#在我發佈的問題中,在此我無法理解第1行和第2行提到的代碼,因爲我知道他們是他們用於設置這個按鈕的動作監聽器,但是對我來說最令人困惑的是,在第1行和第2行中,{JB1.addActionListener(this)}的語法在這裏是「this」的角色。 ..請告訴我們背後的基本內容。以及整個語法是如何工作的...詳細信息。 #Swing:動作監聽器的作用
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class frametest1_1 implements ActionListener
{
JLabel JL;
public frametest1_1()
{
//create a JFrame container
JFrame JF=new JFrame("A BUTTON");
//Frame Layout This is contained in Java .awt.*; "ON USING THIS OPTION OUR BUTTON AND OTHER COMPONENT ARE ADJUSTED IN THE FRAME AUTOMATICALLY"
JF.setLayout(new FlowLayout());
//set the size of the container
JF.setSize(200, 200);
//set visible
JF.setVisible(true);
//make button
JButton JB1=new JButton("FIRST");
JButton JB2=new JButton("SECOND");
//add button to the JFrame container
JF.add(JB1);
JF.add(JB2);
//Create and add Label to the JFrame container
JL=new JLabel("PRESS A BUTTON");
JF.add(JL);
//set action command :now this will help in determining that which button is presses, is it FIRST or SECOND
JB1.setActionCommand("one");
JB2.setActionCommand("two");
//The action responded is added to the actionlistener
JB1.addActionListener((ActionListener) this); // line 1
JB2.addActionListener((ActionListener) this); // line 2
}
public void actionPerformed(ActionEvent ae)
{
if(ae.getActionCommand().equals("one"))
JL.setText("First Button Pressed"); // to set text on the label
else
JL.setText("Second button Pressed"); // to set the text on the label
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new frametest1_1();
}
});
}
}
請學習Java命名約定並嚴格遵守。 – kleopatra 2012-07-24 11:40:19