爲什麼這個監聽器不能檢測窗口關閉事件？

Question

我想通過WindowStateListener在單個Frame上收聽活動。

import java.awt.Frame; 
import java.awt.Label; 

import java.awt.event.WindowStateListener; 
import java.awt.event.WindowEvent; 

public class UserInterface implements WindowStateListener 
{ 
    public static void main(final String[] arguments) 
    { 
     UserInterface userInterface = new UserInterface(); 
    } 

    public UserInterface() 
    { 
     Frame frame = new Frame("Graphics Example"); 
     frame.addWindowStateListener(this); 
     frame.add(new Label("Hello, world!"); 
     frame.pack(); 
     frame.setVisible(true); 
    } 

    public void windowStateChanged(WindowEvent event) 
    { 
     System.out.println(event.paramString(); 
    } 
} 

它最適合最小化事件，但不能關閉事件。 WINDOW_CLOSING is definitely a valid WindowEvent value和it's definitely something that Frame can throw。那麼爲什麼它不被傳遞給windowStateChanged()？

Answer 1

WindowStateListeners未通知窗口關閉事件。他們只會被告知窗口狀態的變化，如圖標化或去圖標化。如果您想關閉事件，請實現WindowListener（或擴展WindowAdapter）。本教程將對其進行解釋http://download.oracle.com/javase/tutorial/uiswing/events/windowlistener.html。

Answer 2

您可以使用它。

frame.addWindowListener(new java.awt.event.WindowAdapter() 
{ 
public void windowClosing(WindowEvent winEv) 

}} 

---

這肯定會編譯。

class TestSnippet { 
    public static void main(Sring[] args) { 

     // START: copy/pasted snippet 
     frame.addWindowListener(new java.awt.event.WindowAdapter() 
     { 
     public void windowClosing(WindowEvent winEv) 

     }} 
     // END: copy/pasted snippet 
    } 
} 

（A路人注意事項）嗯，除了..

I:\proj\TestSnippet.java:7: ';' expected 
     public void windowClosing(WindowEvent winEv) 
                ^
I:\proj\TestSnippet.java:9: ')' expected 
     }} 
     ^
2 errors 

Tool completed with exit code 1