使用JButton使用addActionListener处理JFrame

时间:2013-06-22 16:33:33

标签: java swing class jframe dispose

过去3天我一直试图解决这个问题:/

我有一个类Login(),它创建一个JFrame对象

另一个名为LoginTab()的类,它有一个带有JFrame-object作为参数的构造函数。

我想在LoginTab()类中使用Button处理JFrame。但addActionListener不接受JFrame对象,我不知道原因:(

LoginTab的代码():

package tabs;

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Locale;
import java.util.ResourceBundle;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;

import abstractClasses.JTextFieldImmo;
import abstractClasses.ValidateInput;

import programs.MySQL;
import windows.ButtonPanel;
import windows.UserDetails;

public class LoginTab extends ValidateInput {

/**
 * 
 */
private static final long serialVersionUID = 1L;

static Locale locale = new Locale("de");
static ResourceBundle r = ResourceBundle.getBundle("Strings", locale);

// static Connection con = null;
static Statement stnt = null;
static ResultSet rs = null;

public LoginTab(JFrame window) {
    panelMethod(window);
}

// LOGIN ITEMS
JLabel usernameLbl = new JLabel(r.getString("username"));
JLabel passwordLbl = new JLabel(r.getString("password"));
JTextFieldImmo usernameFld = new JTextFieldImmo(10);
JPasswordField passwordFld = new JPasswordField(10);
JButton loginBtn = new JButton(r.getString("login"));
JButton registerUserBtn = new JButton("Neuer Benutzer"); // TODO String
                                                            // einfügen

public void panelMethod(JFrame window) {

    this.setLayout(new GridBagLayout());

    GridBagConstraints c = new GridBagConstraints();

    // Insets
    c.insets = new Insets(4, 5, 0, 0);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 0;
    c.gridy = 0;
    this.add(usernameLbl, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 1;
    c.gridy = 0;
    this.add(usernameFld, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 0;
    c.gridy = 1;
    this.add(passwordLbl, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 1;
    c.gridy = 1;
    this.add(passwordFld, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 1;
    c.gridy = 2;
    this.add(loginBtn, c);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridx = 0;
    c.gridy = 2;
    this.add(registerUserBtn, c);

    // Actions Listener


    loginBtn.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            try {
                MySQL.connect();
                String username = usernameFld.getText().trim();
                String password = String.valueOf(passwordFld.getPassword())
                        .trim();

                String sql = "SELECT username,password from per_user where username = '"
                        + username + "'and password = '" + password + "'";
                stnt = MySQL.getCon().createStatement();
                rs = stnt.executeQuery(sql);

                int count = 0;

                while (rs.next()) {
                    count = count + 1;
                }

                if (count == 1) {
                    JOptionPane.showMessageDialog(null, "User Found, Access Granded!"); //TODO String
                    //window.setVisible(false);
                    //window.dispose();
                    new ButtonPanel();
                } else if (count > 1) {
                    JOptionPane.showMessageDialog(null,
                            "Duplicate User, Access Denied!"); // TODO String einfügen
                } else {
                    JOptionPane.showMessageDialog(null, "User not Found"); // TODO String einfügen
                }

            } catch (Exception e1) {
                // JOptionPane.showMessageDialog(null,
                // "Es konnte keine Verbindung zum MySQL Server hergestellt werden.");
                e1.printStackTrace();
            }

        }
    });

    registerUserBtn.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            new UserDetails();
        }
    });

    passwordFld.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            loginBtn.doClick();

        }
    });
}
}        

3 个答案:

答案 0 :(得分:2)

要在另一个对象上调用方法,您需要对该另一个对象的引用。我看到你的代码遇到的一个问题是无处(我无论如何都能看到)是否有对你当前可视化的Login对象的引用。要解决此问题,您需要获取此引用,可能通过构造函数参数或setter方法,然后关闭JFrame。

顺便说一下,不得不以这种方式关闭一个JFrame中间程序。您确定不应该使用模态对话框(如JDialog)来代替JFrame吗?

此外,您的代码显示了许多GUI组件,但它们在哪里添加到顶级窗口并显示?


修改
另请注意,您可以通过SwingUtilities方法获取封闭的顶级窗口:

SwingUtilities.getWindowAncestor(...);

答案 1 :(得分:2)

Closing an Application查看ExitAction。 ExitAction类将找到活动窗口,然后向该窗口发送关闭请求。所以这个类可以用来关闭任何窗口。

答案 2 :(得分:2)

您需要将window引用为final才能在匿名类ActionListener内访问它:

public void panelMethod(final JFrame window) {
    // obmitted code
}

然后:

loginBtn.addActionListener(new ActionListener() {
    // obmitted coce

    if (count == 1) {
    JOptionPane.showMessageDialog(null, "User Found, Access Granded!"); //TODO String
    window.setVisible(false);
    window.dispose();
    new ButtonPanel();
    }

    // ...
}

我建议您阅读Core Java Volumn I,以了解开发Java应用程序以及使用Swing组件的好方法。