Question

当我运行它时，会显示一个空标题栏。我只是希望能够从那里看到组件和工作，但没有显示任何内容。该对话框旨在允许用户通过移动滑块选择颜色，然后返回到主页面的颜色。

import java.awt.*;
import javax.swing.*;

public class ColourDialog extends JDialog
{
    String colorNames[] = {"Red: ", "Green: ", "Blue: "};
    Label labels[] = new Label[3];
    JSlider slider[]= new JSlider[3];
    Label lb;
    static ColourDialog d;

    public void ColourDialog()
    {
        setModal(true);
        Container c = getContentPane();
        c.setLayout(new BorderLayout());
        JPanel sliderPanel = new JPanel();
        sliderPanel.setLayout(new GridLayout(0, 1));

        for (int i = 0; i < slider.length;  i++)
        {
            labels[i] = new Label(colorNames[i] + 255);

            sliderPanel.add(labels[i]);
            slider[i] = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 255);
            slider[i].setMinorTickSpacing(10);
            slider[i].setMajorTickSpacing(50);
            slider[i].setPaintTicks(true);
            slider[i].setPaintLabels(true);

            sliderPanel.add(slider[i]);
            //slider[i].addChangeListener(this);
        }

        lb = new Label("Colour");

        c.add(sliderPanel, BorderLayout.CENTER);
        c.add(lb, BorderLayout.SOUTH);

        setSize(500, 450);
        setLocation(200,200);
        setTitle("Colour Dialog");
    }

    public static Color showDialog()
    {
        if (d == null)
        d = new ColourDialog();

        d.show();

        //return new Color(red,green,blue);
        return new Color(0,0,0);
    }

    public static void main(String args[])
    {
        ColourDialog.showDialog();
    }
}

Answer 1

我认为您已查看JColorChooser，此JComponent可以返回选定的Color

在那里，我无法为JSlider

找出正确的定义和初始化

修改

从使用公共静态Color showDialog（）的扩展JDialog结尾开始有很多错误，它返回带有ColourDialog（）初始化的空容器拼写错误

enter image description here

import java.awt.*;
import javax.swing.*;

public class ColourDialog {

    private JDialog dialog = new JDialog();
    private String colorNames[] = {"Red: ", "Green: ", "Blue: "};
    private Label labels[] = new Label[3];
    private JSlider slider[] = new JSlider[3];
    private Label lb;

    public ColourDialog() {
        JPanel sliderPanel = new JPanel();
        sliderPanel.setLayout(new GridLayout(0, 1));
        for (int i = 0; i < slider.length; i++) {
            labels[i] = new Label(colorNames[i] + 255);
            sliderPanel.add(labels[i]);
            slider[i] = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 255);
            slider[i].setMinorTickSpacing(10);
            slider[i].setMajorTickSpacing(50);
            slider[i].setPaintTicks(true);
            slider[i].setPaintLabels(true);
            sliderPanel.add(slider[i]);
        }
        lb = new Label("Colour");
        dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
        dialog.setModal(true);
        dialog.add(sliderPanel, BorderLayout.CENTER);
        dialog.add(lb, BorderLayout.SOUTH);
        dialog.pack();
        dialog.setLocation(200, 200);
        dialog.setTitle("Colour Dialog");
        dialog.setVisible(true);
    }

    public static void main(String args[]) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                ColourDialog colourDialog = new ColourDialog();
            }
        });
    }
}

Answer 2

我认为这可能是因为你说“public void ColourDialog（）”这是一个无效的构造函数。尝试摆脱“虚空”，然后再试一次。

Answer 3

您永远不会调用ColorDialog（）方法。这是一个提到“使用小写字母开始方法”的好地方。要修复代码：

变化：

    d = new ColourDialog();

要：

    d = new ColourDialog(); 
    d.ColourDialog();

将组件添加到JDialog

3 个答案: