从按钮打开一个新的 JFrame [英] Opening a new JFrame from a Button

问题描述

我想通过单击按钮 (btnAdd) 来打开一个新的 JFrame；我试图创建一个动作监听器，但我没有运气；代码运行但单击按钮时没有任何反应.有问题的方法是以下代码中的最后两个.非常感谢任何帮助！

I want to open a new JFrame by clicking a button (btnAdd); I have tried to create an actionlistener but I am having no luck; the code runs but nothing happens when the button is clicked. The methods in question are the last two in the following code. Any help is much appreciated!

package AdvancedWeatherApp;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.event.ListSelectionListener;

import weatherforecast.FetchWeatherForecast;

public class MainFrame extends JFrame implements ListSelectionListener {

private boolean initialized = false;
private Actions actions = new Actions();

private javax.swing.JScrollPane jspFavouritesList = new javax.swing.JScrollPane();
private javax.swing.DefaultListModel<String> listModel = new javax.swing.DefaultListModel<String>();
private javax.swing.JList<String> favouritesList = new javax.swing.JList<String>(
        listModel);

private javax.swing.JLabel lblAcknowledgement = new javax.swing.JLabel();
private javax.swing.JLabel lblTitle = new javax.swing.JLabel();

private javax.swing.JButton btnAdd = new javax.swing.JButton();
private javax.swing.JButton btnRemove = new javax.swing.JButton();

public void initialize() {
    initializeGui();
    initializeEvents();
    this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}

/**
 * 
 */
private void initializeGui() {
    if (initialized)
        return;
    initialized = true;
    this.setSize(500, 400);

    Dimension windowSize = this.getSize();
    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
    this.setLocation(screenSize.width / 2 - windowSize.width / 2,
            screenSize.height / 2 - windowSize.height / 2);
    Container pane = this.getContentPane();
    pane.setLayout(new BorderLayout());
    setLayout(new BorderLayout());
    setTitle("Favourite Weather Locations");

    JPanel jpSouth = new JPanel();
    jpSouth.setLayout(new FlowLayout());

    JPanel jpNorth = new JPanel();
    jpNorth.setLayout(new FlowLayout());

    JPanel jpCenter = new JPanel();
    jpCenter.setLayout(new BoxLayout(jpCenter, BoxLayout.PAGE_AXIS));

    JPanel jpEast = new JPanel();
    JPanel jpWest = new JPanel();

    getContentPane().setBackground(Color.WHITE);
    jpEast.setBackground(Color.WHITE);
    jpWest.setBackground(Color.WHITE);
    jpCenter.setBackground(Color.WHITE);

    getContentPane().add(jspFavouritesList);
    jpCenter.add(jspFavouritesList);
    jspFavouritesList.setViewportView(favouritesList);
    favouritesList
            .setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
    favouritesList.addListSelectionListener(this);

    jpCenter.add(btnAdd);
    jpCenter.add(btnRemove);
    jpCenter.setAlignmentY(CENTER_ALIGNMENT);
    btnAdd.setText("Add Location");
    btnAdd.setAlignmentX(Component.CENTER_ALIGNMENT);
    btnAdd.setFont(new Font("Calibri", Font.PLAIN, 18));

    jpCenter.add(btnRemove);
    btnRemove.setText("Remove Location");
    btnRemove.setAlignmentX(Component.CENTER_ALIGNMENT);
    btnRemove.setFont(new Font("Calibri", Font.PLAIN, 18));

    getContentPane().add(jpEast, BorderLayout.EAST);
    getContentPane().add(jpWest, BorderLayout.WEST);

    getContentPane().add(jpSouth);
    jpSouth.add(lblAcknowledgement);
    add(lblAcknowledgement, BorderLayout.SOUTH);
    lblAcknowledgement.setText(FetchWeatherForecast.getAcknowledgement());
    lblAcknowledgement.setHorizontalAlignment(SwingConstants.CENTER);
    lblAcknowledgement.setFont(new Font("Tahoma", Font.ITALIC, 12));

    getContentPane().add(jpNorth);
    jpNorth.add(lblTitle);
    add(lblTitle, BorderLayout.NORTH);
    lblTitle.setText("Your Favourite Locations");
    lblTitle.setHorizontalAlignment(SwingConstants.CENTER);
    lblTitle.setFont(new Font("Calibri", Font.PLAIN, 32));
    lblTitle.setForeground(Color.DARK_GRAY);

    getContentPane().add(jpCenter);

}

private void initializeEvents() {
    // TODO: Add action listeners, etc
}

public class Actions implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();
        command = command == null ? "" : command;
        // TODO: add if...if else... for action commands

    }
}

public void dispose() {
    // TODO: Save settings
    // super.dispose();
    System.exit(0);
}

public void setVisible(boolean b) {
    initialize();
    super.setVisible(b);
}

public static void main(String[] args) {

    new MainFrame().setVisible(true);
}

public void actionPerformed(ActionEvent evt){

    if (evt.getSource() == btnAdd) {
        showNewFrame();
        //OPEN THE SEARCH WINDOW    

        }

    }

private void showNewFrame() {
    JFrame frame = new JFrame("Search Window" );
    frame.setSize( 500,120 );
    frame.setLocationRelativeTo( null );
    frame.setVisible( true );   

}
}

推荐答案

尽管您已经按照 ActionListener 接口，您的类不是那种类型，因为您还没有实现em> 界面.一旦你实现了这个接口并用 JButton btnAdd 注册它，

Although you have implemented the actionPerformed method as per the ActionListener interface, you class is not of that that type as you haven't implemented the interface. Once you implement that interface and register it with the JButton btnAdd,

btnAdd.addActionListener(this);

该方法将被调用.

更紧凑的替代方案可能是使用匿名接口:

A more compact alternative might be to use an anonymous interface:

btnAdd.addActionListener(new ActionListener() {
   @Override
   public void actionPerformed(ActionEvent e) {
      // handle button ActionEvent & display dialog...    
   }
});

<小时>

附注:

• 在应用程序中使用多个 JFrame 会产生大量开销来管理可能需要存在于帧之间的更新.首选的方法是如果需要另一个窗口，请使用模态 JDialog.此处对此进行了更多讨论.

• Using more than one JFrame in an application creates a lot of overhead for managing updates that may need to exist between frames. The preferred approach is to use a modal JDialog if another window is required. This is discussed more here.

这篇关于从按钮打开一个新的 JFrame的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！