JFrame和JPanel问题

Question

I am attempting to make a program for a local bagel shop that sells pastries, bagels, and coffee. I am having trouble implementing the panels that I have made into the JFrame

any help understanding how to make my JFrame look like this would be helpful http://kepler.covenant.edu/COS150/Bagel_files/image002.jpg

Once I have this working I hope to have the middle set of panels change depending on which product is selected. I am not entirely sure how to make the buttons and panels talk to one another.

Thanks for the Help!

here is my code for the JFrame so far.

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class BagelOrder extends JFrame
{   
JLabel topLabel;

sizePanel sp = new sizePanel();
typePanel tp = new typePanel();
productsPanel pp = new productsPanel();
buttonPanel bp = new buttonPanel();
extrasPanel ep = new extrasPanel();

public BagelOrder()
{
    setTitle("Order Entry Screen");
    setSize(800, 800);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    topLabel = new JLabel("Order Entry Screen");
    add(pp, BorderLayout.WEST);
    add(topLabel, BorderLayout.NORTH);
    add(bp, BorderLayout.SOUTH);
    add(middleCoffeePanelSetBuild(), BorderLayout.CENTER);
    add(east, BorderLayout.EAST);
    setVisible(true);

}

private JPanel middleCoffeePanelSetBuild()
{
    JPanel middlePanel = new JPanel(new GridLayout(3,1));
    add(sp);
    add(tp);
    add(ep);

    }

public static void main(String args[])
{
    BagelOrder bo = new BagelOrder();
}



} 

I have no errors but I cannot see anything other than the label at the top of the page.

here is my code for the other classes

ButtonPanel

import java.awt.GridLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JPanel;


public class buttonPanel extends JPanel
{
JButton enterItemButton;
JPanel buttonPanel;
ButtonGroup bg;
JButton totalButton;
JButton newOrderButton;


public buttonPanel()
{
    buttonPanel = new JPanel(new GridLayout(1,3));
    bg = new ButtonGroup();
    enterItemButton = new JButton("Enter Item");
    totalButton = new JButton("Total");
    newOrderButton = new JButton("New Order");

    buttonPanel.setSize(150, 780);
    buttonPanel.add(enterItemButton);
    bg.add(enterItemButton);
    buttonPanel.add(totalButton);
    bg.add(totalButton);
    buttonPanel.add(newOrderButton);
    bg.add(newOrderButton);
    setVisible(true);   

}
}

ProductPanel

import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.border.Border;


public class productsPanel extends JPanel
{
public productsPanel()
{
    JPanel productPanel = new JPanel(new GridLayout(3,1));
    ButtonGroup bg = new ButtonGroup();
    JRadioButton coffeeButton = new JRadioButton("Coffee");
    JRadioButton bagelButton = new JRadioButton("Bagel");
    JRadioButton pastryButton = new JRadioButton("Pastry");

    productPanel.setSize(150, 780);
    productPanel.add(coffeeButton);
    bg.add(coffeeButton);
    productPanel.add(bagelButton);
    bg.add(bagelButton);
    productPanel.add(pastryButton);
    bg.add(pastryButton);

    Border etched = BorderFactory.createEtchedBorder();
    Border titled = BorderFactory.createTitledBorder(etched, "Products");
    productPanel.setBorder(titled);
    setVisible(true);   
}
}

Size Panel

import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.border.Border;


public class sizePanel extends JPanel{

public sizePanel()
{
    JPanel sp = new JPanel(new GridLayout(3,1));
    ButtonGroup bg = new ButtonGroup();
    JRadioButton smallButton = new JRadioButton("Small");
    JRadioButton mediumButton = new JRadioButton("Medium");
    JRadioButton largeButton = new JRadioButton("Large");

    sp.setSize(200, 200);
    sp.add(smallButton);
    bg.add(smallButton);
    sp.add(mediumButton);
    bg.add(mediumButton);
    sp.add(largeButton);
    bg.add(largeButton);


