Question

我正在学习和创建自定义JButton / Component。我充分利用了我所需要的东西，除了我不知道如何在我的ActionListners上调用actionPerformed。

代码：

package myProjects;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.*;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;

public class LukeButton extends JComponent{
    public static void main(String[] args){
        JFrame frame = new JFrame();
        frame.setTitle("Luke");
        frame.setSize(300, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        LukeButton lb = new LukeButton();
        lb.addActionListener(e->{
            System.out.println("Success");
        });
        frame.add(lb);

        frame.setVisible(true);
    }

private final ArrayList<ActionListener> listeners = new ArrayList<ActionListener>();

public LukeButton(){

}
public void addActionListener(ActionListener e){
    listeners.add(e);
}
public void paintComponent(Graphics g){

    super.paintComponent(g);

    Graphics2D g2 = (Graphics2D)g;
    Shape rec = new Rectangle2D.Float(10, 10, 60, 80);

    g2.setColor(Color.BLACK);
    g2.setStroke(new BasicStroke(5));
    g2.draw(rec);
    g2.setColor(Color.BLUE);
    g2.fill(rec);
}
}

是否有人知道如何致电＆＃34;听众＆＃34;单击按钮后的ArrayList？谢谢您抽出宝贵时间。

Answer 1

您需要遍历ActionListener的列表并调用他们的actionPerformed方法，例如......

protected void fireActionPerformed() {
    if (!listeners.isEmpty()) {

        ActionEvent evt = new ActionEvent(this, ActionEvent.ACTION_PERFORMED, "LukeButton");
        for (ActionListener listener : listeners) {
            listener.actionPerformed(evt);
        }

    }
}

现在，您需要定义可能触发ActionEvent发生的操作，鼠标单击，按键等，并在发生fireActionPerformed方法时调用

有关详细信息，请查看How to Write a Mouse Listener和How to Use Key Bindings

调用ActionEvent

1 个答案: