java - 为什么我的简单 JFrame 显示很奇怪？

Question

我是 Java Swing/AWT 的新手，我在为一个简单的 PopUp 对话框工作后编写了这段代码，该对话框在单击任何 JButtons 时关闭，但显示出真正的不稳定。有人对解决什么以及如何解决有建议吗？

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
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.JTextArea;
import javax.swing.Box.Filler;


public class UpgradePopupWindow extends JPanel implements ActionListener {
//public static UpgradePopupWindow mainWindow;

static final long serialVersionUID = 0;


final String upgrade = "Continue Upgrade";
final String restore = "Restore";

JPanel panels;
JButton flashMe;
JButton helpMe;
JTextArea Message;
JFrame newFrame;
FlasherThread flash;


protected JTextArea addText(String text, boolean visible, int fontStyle) {

    JTextArea textArea = new JTextArea(text);

    textArea.setFont(new Font("SansSerif", fontStyle, 12)); //$NON-NLS-1$

    textArea.setLineWrap(true);
    textArea.setWrapStyleWord(true);
    textArea.setEditable(false);
    textArea.setBackground(Color.DARK_GRAY);
    textArea.setForeground(Color.WHITE);
    textArea.setOpaque(false);
    textArea.setVisible(visible);
    textArea.setAlignmentX(Component.CENTER_ALIGNMENT);

    add(textArea);

    return textArea;
}

private UpgradePopupWindow(JFrame frame, Object ft) {

    flash = (FlasherThread)ft;
    String text = "An error occurred during the attempt to update your  software. We recommend the following: (1) Restore your device to its previous version, (2) back up important data, and then (3) try updating your device again. If you continue with the current update, only your previously backed-up data will be available.";
    addFiller(5);
    addLabel(text, Font.PLAIN, 12);
    //addText(text, true, Font.PLAIN);
    addFiller(20);
    newFrame = frame;
    flashMe = new JButton(upgrade);

    flashMe.setActionCommand("upgrade");
    flashMe.addActionListener(this);
    flashMe.setEnabled(true);
    add(flashMe);


    helpMe = new JButton(restore);
    helpMe.setActionCommand("restore");
    helpMe.addActionListener(this);
    helpMe.setEnabled(true);
    add(helpMe);
    setOpaque(true);
    newFrame.setContentPane(this);
}

protected JLabel addLabel(String text, int fontStyle, int size) {
    JLabel label = new JLabel(text);
    label.setFont(new Font("SansSerif", fontStyle, size)); 
    label.setAlignmentX(Component.CENTER_ALIGNMENT);
    label.setOpaque(false);
    label.setVisible(true);
    //label.setForeground(Color.BLUE);

    add(label);
    return label;
}

protected void addFiller(int size) {
    /*
     * create some space before the progress bar
     */
    Dimension diminsion = new Dimension(size, size);
    Filler filler = new Filler(diminsion, diminsion, diminsion);
    filler.setAlignmentX(Component.CENTER_ALIGNMENT);

    add(filler);
}

public static void createGUI(Object obj) {
    //Create and set up the frame.
   JFrame frame = new JFrame("PopUp Dialog");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setPreferredSize(new Dimension(400, 200));
    //create and setup the content pane
    UpgradePopupWindow popUpContentPane = new UpgradePopupWindow(frame, obj);

    popUpContentPane.setOpaque(true);
    frame.setContentPane(popUpContentPane);

    frame.pack();
    frame.setVisible(true);

}


public void actionPerformed(ActionEvent e) {

    if("restore".equals(e.getActionCommand())) {
        System.out.println("restore button selected");
        flash.setUpgradeRestoreChoice("restore");
        newFrame.dispose();
    } else if ("upgrade".equals(e.getActionCommand())) {
        System.out.println("upgrade button selected");
        flash.setUpgradeRestoreChoice("upgrade");
        newFrame.dispose();
    }
}

}alt text

score 4 · Accepted Answer

您应该使用比默认更好的布局管理器
您应该使用JOptionPane而不是制作自己的选项对话框

score 3 · Accepted Answer

contentPane无需更改框架。您可以将您的添加JPanel到框架中。默认情况下它将填充框架。

JLabel不进行自动换行。

一种选择是手动插入换行符。 JLabel接受 HTML 的子集：

String text = "<html>An error occurred during the attempt to update your  software. <br />We recommend the following:<br />(1) Restore your device to its previous version,<br />(2) back up important data, and then<br />(3) try updating your device again.<br />If you continue with the current update, only your previously backed-up data will be available.</html>";

另一种选择是使用 aJTextArea代替标签。它不接受 HTML，但它可以自动换行，您可以在文本中包含换行符以强制换行。

不要忘记删除边框并使背景透明（调用setOpaque(false)仅适用于某些外观，而不适用于其他外观。）

无论哪种方式，您都需要在 JPanel 上设置布局。

这是一个使用示例GridBagLayout：

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
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.JTextArea;
import javax.swing.WindowConstants;
import javax.swing.Box.Filler;


public class UpgradePopupWindow extends JPanel implements ActionListener {
//public static UpgradePopupWindow mainWindow;

static final long serialVersionUID = 0;


final String upgrade = "Continue Upgrade";
final String restore = "Restore";