    Border etched = BorderFactory.createEtchedBorder();
    Border titled = BorderFactory.createTitledBorder(etched, "Size");   
    sp.setBorder(titled);
    setVisible(true);   
}
}

TypePanel

import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.border.Border;


public class typePanel extends JPanel
{
public typePanel()
{
    JPanel typePanel = new JPanel(new GridLayout(3,1));
    ButtonGroup bg = new ButtonGroup();
    JRadioButton regularButton = new JRadioButton("Regular");
    JRadioButton decafButton = new JRadioButton("Decaf");
    JRadioButton frenchRoastButton = new JRadioButton("French Roast");

    typePanel.setSize(200, 200);
    typePanel.add(regularButton);
    bg.add(regularButton);
    typePanel.add(decafButton);
    bg.add(decafButton);
    typePanel.add(frenchRoastButton);
    bg.add(frenchRoastButton);


    Border etched = BorderFactory.createEtchedBorder();
    Border titled = BorderFactory.createTitledBorder(etched, "Type");   
    typePanel.setBorder(titled);
    setVisible(true);   
}
}

ExtrasPanel

 import java.awt.GridLayout;
 import javax.swing.BorderFactory;
 import javax.swing.JCheckBox;
 import javax.swing.JPanel;
 import javax.swing.border.Border;


public class extrasPanel extends JPanel
{
public extrasPanel()
{
    JPanel extrasPanel = new JPanel(new GridLayout(2,1));

    JCheckBox creamCheckBox = new JCheckBox("Cream");
    JCheckBox sugarCheckBox = new JCheckBox("Sugar");   

    extrasPanel.setSize(200, 200);
    extrasPanel.add(creamCheckBox);
    extrasPanel.add(sugarCheckBox);

    Border etched = BorderFactory.createEtchedBorder();
    Border titled = BorderFactory.createTitledBorder(etched, "Extras");
    extrasPanel.setBorder(titled);
    setVisible(true);
}
}

Answer 1

Some good practices to get into when writing Swing GUI's:

1) Your Panel classes are built wrong. You need to re-write buttonPanel, and all of your others, so that they read like this:

public buttonPanel() {
    super(new GridLayout(1,3));
    bg = new ButtonGroup();
    enterItemButton = new JButton("Enter Item");
    totalButton = new JButton("Total");
    newOrderButton = new JButton("New Order");

    this.setSize(150, 780);
    this.add(enterItemButton);
    bg.add(enterItemButton);
    this.add(totalButton);
    bg.add(totalButton);
    this.add(newOrderButton);
    bg.add(newOrderButton);
    this.setVisible(true);

    }
}

The way yours is currently written, you have a ButtonPanel class (always capitalise classes) which posseses a JPanel with the buttons on it, but it never displays this JPanel that it owns. You need ButtonPanel to BE a JPanel, not just own one. Thats the major issue. Minor points you could improve on:

2) The JFrame has a JPanel called the contentPane. As said by jzd, when using JFrame.add you are really calling JFrame.getContentPane.add(Component c). This is a convenience method, but it hides what you are really doing. Especially when you're just learning, shortcuts are bad.

I personally go a step further, starting my JFrames off with

JPanel content = new JPanel(new BorderLayout());
content.add(...);
....
this.setContentPane(content);

3) It is good practice when extending a class (like JFrame) to begin with a call to super(). Again, you can leave it out as shorthand, but its good to be pedantic when beginning. This calls the superclass's constructor (with whatever arguments you need), which is basically saying "Lets create the basic JFrame, and then apply my extensions to it".

4) Its also good practice to capitalise your classes, and begin all functions with lowercase verbs. ie ButtonPanel or build()

5) It seems like you're only just starting out with GUI, but might I recommend the external library "MigLayout" (google it). Its amazing in the extra power and ease that it gives you over struggling against all of Java's inbuilt, horrible, layout types.

Answer 2

它们使用ActionListener接口， ActionPerformed(ActionEvent e)方法相互交谈，并且为了触发这些方法，您需要<the component to be listened to>.addActionListener(theListener);