Java - 关闭 JFrame 窗口时的消息
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Java - Message when closing JFrame Window
提问by Matthew
I have a Java Program containing a class Applicationinheriting from JFrame.
我有一个 Java 程序，其中包含一个从 JFrame 继承的类应用程序。
I want to display a message which asks the user if he wants to exit the program upon clicking the X button at the top right of the window.
我想显示一条消息，询问用户是否要在单击窗口右上角的 X 按钮后退出程序。
This is my code so far:
到目前为止，这是我的代码：
I got this code from a tutorial I found online. I coded the WindowClosing event handler myself. However, I have trouble registering the window listener (addWindowListener). It is telling me that WindowAdapter is abstract and cannot be instantiated.
我从网上找到的教程中得到了这段代码。我自己编写了 WindowClosing 事件处理程序。但是，我无法注册窗口侦听器 (addWindowListener)。它告诉我 WindowAdapter 是抽象的，无法实例化。
How can I solve this problem please?
请问我该如何解决这个问题？
回答by Dan D.
Basically, you got it almost correct. There are a few things not put together correctly and a typo.
基本上，你几乎是正确的。有一些东西没有正确组合在一起，还有一个错字。
First remove your WindowClosingmethod (it's window, not Window)
Then replace your addWindowListener(new WindowAdapter());with the code below
首先删除你的WindowClosing方法（它是window，不是Window）然后用addWindowListener(new WindowAdapter());下面的代码替换你的
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
int confirmed = JOptionPane.showConfirmDialog(null,
"Are you sure you want to exit the program?", "Exit Program Message Box",
JOptionPane.YES_NO_OPTION);
if (confirmed == JOptionPane.YES_OPTION) {
dispose();
}
}
});
回答by Synester
i got this in two minutes coding....
我在两分钟内得到了这个编码....
First is set the j frame default closing event in Exit_on_close. Second create a class called "Window Closing Event Handler" and then call it in the i nit stage.
首先是在 Exit_on_close 中设置 j 帧默认关闭事件。其次创建一个名为“窗口关闭事件处理程序”的类，然后在初始化阶段调用它。
private void WindowClosingEventHandler(){ addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { int confirmed = JOptionPane.showConfirmDialog(null, "Are you sure you want to exit this application?", "Exit Program Message Box",JOptionPane.YES_NO_OPTION);
if (confirmed == JOptionPane.YES_OPTION) {
try{
String login=txtuserid.getText();
Connection conn = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/repair", "root", "");
Statement st = conn.createStatement();
String update = "UPDATE user set User_Status=0 where UserID='"+ login +"'";
st.executeUpdate(update);
dispose();
Login2 dialog = new Login2(new javax.swing.JFrame(), true);
dialog.setVisible(true);
}catch(SQLException | HeadlessException q){
JOptionPane.showMessageDialog(null, q);
}
System.exit(0);
}
else{
setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);
}
}
});
}
回答by Scuba Steve
Ok trying again.
好的，再试一次。
You cannot create a new WindowAdapterbecause WindowAdapter is abstract. Abstract classes cannot be instantiated. You would need to create a subclass of WindowAdapter and implement its abstract methods as public.
您不能创建新的 WindowAdapter，因为 WindowAdapter 是抽象的。抽象类不能被实例化。您需要创建 WindowAdapter 的子类并将其抽象方法实现为公共。
http://docs.oracle.com/javase/7/docs/api/java/awt/event/WindowAdapter.html
http://docs.oracle.com/javase/7/docs/api/java/awt/event/WindowAdapter.html
