[英]Why isn't my JSlider Displaying in my java GUI?
我真的很沮喪,因為GUI顯示但沒有JSlider! 好的,因此GUI應該顯示一個圓JTextfield(在移動滑塊時更新)。 假定文本字段顯示半徑,直徑等,並在移動滑塊時自動更新。 假設一旦移動滑塊,圓形也將增大或減小。 這是我的代碼。 沒有錯誤,可以正常運行並編譯。 可能是我的坐標不對。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import javafx.stage.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextArea;
import javax.swing.SwingConstants;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Circle1 extends JFrame
{
private final CircleCanvas theCanvas;
private final JTextArea display;
public Circle1()
{
super( "Circle1" );
theCanvas = new CircleCanvas();
display = new JTextArea( 4, 30 );
display.setText( "The Radius: " + theCanvas.getRadius() + "\nThe Diameter: " + theCanvas.getDiameter() + "\nThe Area: " + theCanvas.getArea() +
"\nThe Circumference: " + theCanvas.getCircumference() );
getContentPane().add( theCanvas, BorderLayout.CENTER );
getContentPane().add( display, BorderLayout.SOUTH );
setSize( 200, 200 );
setVisible(true);
}
public static void main( String args[] )
{
Circle1 app = new Circle1();
app.addWindowListener(
new WindowAdapter()
{
public void WindowClosing( WindowEvent e )
{
}
}
);
}
void setDiameter(int value) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
}
class CircleCanvas extends JPanel
{
private final int radius;
public CircleCanvas()
{
radius = ( int )( 1 + Math.random() * 100 );
setSize (100, 100);
}
@Override
public void paintComponent( Graphics g )
{ g.drawOval( 0, 0, radius, radius ); }
public int getDiameter()
{ return ( 2 * radius ); }
public int getCircumference()
{ return ( int )( 2 * Math.PI * radius ); }
public int getArea()
{ return ( int )( radius * radius * Math.PI ); }
public int getRadius()
{ return radius; }
}
class SliderFrame extends JFrame
{
private JSlider diameterJSlider;
private Circle1 myPanel;
public SliderFrame()
{
super("HW2");
myPanel = new Circle1();
diameterJSlider = new JSlider(SwingConstants.HORIZONTAL, 0, 300, 10);
diameterJSlider.setMajorTickSpacing(10);
diameterJSlider.setPaintTicks(true);
diameterJSlider.addChangeListener(new ChangeListener()
{
public void stateChanged(ChangeEvent e)
{
myPanel.setDiameter(diameterJSlider.getValue());
}
}
);
add(diameterJSlider, BorderLayout.NORTH);
add(myPanel, BorderLayout.CENTER);
}
}
Circle1
是一個窗口,不能將其添加到另一個窗口,因此您的SliderFrame
已經做錯了,這就是為什么通常不建議直接從諸如JFrame
的頂級容器擴展它,而應該從諸如JPanel
東西開始
因此,您可以從...開始
public class Circle1 extends JPanel {
private final CircleCanvas theCanvas;
private final JTextArea display;
public Circle1() {
setLayout(new BorderLayout());
theCanvas = new CircleCanvas();
display = new JTextArea(4, 30);
display.setText("The Radius: " + theCanvas.getRadius() + "\nThe Diameter: " + theCanvas.getDiameter() + "\nThe Area: " + theCanvas.getArea()
+ "\nThe Circumference: " + theCanvas.getCircumference());
add(theCanvas, BorderLayout.CENTER);
add(display, BorderLayout.SOUTH);
}
void setDiameter(int value) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
class CircleCanvas extends JPanel {
private final int radius;
public CircleCanvas() {
radius = (int) (1 + Math.random() * 100);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawOval(0, 0, radius, radius);
}
public int getDiameter() {
return (2 * radius);
}
public int getCircumference() {
return (int) (2 * Math.PI * radius);
}
public int getArea() {
return (int) (radius * radius * Math.PI);
}
public int getRadius() {
return radius;
}
}
}
然后您可以使用類似...
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Circle1());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
顯示。
然后,您可以將SliderFrame
更改為類似...
public class SliderPane extends JPanel {
private JSlider diameterJSlider;
private Circle1 myPanel;
public SliderPane() {
setLayout(new BorderLayout());
myPanel = new Circle1();
diameterJSlider = new JSlider(SwingConstants.HORIZONTAL, 0, 300, 10);
diameterJSlider.setMajorTickSpacing(10);
diameterJSlider.setPaintTicks(true);
diameterJSlider.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
myPanel.setDiameter(diameterJSlider.getValue());
}
}
);
add(diameterJSlider, BorderLayout.NORTH);
add(myPanel, BorderLayout.CENTER);
}
}
並使用類似...
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new SliderPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
展示它。
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextArea;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Change these two lines to switch between the panels
//frame.add(new Circle1());
frame.add(new SliderPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class Circle1 extends JPanel {
private final CircleCanvas theCanvas;
private final JTextArea display;
public Circle1() {
setLayout(new BorderLayout());
theCanvas = new CircleCanvas();
display = new JTextArea(4, 30);
display.setText("The Radius: " + theCanvas.getRadius() + "\nThe Diameter: " + theCanvas.getDiameter() + "\nThe Area: " + theCanvas.getArea()
+ "\nThe Circumference: " + theCanvas.getCircumference());
add(theCanvas, BorderLayout.CENTER);
add(display, BorderLayout.SOUTH);
}
void setDiameter(int value) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
class CircleCanvas extends JPanel {
private final int radius;
public CircleCanvas() {
radius = (int) (1 + Math.random() * 100);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawOval(0, 0, radius, radius);
}
public int getDiameter() {
return (2 * radius);
}
public int getCircumference() {
return (int) (2 * Math.PI * radius);
}
public int getArea() {
return (int) (radius * radius * Math.PI);
}
public int getRadius() {
return radius;
}
}
}
public class SliderPane extends JPanel {
private JSlider diameterJSlider;
private Circle1 myPanel;
public SliderPane() {
setLayout(new BorderLayout());
myPanel = new Circle1();
diameterJSlider = new JSlider(SwingConstants.HORIZONTAL, 0, 300, 10);
diameterJSlider.setMajorTickSpacing(10);
diameterJSlider.setPaintTicks(true);
diameterJSlider.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
myPanel.setDiameter(diameterJSlider.getValue());
}
}
);
add(diameterJSlider, BorderLayout.NORTH);
add(myPanel, BorderLayout.CENTER);
}
}
}
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