我无法从主类获取我的 JFrame 来显示另一个类的 JPanel。一切都编译无误。

JFrameTest.java:

package jframetest;

import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;


public class JFrameTest extends JFrame {

    public JFrameTest() {

        FlowLayout mainLayout = new FlowLayout();
        setSize(320, 480);
        setResizable(false);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(mainLayout);

        JPanel panelMain = new JPanel(mainLayout);

        JButton testButton = new JButton("Test12");
        panelMain.add(testButton);

        JPanelOne panel = new JPanelOne();
        panelMain.add(panel);
        panel.setVisible(true);
        add(panelMain);



    }

    public static void main(String[] arguments) {

        JFrameTest frame = new JFrameTest();
        frame.setVisible(true);


    }
}

JPanelOne.java:

package jframetest;

import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JPanel;


public class JPanelOne extends JPanel {

    public JPanelOne() {

        FlowLayout layoutPanel = new FlowLayout();
        JPanel panel = new JPanel(layoutPanel);
        JButton button = new JButton("test");
        panel.add(button);
        panel.setVisible(true);

    }

}

将不同的 JPanel 保留在它们自己的类中是一种好的做法吗？ (示例:希望 JFrame 包含几个相同大小的 JPanel，这将通过将 setVisible() 设置为 true/false 来切换)

编辑

感谢您的所有回答。著名的。现在回到我的问题:

既然我知道如何添加在其他类中创建的单个 GUI 元素，我想知道是否可以在其中一个类中使用布局管理器组织元素(可能在 JPanel 以外的其他容器中)，因此我可以添加它们作为一个组织在布局中的组(这就是为什么我问关于在其他类中创建整个 JPanel 的原因)。如图:

此示例的 JPanel(第二类)代码为:

package jframetest;

import java.awt.*;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSeparator;
import net.miginfocom.swing.MigLayout;


public class JPanelOne extends JPanel {

    private JPanel panelSettingsMain;
    private JLabel labelChooseLanguage, labelWordsCollection;
    private JButton buttonSelectLanguage, buttonSelectCollection,
            buttonStatistics, buttonPrintingOptions, buttonAddNewWordCollection,
            buttonInterfaceCustomization;
    private JSeparator separatorSettingsOne, separatorSettingsTwo,
            separatorSettingsThree, separatorSettingsFour,
            separatorSettingsFive;
    private Color greenRegular, separatorGreenLight, separatorGreenDark;

    public JPanelOne() {

        // creating settings main panel

        // setting up layout managers
        MigLayout layoutSettingsMain = new MigLayout(
                "insets 3 0 0 0");

        // setting up colors
        greenRegular = new Color(30, 165, 145);
        separatorGreenLight = new Color(190, 240, 220);
        separatorGreenDark = new Color(130, 205, 180);

        panelSettingsMain = new JPanel(layoutSettingsMain);
        panelSettingsMain.setBackground(Color.WHITE);

            // setting up choose language label
            labelChooseLanguage = new JLabel("Choose language:");
            panelSettingsMain.add(labelChooseLanguage,
                    "gapleft 10, gaptop 15, width 200");

            // setting up select language button
            buttonSelectLanguage = new JButton("language");
            buttonSelectLanguage.setForeground(greenRegular);
            buttonSelectLanguage.setFocusPainted(false);
            buttonSelectLanguage.setBorder(null);
            buttonSelectLanguage.setContentAreaFilled(false);
            buttonSelectLanguage.setCursor(new java.awt.Cursor(
                    java.awt.Cursor.HAND_CURSOR));
            panelSettingsMain.add(buttonSelectLanguage, "gapbottom 15px, wrap");

            // setting up light separator
            separatorSettingsOne = new JSeparator();
            separatorSettingsOne.setForeground(separatorGreenLight);
            panelSettingsMain.add(separatorSettingsOne,
                    "span 2, width 320, gapbottom 15, wrap");

            // setting up words collection label
            labelWordsCollection = new JLabel("Words collection:");
            panelSettingsMain.add(labelWordsCollection, "gapleft 10");

            // setting up selectcollection button
            buttonSelectCollection = new JButton("collection");
            buttonSelectCollection.setForeground(greenRegular);
            buttonSelectCollection.setFocusPainted(false);
            buttonSelectCollection.setBorder(null);
            buttonSelectCollection.setContentAreaFilled(false);
            buttonSelectCollection.setCursor(new java.awt.Cursor(
                    java.awt.Cursor.HAND_CURSOR));
            panelSettingsMain.add(buttonSelectCollection,
                    "gapbottom 15px, wrap");

