元素定位和大小调整方面的问题 [英] Issues in locating elements and re sizing

问题描述

请看下面的代码

WizardPanel

package wizardGUI;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class WizardPanel extends JDialog
{
    private JPanel cardPanel, buttonPanel;
    private JButton next,previous;
    private CardLayout c1;

    private FileSelector fileSelector;
    private DelemeterSelector delemeterSelector;

    private int count = 1;

    public WizardPanel()
    {
        //Intializing instance variables
        fileSelector = FileSelector.getInstance();
        delemeterSelector = DelemeterSelector.getInstance();

        cardPanel = new JPanel();
        c1 = new CardLayout();
        cardPanel.setLayout(c1);

        cardPanel.add(fileSelector,"1");
        cardPanel.add(delemeterSelector,"2");

        c1.show(cardPanel, "1");;


        buttonPanel = new JPanel();
        buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));

        next = new JButton("Next");
        next.addActionListener(new NextButtonAction());
        previous = new JButton("Previous");

        buttonPanel.add(next);
        buttonPanel.add(previous);

        //Creating the GUI
        this.setLayout(new BorderLayout());
        this.add(cardPanel,"Center");
        this.add(buttonPanel,"South");

        this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        this.setResizable(true);
        this.pack();
        this.setVisible(true);

    }

    private class NextButtonAction implements ActionListener
    {
        public void actionPerformed(ActionEvent ae)
        {

                c1.show(cardPanel, "2");

        }
    }
}

FileSelector

package wizardGUI;

/*This is the first panel is wazard GUI. Using this window user can select the correct file
  which contains the data required to create the table
 */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class FileSelector extends JPanel
{
    private JLabel fileName, description;
    private JTextField fileTxt;
    private JButton browse;

    private GridBagLayout gbl;
    private GridBagConstraints gbc;

    private static FileSelector instance = null;

    private FileSelector()
    {
        //Intializing instance variables
        fileName = new JLabel("File Name: ");
        description = new JLabel("Specify the source of the data");

        fileTxt = new JTextField(10);

        browse = new JButton("Browse");

        gbl = new GridBagLayout();
        gbc = new GridBagConstraints();

        //Creating GUI
        this.setLayout(gbl);

        gbc.gridx = 1;
        gbc.gridy = 1;
        gbc.weightx = 0.0;
        gbc.weighty = 0.0;
        gbc.fill = GridBagConstraints.BOTH;
        this.add(description,gbc);

        gbc.gridx = 1;
        gbc.gridy = 2;
        gbc.weightx = 1.0;
        gbc.fill = GridBagConstraints.BOTH;
        gbc.insets = new Insets(0,10,0,0);
        this.add(locationPanel(),gbc);

        this.setBorder(BorderFactory.createEmptyBorder());
    }

    private JPanel locationPanel()
    {
        JPanel panel = new JPanel();
        panel.setLayout(new FlowLayout());

        panel.add(fileName);
        panel.add(fileTxt);
        panel.add(browse);

        return panel;
    }

    public static FileSelector getInstance()
    {
        if(instance==null)
        {
            instance = new FileSelector();
        }

        return instance;
    }
}

DelemeterSelector

/*This is the second windows in wizard
This class is designed to let the user to select the delemeter to break information */

package wizardGUI;

import java.awt.event.*;
import java.awt.*;
import javax.swing.*;

public class DelemeterSelector extends JPanel
{
    private JLabel description;
    private JRadioButton tabBtn, semicolanBtn, commaBtn, spaceBtn;
    private JTextArea txtArea;
    private JScrollPane scroll;
    private ButtonGroup btnGroup;

    private GridBagLayout gbl;
    private GridBagConstraints gbc;

    private static DelemeterSelector instance = null;

    private DelemeterSelector()
    {
        //Initializing instance variables
        description = new JLabel("What delemeter separates your fields? Select the appropreiate delemeter");

        tabBtn = new JRadioButton("Tab");
        semicolanBtn = new JRadioButton("Semicolan");
        commaBtn = new JRadioButton("Comma");
        spaceBtn = new JRadioButton("Space");

        btnGroup = new ButtonGroup();
        btnGroup.add(tabBtn);
        btnGroup.add(semicolanBtn);
        btnGroup.add(commaBtn);
        btnGroup.add(spaceBtn);

        txtArea = new JTextArea(20,70);

        scroll = new JScrollPane(txtArea);

        gbl = new GridBagLayout();
        gbc = new GridBagConstraints();

        this.setLayout(gbl);