JPanel panels;
JButton flashMe;
JButton helpMe;
JTextArea Message;
JFrame newFrame;
FlasherThread flash;


protected JTextArea addText(String text, boolean visible, int fontStyle) {

    JTextArea textArea = new JTextArea(text);

    textArea.setFont(new Font("SansSerif", fontStyle, 12)); //$NON-NLS-1$

    textArea.setLineWrap(true);
    textArea.setWrapStyleWord(true);
    textArea.setEditable(false);
    textArea.setBackground(Color.DARK_GRAY);
    textArea.setForeground(Color.WHITE);
    textArea.setOpaque(false);
    textArea.setVisible(visible);
    textArea.setAlignmentX(Component.CENTER_ALIGNMENT);

    add(textArea);

    return textArea;
}

protected JTextArea addMultiLineLabel(String text, int fontStyle, int fontSize, Object constraints) {

    JTextArea textArea = new JTextArea(text);

    textArea.setFont(new Font("SansSerif", fontStyle, fontSize));

    textArea.setLineWrap(true);
    textArea.setWrapStyleWord(true);
    textArea.setEditable(false);
    textArea.setBackground(new Color(0, 0, 0, 0)); // Zero alpha = transparent background
    textArea.setOpaque(false);
    textArea.setBorder(null);
    textArea.setAlignmentX(Component.CENTER_ALIGNMENT);

    add(textArea, constraints);

    return textArea;
}


private UpgradePopupWindow(JFrame frame, Object ft) {

    super(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    flash = (FlasherThread)ft;
    String text = "An error occurred during the attempt to update your  software.\nWe recommend the following:\n (1) Restore your device to its previous version,\n (2) back up important data, and then\n (3) try updating your device again.\nIf you continue with the current update, only your previously backed-up data will be available.";
    addFiller(5);
    gbc.gridy = 0;
    gbc.gridx = 0;
    gbc.gridwidth = 2;
    gbc.weightx = 1.0;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    addMultiLineLabel(text, Font.PLAIN, 12, gbc);
    addFiller(20);
    newFrame = frame;

    gbc.gridy = 1;
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.NONE;
    flashMe = new JButton(upgrade);
    flashMe.setActionCommand("upgrade");
    flashMe.addActionListener(this);
    flashMe.setEnabled(true);
    add(flashMe, gbc);

    ++ gbc.gridx;
    helpMe = new JButton(restore);
    helpMe.setActionCommand("restore");
    helpMe.addActionListener(this);
    helpMe.setEnabled(true);
    add(helpMe, gbc);
    setOpaque(true);
    newFrame.add(this);
}

protected JLabel addLabel(String text, int fontStyle, int size) {
    JLabel label = new JLabel(text);
    label.setFont(new Font("SansSerif", fontStyle, size)); 
    label.setAlignmentX(Component.CENTER_ALIGNMENT);
    label.setOpaque(false);
    label.setVisible(true);
    //label.setForeground(Color.BLUE);

    add(label);
    return label;
}

protected void addFiller(int size) {
    /*
     * create some space before the progress bar
     */
    Dimension diminsion = new Dimension(size, size);
    Filler filler = new Filler(diminsion, diminsion, diminsion);
    filler.setAlignmentX(Component.CENTER_ALIGNMENT);

    add(filler);
}

public static void createGUI(Object obj) {
    //Create and set up the frame.
   JFrame frame = new JFrame("PopUp Dialog");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setPreferredSize(new Dimension(400, 200));
    //create and setup the content pane
    UpgradePopupWindow popUpContentPane = new UpgradePopupWindow(frame, obj);

    popUpContentPane.setOpaque(true);
    frame.setContentPane(popUpContentPane);

    frame.pack();
    frame.setVisible(true);

}


public void actionPerformed(ActionEvent e) {

    if("restore".equals(e.getActionCommand())) {
        System.out.println("restore button selected");
        flash.setUpgradeRestoreChoice("restore");
        newFrame.dispose();
    } else if ("upgrade".equals(e.getActionCommand())) {
        System.out.println("upgrade button selected");
        flash.setUpgradeRestoreChoice("upgrade");
        newFrame.dispose();
    }
}

}

score 2 · Accepted Answer

我没有看到您使用任何类型的布局。Swing 设计适用于布局，然后用这些布局内的项目填充您的容器。我个人最喜欢使用的布局是MigLayout。

网页上有很多支持。一旦你开始使用布局，当涉及到摇摆设计时，你的生活会变得更加轻松。

java - 为什么我的简单 JFrame 显示很奇怪？

3 回答 3

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