java - JScrollPane 困惑

Question

因此，我尝试将 JScrollPane 添加到 JTextArea 中，以便可以向下滚动，但无论我做什么，该 Pane 都不会显示。我是否违反了某些 Swing 规则，或者只是失败了？另外，这是一个学校项目，所以我真的需要尽快得到明确的答案。谢谢! 下面是实现 JScrollPane 的类的代码:

package BLANK.historicalcontext;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Insets;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.WindowConstants;
import javax.swing.border.Border;

import BLANK.historicalcontext.gui.ConsoleJTextArea;
import BLANK.historicalcontext.keys.ConsoleKeyListener;
import BLANK.historicalcontext.story.Backstory;
import BLANK.historicalcontext.story.Story;

public class Window extends JFrame {
    public static ConsoleJTextArea console = new ConsoleJTextArea();
    public static JTextField inputField = new JTextField();

    public static Story currentStory;

    public static Font font = new Font("Avenir-Light", Font.PLAIN, 12);

    private void addComponentsToPane() {
        setLayout(null);

        Border border = BorderFactory.createLineBorder(Color.BLACK);

        inputField.addKeyListener(new ConsoleKeyListener());

        console.setEditable(false);

        console.setBackground(new Color(230, 230, 250));
        console.setBorder(BorderFactory.createCompoundBorder(border, BorderFactory.createEmptyBorder(5, 5, 5, 5)));
        console.setFont(font);

        inputField.setFont(font);

        Insets insets = getContentPane().getInsets();

        JScrollPane consoleScrollPane = new JScrollPane(console);
        consoleScrollPane.setPreferredSize(new Dimension(20 + insets.left, 800 - 20 + insets.top));

        getContentPane().add(inputField);
        getContentPane().add(consoleScrollPane);

        console.setBounds(10 + insets.left, 10 + insets.top, 800 - 20, 600 - 65);
        inputField.setBounds(7 + insets.left, (600 - 70) + 20 + insets.top, 800 - 14, 20);
    }

    private static void createAndShowGUI() {
        Window frame = new Window("Historical Context Project");
        frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);

        frame.addComponentsToPane();

        Insets insets = frame.getInsets();
        frame.setSize(800 + insets.left + insets.right, 600 + insets.top + insets.bottom);
        frame.setVisible(true);

        inputField.requestFocusInWindow();
    }

    public Window(String name) {
        super(name);
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
        } catch (UnsupportedLookAndFeelException ex) {
            console.printToConsole("UnsupportedLookAndFeelException caught: \n" + ex.getStackTrace().toString() + "\n");
        } catch (IllegalAccessException ex) {
            console.printToConsole("IllegalAccessException caught: \n" + ex.getStackTrace().toString() + "\n");
        } catch (InstantiationException ex) {
            console.printToConsole("InstantiationException caught: \n" + ex.getStackTrace().toString() + "\n");
        } catch (ClassNotFoundException ex) {
            console.printToConsole("ClassNotFoundException caught: \n" + ex.getStackTrace().toString() + "\n");
        }

        UIManager.put("swing.boldMetal", Boolean.FALSE);

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });

        console.append("Hello! This is a text-based game about the creation of the creation of Java.");
        console.printToConsole("Your name is Patrick Naughton.");
        console.printToConsole("Here is a bit of backstory:");

        currentStory = new Backstory();

        if(currentStory != null) {
            currentStory.executeStory();
        }
    }

    public static void failGame() {
        console.printToConsole("You failed the game. This application will close once you click the \"Enter\"/\"Return\" key.");
    }

}

我想您还想查看控制台所基于的类:

package nate.historicalcontext.gui;

import javax.swing.JTextArea;

@SuppressWarnings("serial")
public class ConsoleJTextArea extends JTextArea {

    public void printToConsole(String message) {
        this.append("\n"+ message);
    }

}

另外，请不要向我推荐另一个问题，因为没有两个问题是完全相似的，而且我的情况可能与该问题的作者不同。

Answer 1

1. 过度使用静态。 static 不是跨对象通信的手段。提供允许您访问其他对象所需的对象属性的方法。尝试保护您的数据/字段
2. null 布局。您无法控制渲染过程的许多方面，这些方面可能会更改各个组件的需求并影响它们与其他组件的关系。
3. 在之前将console 分配给JScrollPane 后将其添加到contentPane。组件只能驻留在单个容器中，当您将其添加到另一个容器时，它会先从当前容器中删除

仔细看看How to use scrollpanes了解更多详情

JScrollPane consoleScrollPane = new JScrollPane(console);
//...
// Add the scroll pane...
getContentPane().add(consoleScrollPane);
// Add the console, which WAS on the scrollpane to the content pane
getContentPane().add(console);

您使用 null 布局对您没有帮助...

  private void addComponentsToPane() {
    JPanel panel = new JPanel();
    panel.setBorder(new EmptyBorder(10, 10, 10, 10));
    setContentPane(panel);
    setLayout(new BorderLayout());

    Border border = BorderFactory.createLineBorder(Color.BLACK);

//  inputField.addKeyListener(new ConsoleKeyListener());

    console.setEditable(false);

    JScrollPane consoleScrollPane = new JScrollPane(console);

    console.setBackground(new Color(230, 230, 250));
    console.setBorder(BorderFactory.createCompoundBorder(border, BorderFactory.createEmptyBorder(5, 5, 5, 5)));
    console.setFont(font);

    inputField.setFont(font);

    getContentPane().add(inputField, BorderLayout.SOUTH);
    getContentPane().add(consoleScrollPane);
//  getContentPane().add(console);

    Insets insets1 = getContentPane().getInsets();
//  console.setBounds(10 + insets1.left, 10 + insets1.top, 800 - 20, 600 - 65);
//  inputField.setBounds(7 + insets1.left, (600 - 70) + 20 + insets1.top, 800 - 14, 20);
  }