        //Creating the GUI
        gbc.gridx = 1;
        gbc.gridy = 1;
        gbc.fill = GridBagConstraints.BOTH;
        gbc.insets = new Insets(20,0,0,0);
        this.add(description,gbc);

        gbc.gridx = 1;
        gbc.gridy = 2;
        gbc.fill = GridBagConstraints.BOTH;
        gbc.insets = new Insets(20,0,0,0);
        this.add(radioPanel(),gbc);

        gbc.gridx = 1;
        gbc.gridy = 3;
        gbc.insets = new Insets(10,0,0,0);
        gbc.fill = GridBagConstraints.BOTH;
        this.add(scroll,gbc);
    }

    private JPanel radioPanel()
    {
        JPanel panel = new JPanel();
        panel.setLayout(new FlowLayout());

        panel.add(tabBtn);
        panel.add(semicolanBtn);
        panel.add(commaBtn);
        panel.add(spaceBtn);

        panel.setBorder(BorderFactory.createTitledBorder("Choose the Delimeter that seperates your fields"));

        return panel;
    }

    public static DelemeterSelector getInstance()
    {
        if(instance == null)
        {
            instance = new DelemeterSelector();
        }

        return instance;
    }
}

运行代码时，"FileSelector"看起来非常丑陋.我希望所有内容都显示在窗格的顶部，但是，所有内容都显示在中间！我什至尝试使用GridBagLayout选项使其可调整大小，但也失败了.它的外观在所附的图片中

When I run the code, the "FileSelector" looks really ugly. I want everything to be appear at the top of the pane, but instead, everything appears in middle!! I have even tried GridBagLayout options to make it resizable, it also failed. The look of it is in the attached image

如何使它看起来美观且可扩展?请帮助

How can I make it look nice and scalable? Please help

推荐答案

只是一个简单的示例，它显示了相同的行为和修复，而无需所有外部代码(

Just a quick example which shows the same behavior and a fix, without the need for all that external code (an SSCCE)

import javax.swing.*;
import java.awt.*;

public class CardLayoutDemo {

  public static void main( String[] args ) {
    EventQueue.invokeLater( new Runnable() {
      @Override
      public void run() {
        JFrame frame = new JFrame( "TestFrame" );

        CardLayout cardLayout = new CardLayout();
        JPanel contentPane = new JPanel( cardLayout );

        JPanel firstPanel = new JPanel(  );
        firstPanel.setLayout( new BorderLayout(  ) );
        firstPanel.add( new JLabel( "Contents" ) );

        //wrap the smallest panel instead of directly adding it
        contentPane.add( firstPanel, "first" );
//        JPanel wrappedPanel = new JPanel( new BorderLayout(  ) );
//        wrappedPanel.add( firstPanel, BorderLayout.NORTH );
//        contentPane.add( wrappedPanel, "first" );

        JPanel secondPanel = new JPanel( new BorderLayout(  ) );
        secondPanel.add( new JComponent() {
          @Override
          public Dimension getPreferredSize() {
            return new Dimension( 500, 500 );
          }
        }, BorderLayout.CENTER );
        contentPane.add( secondPanel, "second" );

        cardLayout.show( contentPane, "first" );

        frame.setContentPane( contentPane );
        frame.pack();
        frame.setDefaultCloseOperation( WindowConstants.DISPOSE_ON_CLOSE );
        frame.setVisible( true );
      }
    } );
  }
}

在不做任何更改的情况下运行代码时，它将显示一个面板，其中内容居中(firstPanel).无需对firstPanel进行任何更改，只需将其包装即可将其保留在顶部.只需将contentPane.add( firstPanel, "first" )替换为下面的3行(在注释中).

When you run the code without making changes, it will show you a panel where the contents is centered (the firstPanel). Without making any changes to the firstPanel, but simply by wrapping it you can keep it at the top. Just replace the contentPane.add( firstPanel, "first" ) by the 3 lines (in comment) underneath.

很多时候嵌套布局可以更轻松地获得所需的结果，而imo这是一个其中

There are a lot of times where nesting layouts makes it easier to get the desired result, and imo this is one of them.

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