue());
        toolBar.add(bSquare, toolBar.getComponentCount() - 1);
        toolBar.add(bCircle, toolBar.getComponentCount() - 1);

        bCircle.addActionListener(new SampleActionListener(canvas, new Circle()));

            toolBar.add(bRectangle, toolBar.getComponentCount() - 1);
        toolBar.add(bTriangle, toolBar.getComponentCount() - 1);
        toolBar.add(bErase, toolBar.getComponentCount() - 1);
        bErase.addActionListener(new ActionListener(){
              public void actionPerformed(ActionEvent erase){
                 canvas.getShapes().clear();
                 repaint();
              }
            });
        toolBar.setOrientation(SwingConstants.VERTICAL);
        container.add(toolBar, BorderLayout.WEST);

        menu.add(newFile);
        newFile.setIcon(new ImageIcon("src/images/new.png"));
        menu.add(open);
        open.setIcon(new ImageIcon("src/images/open.png"));
        menu.add(save);
        save.setIcon(new ImageIcon("src/images/save.png"));
        this.setJMenuBar(menu);  

      }  

    public class SampleActionListener implements ActionListener {

        private final DrawingCanvas canvas2;
        private final ShapeGenerator shapeGenerator;

        public SampleActionListener(DrawingCanvas canvas, ShapeGenerator shapeGenerator) {
            this.canvas2 = canvas;
            this.shapeGenerator = shapeGenerator;
        }

        public void actionPerformed(ActionEvent event) {
           this.canvas2.setShapeGenerator(shapeGenerator);
        }
    }
    @Override
    public void actionPerformed(ActionEvent arg0) {
        // TODO Auto-generated method stub

    }   

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Application App = new Application();

    }
}

这是 Canvas 的类，也是第二次上传:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.util.ArrayList;

import javax.swing.JPanel;



public class DrawingCanvas extends JPanel implements MouseListener {

private ArrayList<Shape> shapes = new ArrayList<>();
private Shape shapeUnderMouse = null;

public ArrayList<Shape> getShapes() {
    return shapes;
}

public void setShapes(ArrayList<Shape> shapes) {
    this.shapes = shapes;
}

public DrawingCanvas() {
    super();
    addMouseListener(this);
}

public void paint(Graphics g){
    for(int i = 0;i < shapes.size();i++){
        shapes.get(i).paint(g);
    }    
}


@Override
public void mouseClicked(MouseEvent e) {
    // TODO Auto-generated method stub

}

@Override
public void mouseEntered(MouseEvent arg0) {
    // TODO Auto-generated method stub

}

@Override
public void mouseExited(MouseEvent arg0) {
    // TODO Auto-generated method stub

}

public void addShape(Shape anyShape)
{
        shapes.add(anyShape);
}

@Override
public void mousePressed(MouseEvent e) {

    shapes.add(this.shapeGenerator.getGeneratedShape(e.getX(), e.getY()));
    repaint();
}
@Override
public void mouseReleased(MouseEvent arg0) {
    // TODO Auto-generated method stub

}

public void setShapeGenerator(ShapeGenerator shapeGenerator) {
    // TODO Auto-generated method stub

}

现在，类的形状:

import javax.swing.JPanel;

public class Shape extends JPanel{

protected int posX;
protected int posY;

/*public Shape(int posX, int posY) {
    super();
    this.posX = posX;
    this.posY = posY;
}*/

public int getPosX() {
    return posX;
}

public void setPosX(int posX) {
    this.posX = posX;
}

public int getPosY() {
    return posY;
}

public void setPosY(int posY) {
    this.posY = posY;
}

}

我的小圈类:

import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Ellipse2D.Float;

import javax.swing.JPanel;

public class Circle extends Shape implements ShapeGenerator{

/*public Circle(int posX, int posY) {
    super(posX, posY);
    // TODO Auto-generated constructor stub
}*/

public void paint(Graphics g){
    g.fillOval(posX,posY,40,40);
    g.setColor(Color.blue);
  } 

public Shape getGeneratedShape(int x, int y) {
    return new Ellipse2D.Float(x, y, 10, 10); //--> does not work, ask me to change       method type to a float
    return new Circle();
    }

}最后是接口(interface)，所有类都在单独的类中:
公共(public)接口(interface) ShapeGenerator {

Shape getGeneratedShape(int posX, int posY);

}

Answer 1

事实上，这很容易。不要使用匿名类。

例如，对于您的代码，您只需附加一个已定义的监听器。例如:

bCircle.addActionListener(new SampleActionListener(pan, new CircleShapeGenerator()));

这是实现 ActionListener 接口(interface)的 SampleActionListener

public class SampleActionListener implements ActionListener {

    private final DrawingCanvas canvas;
    private final ShapeGenerator shapeGenerator;

    public SampleActionListener(DrawingCanvas canvas, ShapeGenerator shapeGenerator) {
        this.canvas = canvas;
        this.shapeGenerator = shapeGenerator;
    }

    public void actionPerformed(ActionEvent event) {
       this.canvas.setShapeGenerator(shapeGenerator);
    }
}

这是 CircleShapeGenerator 类

public class CircleShapeGenerator implements ShapeGenerator {
    public Shape getGeneratedShape(int x, int y) {
        return new Ellipse2D.Float(x, y, 10, 10);
    }
}

和接口(interface) ShapeGenerator

public interface ShapeGenerator {
      Shape getGeneratedShape(int x, int y);
}

而且，如果您想在矩形按钮上添加 Action 监听器，现在真的很容易。创建这个类:

public class RectangleShapeGenerator implements ShapeGenerator {
     public Shape getGeneratedShape(int x, int y) {
       return new Rectangle2D.Float(x, y, 10, 10);
      }
}

在你的应用类中，添加以下代码

toolBar.add(bRectangle, toolBar.getComponentCount() - 1);
bRectangle.addActionListerner(pan, new RectangleShapeGenerator() )

对于在 DrawingCanvas 中绘制的方法，我认为您应该使用这样的代码:

for (Shape s : shapes) {
       Graphics2D g2 = (Graphics2D) g;
       g2.draw(s);
}

BR,帕图什

对不起我的英语，我知道它不是很完美......