如何显示和隐藏现有的JFrame

Question

I am doing some basic tests to understand how Java Swing works.

I have a test application which consist of three fully independent windows (JFrames):

1. Main Menu
2. Asset Window 1
3. Asset Window 2

The Main Menu has a JButton which will show/hide Asset Window 1 ( a1 ).

This is the main class to launch all windows:

package test1;

import test1.AssetList.AssetList;
import test1.MainMenu.MainMenu;
import javax.swing.*;

public class Test1 {

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                MainMenu m = new MainMenu();
                AssetList a1 = new AssetList();
                AssetList a2 = new AssetList();
            }
        });
    }
}

This is the class with the Asset Window JFrame:

package test1.AssetList;

import javax.swing.*;

public class AssetList extends JFrame {

    public AssetList() {

        JLabel label = new JLabel("Asset list");
        this.getContentPane().add(label);

        this.pack();
        this.setVisible(false);

    }

}

This is the class for the MainMenu JFrame:

package test1.MainMenu;

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

public class MainMenu extends JFrame {

    JLabel label = new JLabel("Main Menu");
    JButton button = new JButton("Asset");  

    public MainMenu() {
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        this.getContentPane().add(label);
        this.getContentPane().add(button);

        button.addActionListener(new ButtonAssetListener());

        this.pack();
        this.setVisible(true);

    }

}

This is the class for the Asset Window Button JButton listener:

package test1.MainMenu;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class ButtonAssetListener implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent evt) {

        System.out.println("CLICK!");
        /* PSEUDOCODE
        if(a1 from Test1.isVisible()==true) {
           a1 from Test1.setVisible(false);
        } else {
            a1 from Test1.setVisible(true);
        }
        */
    }

}

How can I retrieve the a1 instance from ButtonAssetListener in order to toggle its visibility? Is there a better alternative to structure this kind of multiple windows application in Java Swing?

Answer 1

You can just pass the instance you want to hide to the button listener.

public class Test1 {

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                AssetList a1 = new AssetList();
                AssetList a2 = new AssetList();
                MainMenu m = new MainMenu(a1);
            }
        });
    }
}

Make your main menu take in a component which it will show and hide.

public class MainMenu extends JFrame {

    JLabel label = new JLabel("Main Menu");
    JButton button = new JButton("Asset");  

    public MainMenu(JComponent assetList) {
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        this.getContentPane().add(label);
        this.getContentPane().add(button);

        button.addActionListener(new ButtonAssetListener(assetList));

        this.pack();
        this.setVisible(true);

    }

}

Then modify your your button asset listener to take in a component which it will then show or hide.

public class ButtonAssetListener implements ActionListener{

    private JComponent component;

    public ButtonAssetListener(JComponent component) {
        this.component = component;
    }

    @Override
    public void actionPerformed(ActionEvent evt) {
        if(component.isVisible()) {
           component.setVisible(false);
        } else {
            component.setVisible(true);
        }
    }
}