java - GridBagLayout 不使用 anchor

Question

这里我试图将组件(按钮)锚定到面板的一侧，但我的 GridBagConstraints 显然遗漏了一些东西。如果可能的话，我希望它们有填充物；知道我会怎么做这样的事情 ？我可以只使用 Insets 作为填充吗？为任何帮助干杯。

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.io.IOException;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;

@SuppressWarnings("serial")
public class PlayGamePanel extends JComponent{

    @SuppressWarnings("unused")
    JComponent GamePanel2() throws IOException {

        JComponent GamePanel = new JLabel();

        //Setting up the gridbaglayout
        GamePanel.setLayout(new GridBagLayout());
        GridBagConstraints gbLayout = new GridBagConstraints();

        /*//Creating a button to test out switching panels
         * 
        JButton testButton = new JButton ("test");
        GamePanel.add(testButton);*/

        //Creating buttons for answering the quiz

        gbLayout.gridx = 0;
        gbLayout.gridy = 0;
        gbLayout.weightx = 1.0;
        gbLayout.anchor = GridBagConstraints.NORTHWEST;
        gbLayout.insets = new Insets(20, 20, 20, 20);

        JButton AnswerOneButton = new JButton("Answer One");
        GamePanel.add(AnswerOneButton);
        GamePanel.add(AnswerOneButton, gbLayout);

        gbLayout.gridx = 0;
        gbLayout.gridy = 0;
        gbLayout.weightx = 1.0;
        gbLayout.anchor = GridBagConstraints.NORTHEAST;
        gbLayout.insets = new Insets(20, 20, 20, 20);

        JButton AnswerTwoButton = new JButton("Answer Two");
        GamePanel.add(AnswerTwoButton);
        GamePanel.add(AnswerTwoButton, gbLayout);

        gbLayout.gridx = 0;
        gbLayout.gridy = 0;
        gbLayout.weightx = 1.0;
        gbLayout.anchor = GridBagConstraints.SOUTHEAST;
        gbLayout.insets = new Insets(20, 20, 20, 20);

        JButton AnswerThreeButton = new JButton("Answer Three");
        GamePanel.add(AnswerThreeButton);
        GamePanel.add(AnswerThreeButton, gbLayout);


        gbLayout.gridx = 0;
        gbLayout.gridy = 0;
        gbLayout.weightx = 1.0;
        gbLayout.anchor = GridBagConstraints.SOUTHWEST;
        gbLayout.insets = new Insets(20, 20, 20, 20);


        JButton AnswerFourButton = new JButton("Answer Four");
        GamePanel.add(AnswerFourButton);
        GamePanel.add(AnswerFourButton, gbLayout);

        return GamePanel;
    }
}

Answer 1

添加组件时，您需要将 GridBagConstraints 传递给容器...

例如...

GamePanel.add(AnswerOneButton, gbLayout);

您还需要提供每个组件的单元格位置，例如...

gbLayout.gridx = 0;
gbLayout.gridy = 0;
JButton AnswerOneButton = new JButton("Answer One");
GamePanel.add(AnswerOneButton, gbLayout);

将 AnswerOneButton 按钮放置在第一行的第一列中。

您可以使用 insets 属性为每个单元格提供填充，例如...

gbLayout.weightx = 1.0;
gbLayout.gridx = 0;
gbLayout.gridy = 0;
gbLayout.insets = new Insets(20, 20, 20, 20);
JButton AnswerOneButton = new JButton("Answer One");
GamePanel.add(AnswerOneButton, gbLayout);

现在，就我个人而言，我会使用 NORTHEAST、NORTHWEST、SOUTHEAST 和 SOUTHWEST 作为 anchor ，它只是对我来说更有意义......

gbLayout.weightx = 1.0;
gbLayout.gridx = 0;
gbLayout.gridy = 0;
gbLayout.insets = new Insets(20, 20, 20, 20);
gbLayout.anchor = GridBagConstraints.NORTHWEST;
JButton AnswerOneButton = new JButton("Answer One");
GamePanel.add(AnswerOneButton, gbLayout);

更新所有按钮的所有约束后，我得到类似......的内容

您可能想看看 How to Use GridBagLayout了解更多详情...

您可能还想阅读Code Conventions for the Java Programming Language ，这将使人们更容易阅读您的代码;)

使用JLabel作为主要容器也是一个相当有趣的选择，您可能会发现JPanel提供了更好的支持

已更新示例代码

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestLayout {

    public static void main(String[] args) {
        new TestLayout();
    }

    public TestLayout() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(GamePanel2());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    @SuppressWarnings("unused")
    JComponent GamePanel2() {

        JComponent GamePanel = new JPanel();
        GamePanel.setOpaque(false);

        //Setting up the gridbaglayout
        GamePanel.setLayout(new GridBagLayout());
        GridBagConstraints gbLayout = new GridBagConstraints();

        /*//Creating a button to test out switching panels
         * 
         JButton testButton = new JButton ("test");
         GamePanel.add(testButton);*/
        //Creating buttons for answering the quiz
        gbLayout.gridx = 0;
        gbLayout.gridy = 0;
        gbLayout.weightx = 1.0;
        gbLayout.anchor = GridBagConstraints.NORTHWEST;
        gbLayout.insets = new Insets(20, 20, 20, 20);
        JButton AnswerOneButton = new JButton("Answer One");
        GamePanel.add(AnswerOneButton, gbLayout);

        gbLayout.gridx = 1;
        gbLayout.anchor = GridBagConstraints.NORTHEAST;
        JButton AnswerTwoButton = new JButton("Answer Two");
        GamePanel.add(AnswerTwoButton, gbLayout);

        gbLayout.gridx = 0;
        gbLayout.gridy = 1;
        gbLayout.anchor = GridBagConstraints.SOUTHWEST;
        JButton AnswerThreeButton = new JButton("Answer Three");
        GamePanel.add(AnswerThreeButton, gbLayout);

        gbLayout.gridx = 1;
        gbLayout.gridy = 1;
        gbLayout.weightx = 1.0;
        gbLayout.anchor = GridBagConstraints.SOUTHEAST;
        JButton AnswerFourButton = new JButton("Answer Four");
        GamePanel.add(AnswerFourButton);
        GamePanel.add(AnswerFourButton, gbLayout);

        return GamePanel;
    }

}