理解java的问题ActionListener - 执行（ActionEvent e）

Question

我必须为Fibonacci程序编写代码，该程序构建一个带有两个文本框和一个按钮的GUI。用户在文本框1中输入一个数字，然后单击该按钮，然后放置该数字的斐波纳契数。我在理解java的actionPerformed部分时遇到问题，并希望得到任何帮助。这是我的代码：有3个文件。

Fibonacci.java

public class Fibonacci{ 
    int Fib (int n){ 
     int in1=1,in2=1; 
     int sum=0;//initial value 
     int index=1; 
     while (index<n){ 
     sum=in1+in2;//sum=the sum of 2 values; 
     in1=in2;//in1 gets in2 
     in2=sum;//in2 gets sum 
     index++; //increment index 
     } 
    return sum; 
    } 
} 

FibonacciJPanel.java

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


public class FibonacciJPanel extends JPanel implements ActionListener 
{ private JTextField inField = new JTextField(15); //GUI components 
    private JTextField resultField = new JTextField(15); 
    private JLabel prompt1 = new JLabel("Input Fibonacci>>"); 
    private JLabel prompt2 = new JLabel("Conversion Result:"); 
    private JButton FibonacciButton = new JButton("Fibonacci of the input"); 
    private JPanel panelN = new JPanel();  //Panels 
    private JPanel panelC = new JPanel(); 
    private JPanel panelS = new JPanel(); 
    private Fibonacci F = new Fibonacci(); 



    public FibonacciJPanel()      //Set up user panel 
    { setLayout(new BorderLayout());    //User BorderLayout 
    panelN.setLayout(new BorderLayout()); 
    panelC.setLayout(new BorderLayout()); 
    panelS.setLayout(new BorderLayout()); 
    panelN.add("North", prompt1);    //Input elements 
    panelN.add("South", inField); 
    panelC.add("West", FibonacciButton);  //Control button 
    panelS.add("North", prompt2);    //Output elements 
    panelS.add("South", resultField); 
    add("North", panelN);      //Input at the top 
    add("Center", panelC);      //buttons in the center 
    add("South", panelS);      //Result at the bottom 
    FibonacciButton.addActionListener(this);   //Register with listeners 
    setSize(175,200); 
    } //FibonacciJPanel 



public void actionPerformed(ActionEvent e) 
    { 
String inputStr = inField.getText();  //user input 
     int userInput = Integer.parseInt(inputStr); //convert to integer 
     boolean result=false; 
    if (e.getSource() == FibonacciButton);   //Process and report 
    { 
      result = fc.sum(userInput); 
      resultField.setText("result"); 

    } //if 
    }//actionPerformed() 
} 

FibonacciJApplet.java

import javax.swing.*; 

public class FibonacciJApplet extends JApplet 
{ public void init() 
    { getContentPane().add(new FibonacciJPanel()); 
    } // init() 
} // Fibonacci class 

Answer 1

哟你不提什么是你不明白的。

基本上，当你添加一个按钮时，它知道如何触发事件，当你点击它到一个叫做Event Dispatcher Thread（EDT）的线程时。

每当你点击一个按钮，这个事件会通知到该按钮中注册的每一个“监听器”（他们正在监听的通知）

因此，一个简单的例子是：

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

class Click { 
    public static void main(String ... args) { 
     JButton clickMe = new JButton("Click Me"); 
     ActionListener aListener = new OneActionListener(); 
     clickMe.addActionListener(aListener); 
     JFrame frame = new JFrame(); 
     frame.add(clickMe); 
     frame.pack(); 
     frame.setVisible(true); 
    } 
} 
class OneActionListener implements ActionListener { 
    public void actionPerformed(ActionEvent e) { 
     System.out.printf("Clicked. Thread: %s, action: %s%n", 
      Thread.currentThread().getName(), 
      e.getActionCommand()); 
    } 
} 

这里你声明一个实现了ActionListener接口的类OneActionListener让我知道他可以处理事件的按钮（用actionPerformed方法）

我希望这个清楚一点这工作。