            // setting up dark separator
            separatorSettingsTwo = new JSeparator();
            separatorSettingsTwo.setForeground(separatorGreenDark);
            panelSettingsMain.add(separatorSettingsTwo,
                    "span 2, width 320, gapbottom 15px, wrap");

            // setting up show statistics button
            buttonStatistics = new JButton("Show statistics");
            buttonStatistics.setForeground(greenRegular);
            buttonStatistics.setFocusPainted(false);
            buttonStatistics.setBorder(null);
            buttonStatistics.setContentAreaFilled(false);
            buttonStatistics.setCursor(new java.awt.Cursor(
                    java.awt.Cursor.HAND_CURSOR));
            panelSettingsMain.add(buttonStatistics,
                    "gapleft 10, gapbottom 15px, , wrap");

            // setting up dark separator
            separatorSettingsThree = new JSeparator();
            separatorSettingsThree.setForeground(separatorGreenDark);
            panelSettingsMain.add(separatorSettingsThree,
                    "span 2, width 320, gapbottom 15px, wrap");

            // setting up printing options button
            buttonPrintingOptions = new JButton("Printing options");
            buttonPrintingOptions.setForeground(greenRegular);
            buttonPrintingOptions.setFocusPainted(false);
            buttonPrintingOptions.setBorder(null);
            buttonPrintingOptions.setContentAreaFilled(false);
            buttonPrintingOptions.setCursor(new java.awt.Cursor(
                    java.awt.Cursor.HAND_CURSOR));
            panelSettingsMain.add(buttonPrintingOptions,
                    "gapleft 10, gapbottom 15px, wrap");

            // setting up dark separator
            separatorSettingsFour = new JSeparator();
            separatorSettingsFour.setForeground(separatorGreenDark);
            panelSettingsMain.add(separatorSettingsFour,
                    "span 2, width 320, gapbottom 15px, wrap");

            // setting up add new word collection button
            buttonAddNewWordCollection = new JButton("Add new word collection");
            buttonAddNewWordCollection.setForeground(greenRegular);
            buttonAddNewWordCollection.setFocusPainted(false);
            buttonAddNewWordCollection.setBorder(null);
            buttonAddNewWordCollection.setContentAreaFilled(false);
            buttonAddNewWordCollection.setCursor(new java.awt.Cursor(
                    java.awt.Cursor.HAND_CURSOR));
            panelSettingsMain.add(buttonAddNewWordCollection,
                    "gapleft 10, gapbottom 15px, , wrap");

            // setting up dark separator
            separatorSettingsFive = new JSeparator();
            separatorSettingsFive.setForeground(separatorGreenDark);
            panelSettingsMain.add(separatorSettingsFive,
                    "span 2, width 320, gapbottom 10px, wrap");

            // setting up interface customization button
            buttonInterfaceCustomization = new JButton(
                    "Interface customization");
            buttonInterfaceCustomization.setForeground(greenRegular);
            buttonInterfaceCustomization.setFocusPainted(false);
            buttonInterfaceCustomization.setBorder(null);
            buttonInterfaceCustomization.setContentAreaFilled(false);
            buttonInterfaceCustomization.setCursor(new java.awt.Cursor(
                    java.awt.Cursor.HAND_CURSOR));
            panelSettingsMain.add(buttonInterfaceCustomization,
                    "gapleft 10, gapbottom 15px, wrap");

    }

}

我正在考虑通过将 JPanel(如示例中的那些)设置为可见或不可见来浏览程序 GUI。

1. 这样做的好方法吗？
2. 我应该将我的 GUI 分成几个类，还是应该将所有内容都放在一个类中？我在问，因为现在代码中只有一半的 GUI，它大约有 400 行长(此时它除了“看”之外什么也做不了)。正如我之前所说 - 我是初学者，它是我迄今为止写的最长的应用程序之一(我确信它不会那么长!)。

编辑

也许我想多了，所以最终是否可以拥有大的 GUI 类并通过将它们设置为可见或不可见来控制不同 GUI 区域的可见性？

编辑

我查看了 Oracle 的 CardLayout 教程，它看起来很适合我的任务(不包括从外部类创建 JPanel，但没关系)。起初我误解了它，只是在选项卡式 Pane 方面考虑 CardLayout(我不想在我的项目中实现)。

最佳答案

问题来自 JPanelOne 类。它继承了 JPanel，但在构造函数中，您创建了一个新的 JPanel，然后向其添加了一个按钮。如果您这样做:

public class JPanelOne extends JPanel {

   public JPanelOne() {
       JButton button = new JButton("test");
       add(button);
   }
}

它应该如您所愿地工作。

关于java - 将另一个类的 JPanel 添加到 JFrame 中的 JPanel，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12021249/