import java.awt.*;
import java.awt.event.*;
import javax.swing.*;public class AppGraphInOut {
public static void main(String[] args){
new AppFrame();
}
}class AppFrame extends JFrame{
JTextField in = new JTextField(10);
JButton btn = new JButton("aa");
JLabel out = new JLabel("aaaa");
public AppFrame(){
setLayout(new FlowLayout());
getContentPane().add(in);
getContentPane().add(btn);
getContentPane().add(out);
btn.addActionListener(new BtnActionAdapter());
setSize(400,100);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setVisible(true);
}
class BtnActionAdapter implements ActionListener{
public void actionPerformed(ActionEvent e){
String s = in.getText();
double d = Double.parseDouble(s);
double sq = d*d;
out.setText(d+"的平方是:"+sq);
}
}
}
请问一下,btn.addActionListener(new BtnActionAdapter());里的new BtnActionAdapter()的actionperformed方法是自动执行吗?不需要调用吗?
import java.awt.event.*;
import javax.swing.*;public class AppGraphInOut {
public static void main(String[] args){
new AppFrame();
}
}class AppFrame extends JFrame{
JTextField in = new JTextField(10);
JButton btn = new JButton("aa");
JLabel out = new JLabel("aaaa");
public AppFrame(){
setLayout(new FlowLayout());
getContentPane().add(in);
getContentPane().add(btn);
getContentPane().add(out);
btn.addActionListener(new BtnActionAdapter());
setSize(400,100);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setVisible(true);
}
class BtnActionAdapter implements ActionListener{
public void actionPerformed(ActionEvent e){
String s = in.getText();
double d = Double.parseDouble(s);
double sq = d*d;
out.setText(d+"的平方是:"+sq);
}
}
}
请问一下,btn.addActionListener(new BtnActionAdapter());里的new BtnActionAdapter()的actionperformed方法是自动执行吗?不需要调用吗?
解决方案 »
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