在JPanel上使用滑块绘制二次公式
mun*_*air 2 java swing compiler-errors jpanel
所以,我正在尝试制作一个程序,你可以通过滑块输入二次公式(ax ^ 2 + bx + c).然后在调整A,B和C时绘制图形.
问题:
我希望我用超级油漆写的东西和滑块在一个地方.当我运行滑块时,滑块就位.有正确背景的空间我希望我的图表在面板中,但没有实际的图形.
这是我的驱动程序类:
import java.awt.*;
import javax.swing.*;
public class quadraticslider
{
public static void main (String[] args)
{
JFrame frame = new JFrame ("Quadratic Slider");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new pp109quadraticpanel());
frame.pack();
frame.setVisible(true);
}
}
这是小组类:
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
public class quadraticpanel extends JPanel
{
private JPanel controls, graphPanel;
private JSlider ASlider, BSlider, CSlider;
private JLabel ALabel, BLabel, CLabel;
double A, B, C, x,Y;
//
//SLIDERS YO
//
public quadraticpanel()
{
ASlider = new JSlider (JSlider.HORIZONTAL, 0, 255, 0);
ASlider.setMajorTickSpacing (50);
ASlider.setMinorTickSpacing (10);
ASlider.setPaintTicks (true);
ASlider.setPaintLabels (true);
ASlider.setAlignmentX (Component.LEFT_ALIGNMENT);
BSlider = new JSlider (JSlider.HORIZONTAL, 0, 255, 0);
BSlider.setMajorTickSpacing (50);
BSlider.setMinorTickSpacing (10);
BSlider.setPaintTicks (true);
BSlider.setPaintLabels (true);
BSlider.setAlignmentX (Component.LEFT_ALIGNMENT);
CSlider = new JSlider (JSlider.HORIZONTAL, 0, 255, 0);
CSlider.setMajorTickSpacing (50);
CSlider.setMinorTickSpacing (10);
CSlider.setPaintTicks (true);
CSlider.setPaintLabels (true);
CSlider.setAlignmentX (Component.LEFT_ALIGNMENT);
SliderListener listener = new SliderListener();
ASlider.addChangeListener (listener);
BSlider.addChangeListener (listener);
CSlider.addChangeListener (listener);
ALabel = new JLabel ("a: 0");
ALabel.setAlignmentX (Component.LEFT_ALIGNMENT);
BLabel = new JLabel ("b: 0");
BLabel.setAlignmentX (Component.LEFT_ALIGNMENT);
CLabel = new JLabel ("c: 0");
CLabel.setAlignmentX (Component.LEFT_ALIGNMENT);
controls = new JPanel();
BoxLayout layout = new BoxLayout (controls, BoxLayout.Y_AXIS);
controls.setLayout (layout);
controls.add (ALabel);
controls.add (ASlider);
controls.add (Box.createRigidArea (new Dimension (0, 20)));
controls.add (BLabel);
controls.add (BSlider);
controls.add (Box.createRigidArea (new Dimension (0, 20)));
controls.add (CLabel);
controls.add (CSlider);
graphPanel = new JPanel();
graphPanel.setPreferredSize (new Dimension (500, 500));
graphPanel.setBackground (Color.white);
add (controls);
add (graphPanel);
}
//Here I'm taking the equation, running it through -10 to 10
//It takes the doubles from the equation, converts
//it to int then draws the quadratic formula in dots.
public void paintComponent(Graphics page)
{
super.paintComponent (page);
for ( x=-10; x <= 10; x++)
{
Y = (A*(Math.pow(x,2)))+(B*x)+(C);
int g = (int)Math.round(x);
int h = (int)Math.round(Y);
page.setColor (Color.black);
page.fillOval (g, h, 1, 1);
}
}
public class SliderListener implements ChangeListener
{
///
///Reads the user input via slider.
///
public void stateChanged (ChangeEvent event)
{
A = ASlider.getValue();
B = BSlider.getValue();
C = CSlider.getValue();
ALabel.setText ("a: " + A);
BLabel.setText ("b: " + B);
CLabel.setText ("c: " + C);
}
}
}
使用这些示例JFreeChart可能是有意义的.如图所示在这里,您可以使用动画渲染SwingWorker,而这个例子使用更新的图表JSlider.
附录:您的代码的这种变化可能会指导您前进.注意,
import java.awt.*;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
/** @see https://stackoverflow.com/a/20556929/230513 */
public class QuadraticSlider {
private static final int N = 500;
private static final int A = 1;
private static final int B = 0;
private static final int C = 0;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame("Quadratic Slider");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new QuadraticPanel());
frame.pack();
frame.setVisible(true);
}
});
}
private static class QuadraticPanel extends JPanel {
private Box controls;
private JPanel graphPanel;
private JSlider aSlider, bSlider, cSlider;
private JLabel aLabel, bLabel, cLabel;
double a, b, c, x, y;
public QuadraticPanel() {
aSlider = new JSlider(JSlider.HORIZONTAL, -25, 25, A);
aSlider.setMajorTickSpacing(10);
aSlider.setMinorTickSpacing(5);
aSlider.setPaintTicks(true);
aSlider.setPaintLabels(true);
aSlider.setAlignmentX(Component.LEFT_ALIGNMENT);
bSlider = new JSlider(JSlider.HORIZONTAL, -10, 10, B);
bSlider.setMajorTickSpacing(5);
bSlider.setMinorTickSpacing(1);
bSlider.setPaintTicks(true);
bSlider.setPaintLabels(true);
bSlider.setAlignmentX(Component.LEFT_ALIGNMENT);
cSlider = new JSlider(JSlider.HORIZONTAL, -100, 100, C);
cSlider.setMajorTickSpacing(50);
cSlider.setMinorTickSpacing(10);
cSlider.setPaintTicks(true);
cSlider.setPaintLabels(true);
cSlider.setAlignmentX(Component.LEFT_ALIGNMENT);
SliderListener listener = new SliderListener();
aSlider.addChangeListener(listener);
bSlider.addChangeListener(listener);
cSlider.addChangeListener(listener);
aLabel = new JLabel("a: 0");
bLabel = new JLabel("b: 0");
cLabel = new JLabel("c: 0");
controls = new Box(BoxLayout.Y_AXIS);
controls.add(aLabel);
controls.add(aSlider);
controls.add(Box.createRigidArea(new Dimension(0, 20)));
controls.add(bLabel);
controls.add(bSlider);
controls.add(Box.createRigidArea(new Dimension(0, 20)));
controls.add(cLabel);
controls.add(cSlider);
graphPanel = new JPanel() {
private static final int SCALE = 5;
@Override
public Dimension getPreferredSize() {
return new Dimension(N, N);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for (x = -10; x <= 10; x++) {
y = a * x * x + b * x + c;
g.setColor(Color.black);
int w = (int) (x * SCALE) + N / 2;
int h = (int) (-y * SCALE) + N / 2;
g.fillOval(w, h, 5, 5);
}
}
};
graphPanel.setBackground(Color.white);
add(controls);
add(graphPanel);
listener.stateChanged(null);
}
class SliderListener implements ChangeListener {
@Override
public void stateChanged(ChangeEvent event) {
a = aSlider.getValue() / 5d;
b = bSlider.getValue();
c = cSlider.getValue();
aLabel.setText("a: " + a);
bLabel.setText("b: " + b);
cLabel.setText("c: " + c);
repaint();
}
}
}
}