GridBagLayout Java

Question

嗨，我再次放入我的原始代码，只是为了让你看到我正在谈论的GridBagConstrainsts，我试图将每个图像贴在面板的南边，彼此紧贴在一起

package prototype;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

import javax.swing.WindowConstants;

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Image;
import javax.imageio.ImageIO;

import javax.swing.ImageIcon;
import javax.swing.JCheckBox;
//Declare the class which extends JFrame and
//implements ActionListener to enable bottons to respond whenever clicked or selected
public class Master extends JFrame implements ActionListener {

    //create the bottons visible by the user
    JButton check = new JButton("");
    JButton playList = new JButton("");
    JButton update = new JButton("");
    JButton quit = new JButton("");
    JCheckBox tick = new JCheckBox("Tick");

    JPanel top = new JPanel();

    public static void main(String[] args) {

        //declare object of the class
        Master jf = new Master();
    }

    public Master() {
        setLayout(new BorderLayout());
        setSize(1050, 400);
        setTitle("Master");

        // close application only by clicking the quit button
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        //show the frame in the middle of the screen when run
        setLocationRelativeTo(null);

        top.add(new JLabel("Select an option by clicking one of the buttons below"));
        add("North", top); // add the text above to the upper part of the frame (North)
        JPanel bottom = new JPanel();
        bottom.setLayout(new GridBagLayout());
        bottom.add(check);
        check.addActionListener(this);
        bottom.add(playList);
        playList.addActionListener(this);
        bottom.add(update);
        update.addActionListener(this);
        bottom.add(quit);
        quit.addActionListener(this);
        add("South", bottom);

        //make the frame non resizable but visible
        setResizable(true);
        setVisible(true);

        try{
       Image  img = ImageIO.read(getClass().getResource("gui/Exit.png"));
       Image resize = img.getScaledInstance(290, 180, 18);
       quit.setIcon(new ImageIcon(resize));
       img = (bottom, new JLabel("NAME"), 0,0,1,1, GridBagConstraints.SOUTH);


        }catch(Exception e){
        }
        try{
       Image  img = ImageIO.read(getClass().getResource("gui/Untitled.png"));
       Image resize = img.getScaledInstance(290, 180, 18);
       check.setIcon(new ImageIcon(resize));

        }catch(Exception e){
        }
        try{
       Image  img = ImageIO.read(getClass().getResource("gui/CPL.png"));
       Image resize = img.getScaledInstance(290, 180, 18);
       playList.setIcon(new ImageIcon(resize));

        }catch(Exception e){
        }
        try{
       Image  img = ImageIO.read(getClass().getResource("gui/UpdateLib.png"));
       Image resize = img.getScaledInstance(290, 180, 18);
       update.setIcon(new ImageIcon(resize));

        }catch(Exception e){
        }

    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == check) {
            new CheckLibrary();
        } else if (e.getSource() == update) {
            new UpdateLibrary();
        } else if (e.getSource() == quit) {
            System.exit(0);
        } else if (e.getSource() == playList)   {
            new CreatePlaylist();

    }
}
}

Answer 1

为此，您需要使用GridBagConstraints的anchor和weighty属性。

在下一个示例中，我将JTextField设置为南边：

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.JFrame;
import javax.swing.JTextField;

public class Example extends JFrame {

    public Example (){
        JTextField f = new JTextField(20);

        setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();
        c.anchor = GridBagConstraints.SOUTHEAST;
        c.weighty = 1;
        add(f,c);
    }

    public static void main(String...strings ){
        Example e = new Example();
        e.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        e.pack();
        e.setLocationRelativeTo(null);
        e.setVisible(true);
    }

}

如果您需要按组件填充所有水平空间，请添加下一步：

c.weightx = 1;
c.fill = GridBagConstraints.HORIZONTAL;

​

​

在我的示例中，对于Image，您可以使用JLabel而不是JTextField：

JLabel l = new JLabel(new ImageIcon(getClass().getResource(PATH_TO_IMAGE)));

Answer 2

您不能将图像直接添加到JPanel。相反，您可以将图像设置为JPanel或JLabel的图像图标，并将其添加到您正在尝试制作的任何内容中。