使用dispose()方法关闭Java中的JFrame时遇到问题
问题描述:
因此,这是问题所在。我正在创建一个使用JFrame的程序。基本上它所做的是打开一个窗口,询问你打开哪个窗口。该程序由多个GUI类和多个Client类组成,负责为每个GUI在打开时创建一个新窗口。所以当MainClient类被加载时,它会创建一个窗口来保存MainGUI类。从那里从ComboBox中选择一个选项并单击“continue”应该启动另一个客户端类打开另一个JFrame。这一切都工作正常,除了我不能为我的生活找出为什么我不能使用.dispose()方法来删除旧窗口。我所能做的就是使用setVisible(false)方法将其清除,但它仍然在我新窗口的背景中挂起。每当我尝试直接在setVisible()方法之后使用dispose方法时,出现此错误“无法找到符号 - 方法dispose()” 如果有人知道为什么会发生这种情况,我希望对此有所帮助!下面是导致该错误我MainGUI类的代码(该错误是接近底部注释出来,并用星号包围):使用dispose()方法关闭Java中的JFrame时遇到问题
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class MainGUI extends JPanel
{
protected JLabel topLabel;
protected JButton continueButton;// To continue to the next form
private MainHandler handler = new MainHandler(this); // An instance of the inner event handler
protected final String[] OPTIONS = {"Search/Delete Employee Records","Insert New Employee",
"Insert New Manager","Retrieve Department Metadata"};
protected JComboBox optionsCombo; //Combo box to select options from
protected InsManGUI insGUI;
public MainGUI()
{
setLayout (new FlowLayout());
topLabel = new JLabel("Please select which action you wish to perform");
topLabel.setHorizontalAlignment(JLabel.CENTER);
continueButton = new JButton("Continue");
continueButton.setHorizontalAlignment(JLabel.CENTER);
optionsCombo = new JComboBox(OPTIONS);
add(topLabel);
add(optionsCombo);
add(continueButton);
continueButton.addActionListener(new MainHandler(this));
optionsCombo.addActionListener(new MainHandler(this));
}
}
// Inner eventhandler class to compute which form to open once the Continue button is clicked.
class MainHandler implements ActionListener
{
//Private varible to hold an instance of the MainGUI class
private MainGUI gui;
public MainHandler(MainGUI gui)
{
//Set the private GUI varible to a particular GUI
this.gui = gui;
EmployeesDB.connect();
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == gui.continueButton)
{
if(gui.optionsCombo.getSelectedItem() == "Insert New Manager")
{
gui.setVisible(false);
InsManClient man = new InsManClient();
//gui.dispose();*******************THIS LINE WON't //COMPILE*************************
}
if(gui.optionsCombo.getSelectedItem() == "Insert New Employee")
{
gui.setVisible(false);
InsEmpClient emp = new InsEmpClient();
}
if(gui.optionsCombo.getSelectedItem() == "Search/Delete Employee Records")
{
gui.setVisible(false);
SearchClient ser = new SearchClient();
}
if(gui.optionsCombo.getSelectedItem() == "Retrieve Department Metadata")
{
gui.setVisible(false);
MetaDataClient met = new MetaDataClient();
}
}
}
}
答
你MainGUI
类扩展JPanel
,不JFrame
。如果你想出售持有MainGUI
面板的实例的框架,你可以使用:
((JFrame) SwingUtilities.getWindowAncestor(gui)).dispose();
它也好像你正在使用一个以上的JFrame
,看The Use of Multiple JFrames: Good or Bad Practice?
'gui'是'的JPanel ',不是'JFrame','JPanel'没有'dispose()'方法。 ['JPanel'文档](https://docs.oracle.com/javase/7/docs/api/javax/swing/JPanel.html)。 –