Java でマウス リスナーを作成する

package delftstack;

import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Label;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

// The main class implements the MouseListener interface
public class Mouse_Listener implements MouseListener {
  // create two labels one frame and one string
  Label label1, label2;
  Frame Demo_Frame;
  String event_invo;

  // Constructor
  Mouse_Listener() {
    Demo_Frame = new Frame("The Mouse Listener");
    label1 = new Label("This is demo for the mouse listener events\n", Label.CENTER);
    label2 = new Label();

    // set the frame layout as flowlayout
    Demo_Frame.setLayout(new FlowLayout());

    // add labels to the frame
    Demo_Frame.add(label1);
    Demo_Frame.add(label2);

    // Register the created class Mouse_Listener to catch as well as respond to the mouse events,
    Demo_Frame.addMouseListener(this);

    // set the size of frame 450x300
    Demo_Frame.setSize(450, 300);

    // visibility of the frame will be true
    Demo_Frame.setVisible(true);
  }
  // mouseClicked method
  public void mouseClicked(MouseEvent ev) {
    event_invo += "     The mouse button was clicked";
    // set the text of label 2 as even_invo
    label2.setText(event_invo);
    // visibility will be true
    Demo_Frame.setVisible(true);
  }
  // mouseEntered method
  public void mouseEntered(MouseEvent ev) {
    // when mouse enters the window
    label2.setText("The mouse has entered the window");
    // visibility will be true
    Demo_Frame.setVisible(true);
  }
  // mouseExited method
  public void mouseExited(MouseEvent ev) {
    // when the mouse leaves the window
    label2.setText("Mouse has left the window");
    // visibility as true
    Demo_Frame.setVisible(true);
  }
  // mousePressed method
  public void mousePressed(MouseEvent ev) {
    // when the mouse is pressed
    label2.setText("Mouse button is pressed");
    // set the visibility as true
    Demo_Frame.setVisible(true);
  }
  // mouseReleased method
  public void mouseReleased(MouseEvent ev) {
    // set the string event_invo
    event_invo = "The mouse button is released    ";
    label2.setText(event_invo);
    // visibility as true
    Demo_Frame.setVisible(true);
  }
  // main method
  public static void main(String args[]) {
    new Mouse_Listener();
  }
}

package delftstack;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Mouse_Listener {
  private JFrame Demo_Frame;
  private JLabel Label_One;
  private JLabel Label_Two;
  private JPanel Control_Panel;

  public Mouse_Listener() {
    Create_GUI();
  }
  public static void main(String[] args) {
    Mouse_Listener MouseListenerDemo = new Mouse_Listener();
    MouseListenerDemo.Show_Mouse_Listener();
  }
  private void Create_GUI() {
    Demo_Frame = new JFrame("Java SWING With MouseListener");
    Demo_Frame.setSize(400, 400);
    Demo_Frame.setLayout(new GridLayout(3, 3));

    Label_One = new JLabel("", JLabel.CENTER);
    Label_Two = new JLabel("", JLabel.CENTER);
    Label_Two.setSize(350, 350);

    Demo_Frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent windowEvent) {
        System.exit(0);
      }
    });
    Control_Panel = new JPanel();
    Control_Panel.setLayout(new FlowLayout());

    Demo_Frame.add(Label_One);
    Demo_Frame.add(Control_Panel);
    Demo_Frame.add(Label_Two);
    Demo_Frame.setVisible(true);
  }
  private void Show_Mouse_Listener() {
    Label_One.setText("X Y Points for MouseListener");

    JPanel Demo_Panel = new JPanel();
    Demo_Panel.setBackground(Color.green);
    Demo_Panel.setLayout(new FlowLayout());
    Demo_Panel.addMouseListener(new CustomMouseListener());

    JLabel Msg_Label = new JLabel("Welcome to Delftstack.com", JLabel.CENTER);
    Demo_Panel.add(Msg_Label);

    Msg_Label.addMouseListener(new CustomMouseListener());
    Demo_Panel.add(Msg_Label);

    Control_Panel.add(Demo_Panel);
    Demo_Frame.setVisible(true);
  }
  class CustomMouseListener implements MouseListener {
    public void mouseClicked(MouseEvent e) {
      Label_Two.setText("Mouse Clicked: (" + e.getX() + ", " + e.getY() + ")");
    }
    public void mousePressed(MouseEvent e) {}
    public void mouseReleased(MouseEvent e) {}
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e) {}
  }
}