从 JSlider 向 JLabel 显示 RGB

Question

我正在尝试编写一个程序，从每个值的滑块中获取红色、绿色和蓝色的颜色值，然后将其显示为 rgb 值。我不确定如何从三个滑块中提取 rgb 值，但我认为我很接近。我不知道如何将数据发送到 JLabel，或者我是否使用正确的方法来获取 rgb。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.GridLayout;
import java.awt.image.ColorModel;
import javax.swing.JSlider;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class MyColorChooser extends JFrame {

public final JSlider colorRed;
public static JSlider colorBlue;
public static JSlider colorGreen;
public static JLabel rgbValue;
public static JLabel green;
public static JLabel blue;
public int r;
public int g;
public int b;
Color c;

public Color getC() {
    return c;
}

public void setC(Color c) {
    this.c = new Color(r, g, b);
}

public MyColorChooser() {
    super("Slider Demo");

    JPanel Panel1 = new JPanel(new BorderLayout());
    JPanel Panel2 = new JPanel(new BorderLayout());
    JPanel Panel3 = new JPanel(new BorderLayout());
    JPanel Panel4 = new JPanel(new BorderLayout());

    rgbValue = new JLabel("RGB Value");
    colorRed
            = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 0);
    colorBlue
            = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 0);
    colorGreen
            = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 0);
    colorRed.setMajorTickSpacing(5); // create tick every 10
    colorRed.setPaintTicks(true);
    colorRed.setPaintLabels(true);// paint ticks on slider
    colorBlue.setMajorTickSpacing(5); // create tick every 10
    colorBlue.setPaintTicks(true);
    colorBlue.setPaintLabels(true);//
    colorGreen.setMajorTickSpacing(5); // create tick every 10
    colorGreen.setPaintTicks(true);
    colorGreen.setPaintLabels(true);//

    colorRed.setLabelTable(colorRed.createStandardLabels(10));
    colorGreen.setLabelTable(colorGreen.createStandardLabels(10));
    colorBlue.setLabelTable(colorBlue.createStandardLabels(10));

    Panel1.add(colorRed);
    Panel2.add(colorGreen);
    Panel3.add(colorBlue);
    Panel4.add(rgbValue);

    setLayout(new GridLayout(10, 1));
    add(Panel1);
    add(Panel2);
    add(Panel3);
    add(Panel4);

    colorGreen.addChangeListener(new ChangeListener() {
        @Override
        public void stateChanged(ChangeEvent e) {
            JSlider colorGreen = (JSlider) e.getSource();
            g = colorGreen.getValue();; //To change body of generated methods, choose Tools | Templates.
        }
    });

    colorRed.addChangeListener(
            new ChangeListener() {

        @Override
        public void stateChanged(ChangeEvent e) {

            JSlider colorRed = (JSlider) e.getSource();
            r = colorRed.getValue();

        }
    });

    colorBlue.addChangeListener(
            new ChangeListener() {
        @Override
        public void stateChanged(ChangeEvent e) {
            JSlider colorBlue = (JSlider) e.getSource();
            b = colorBlue.getValue();//To change body of generated methods, choose Tools | Templates.

        }

    });

}

}

Answer 1

I can't figure out how to send the data to the JLabel or if I'm using the correct approach to get the rgb

好吧，如果你想改变文本，你需要在标签上调用 setText(....) 方法。

所以这意味着您需要创建一个类似于 updateLabel() 的方法，您可以从 3 个侦听器中的每个侦听器中调用该方法。在该方法中，您将获得 r、g、b 变量的值，并按照您希望文本在标签中显示的方式格式化字符串。

Answer 2

如果我明白你在这里想要什么...你想从 3 个 JSliders 中获取值，可能是 0-255，然后将其转换为 JLabel 上的 background/foreground 颜色？如果是这样，那么您将需要在每次 JSlider 调用时都有 changeListener rgbValue.setForeground(new Color(r, g, b));。如果您希望 JLabel 显示颜色的十六进制表示，那么它将是

rgbValue.setText("RGB Value: #" + String.format("%02X", r) + String.format("%02X", g) + String.format("%02X", b));

从 JSlider 向 JLabel 显示 RGB

displaying RGB to a JLabel from a JSlider

java

swing

awt

listener

jslider