使用GridBagLayout在一个面板中设置多个组件，但我不想填满整个面板

Question

我正在开展一个项目，我正在使用 java swing 构建 GUI。目前我在 JFrame 中有一个 Jpanel 应该包含一个标签（问题）和一组 buttons/textfield （答案），它可以根据被问到的问题而改变.我想让问题集中在顶部的某个地方，答案适当地集中在中间。目前我使用 GridBagLayout 设置 JLabel 和 JButtons 但仍然没有成功。

public class QuestionPanel extends MoviePanel{

    private String question;

    public QuestionPanel(String type, Application app, String question) throws Exception{
        super(type, app);
        this.question = question;
        JLabel lab = new JLabel(this.question);

        this.getGbc().anchor = GridBagConstraints.PAGE_START;
        this.getGbc().fill = GridBagConstraints.HORIZONTAL;
        this.getGbc().weighty = 0.5;
        this.getGbc().gridx = 2;
        this.getGbc().gridy = 0;

        lab.setFont(new Font("Helvetica", Font.BOLD, 40));
        lab.setForeground(new Color(189, 189, 189, 255));
        add(lab, this.getGbc());

        getAnswers(type);
    }

    private void getAnswers(String type){
        if(type.equals("AgeRestriction")){
            this.getGbc().gridx=0;
            this.getGbc().gridy=1;
            add(new YesButton(this.getApp()),this.getGbc());

            this.getGbc().gridx = 3;
            this.getGbc().gridy = 1;
            add(new NoButton(this.getApp()),this.getGbc());
        }
    }
}

GridBagLayout 设置在 super MoviePanel 和 this.getGbc() returns 合适的 GridBagConstraints。目前我的布局如下所示：

想法是让“是”和“否”按钮彼此靠近，并将未来的按钮动态定位在中心。

解决方案

我最终通过结合 angushjoshi and c0der 的答案解决了问题，因此在带有 GridBagLayout 的问题面板中添加了一个 answerPanel。我的代码现在看起来像这样：

public class QuestionPanel extends MoviePanel {

    private String question;
    private JPanel answerPanel = new JPanel();

    public QuestionPanel(String type, Application app, String question) throws Exception {
        super(type, app);
        this.question = question;
        JLabel lab = new JLabel(this.question);
        answerPanel.setOpaque(false);


        this.getGbc().anchor = GridBagConstraints.PAGE_START;
        this.getGbc().weighty = 1;
        this.getGbc().gridy = 0;
        this.getGbc().gridx = 2;
        this.getGbc().gridwidth = 3;

        lab.setFont(new Font("Helvetica", Font.BOLD, 40));
        lab.setForeground(new Color(189, 189, 189, 255));
        add(lab, this.getGbc());

        getAnswers(type);
    }

    public void getAnswers(String type) {
        if (type.equals("AgeRestriction")) {
            createYesNoButtons();
        }
        if (type.equals("Age")) {
            createAgeField();
        }
        if (type.equals("Genre")){
            createGenreButtons();
        }
        if (type.equals("Actor")){
            createActorField();
        }
    }


    private void createYesNoButtons() {
        this.getGbc().weighty = 0.5;
        this.getGbc().anchor = GridBagConstraints.CENTER;
       answerPanel.add(new YesButton(this.getApp()));
       answerPanel.add(new NoButton(this.getApp()));
       this.add(answerPanel,this.getGbc());
    }

    private void createAgeField() {
        this.getGbc().weighty = 0.5;
        this.getGbc().anchor = GridBagConstraints.CENTER;
        answerPanel.add(new AgeField(this.getApp()));
        this.add(answerPanel,this.getGbc());
    }

    private void createGenreButtons(){
    }

    private void createActorField(){
    }

}

现在面板看起来像这样：

感谢您的帮助！

Answer 1

很难为您的问题提供确切的解决方案，但我可以告诉您，您可能想尝试使用 GridBagConstraints.insets 和 GridBagConstraints.anchor。

insets 用于更改布局中对象周围的填充，即距 JPanel 边缘的最小距离。你可以这样使用它：

this.getGbc().insets = new Inset(top,right,bottom,left);

anchor 用于表示您希望对象在布局中的放置位置，例如： this.getGbc().anchor = GridBagConstraints.CENTER;

这里有一些有用的 GridBagConstraints.anchor 值：

FIRST_LINE_START ... PAGE_START ... FIRST_LINE_END

LINE_START ... 中心 ... LINE_END

最后_LINE_START ... PAGE_END ... 最后_LINE_END

Answer 2

我建议将布局分成更小、更易于布局的部分。在这种情况下使用 3 JPanels 并通过以下 MRE:

进行演示

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridBagLayout;
import java.awt.Image;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class QuestionAnswerPanel extends JPanel{

    private Image background;
    //use publicly available resources when posting questions or answers
    private final String imageLink = "https://www.whatsonnetwork.co.uk/uploads/800x600/98331337cb0f7f31c874e22a8f2b5f8b.jpg";

    QuestionAnswerPanel() {

        URL url;
        try {
            url = new URL(imageLink);
            background = ImageIO.read(url);
            setPreferredSize(new Dimension(background.getWidth(null), background.getHeight(null)));
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        //border layout  allows you to add components to 5 positions,
        //including north and center
        setLayout(new BorderLayout());

        //have a JPanel for the question
        JLabel lab = new JLabel("To Be Or Not To Be ?");
        lab.setFont(new Font("Helvetica", Font.BOLD, 40));
        lab.setForeground(new Color(189, 189, 189, 255));
        JPanel questionPanel = new JPanel();
        questionPanel.setOpaque(false);
        questionPanel.add(lab);
        add(questionPanel, BorderLayout.NORTH); //place it at the top

        //have a JPanel for the answer
        JPanel answerPanel = new JPanel();
        answerPanel.setOpaque(false);
        //use GridBagLayout to center components
        answerPanel.setLayout(new GridBagLayout());
        //add components as you need
        answerPanel.add(new JButton("Yes"));
        answerPanel.add(new JButton("No"));
        add(answerPanel, BorderLayout.CENTER);//place it at the center
    }


    @Override //Override to paint image at the background
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(background, 0, 0, null);
    }

    public static void main(String[] args) throws IOException {
        JFrame frame=new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new QuestionAnswerPanel());
        frame.pack();
        frame.setVisible(true);
    }
}

使用GridBagLayout在一个面板中设置多个组件，但我不想填满整个面板

Using GridBagLayout to set multiple components in one panel, but I dont want to fill up the whole panel

java

layout

swing

jpanel

gridbaglayout

解决方案