我似乎无法找到我希望是一个简单问题的答案。我正在用 Java 制作一个 GUI，让用户从列表中选择一个形状，输入所需的尺寸，然后当他们按下 Draw 时，它会在 JPanel 中绘制形状。但是，我尝试了多种不同的方法来使其发挥作用，但形状从未出现。这是我目前所拥有的。
在用户选择形状后，运行 UserInterface.java 中的以下代码
case "Circle":
choiceLabelText.setText("You have selected " + choice);
Circle myCircle = new Circle(0,0,0);
try {
Double r = Double.parseDouble(Dim1_Box.getText());
Double area = myCircle.getArea(r);
AreaVolume.setText(String.valueOf(area));
ShapePanel.add(new DrawCircle(ShapePanel.getWidth(), ShapePanel.getHeight()));
ShapePanel.revalidate();
ShapePanel.repaint();
userInterface.pack();
userInterface.repaint();
}
catch(NumberFormatException e) {
break;
}
break;
它调用 DrawCircle 类，它很简单
public class DrawCircle extends JPanel {
int x = 0;
int y = 0;
int w, h;
public DrawCircle(int w, int h) {
System.out.println("DrawCircle was called");
this.w = w;
this.h = h;
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.red);
g2.fillOval(x, y, w, h);
}
}
这里是完整的 UserInterface.java 文件
public class UserInterface extends JFrame {
JFrame userInterface;
// Variables declaration - do not modify//GEN-BEGIN:variables
private java.awt.TextField AreaVolume;
private javax.swing.JLabel ChooseShapeText;
private java.awt.TextField Dim1_Box;
private java.awt.Label Dim1_Label;
private java.awt.TextField Dim2_Box;
private java.awt.Label Dim2_Label;
private java.awt.TextField Dim3_Box;
private java.awt.Label Dim3_Label;
private java.awt.TextField Dim4_Box;
private java.awt.Label Dim4_Label;
private java.awt.Button DrawButton;
private javax.swing.JPanel ShapePanel;
private java.awt.Label choiceLabelText;
private java.awt.Label label1;
private java.awt.Choice shapeSelection;
// End of variables declaration//GEN-END:variables
public UserInterface() {
this.userInterface = new JFrame();
initComponents(userInterface);
}
private JFrame getJFrame(){
return this.userInterface;
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
private void initComponents(JFrame userInterface) {
ShapePanel = new javax.swing.JPanel();
shapeSelection = new java.awt.Choice();
ChooseShapeText = new javax.swing.JLabel();
choiceLabelText = new java.awt.Label();
DrawButton = new java.awt.Button();
Dim1_Box = new java.awt.TextField();
Dim2_Box = new java.awt.TextField();
Dim3_Box = new java.awt.TextField();
Dim4_Box = new java.awt.TextField();
Dim1_Label = new java.awt.Label();
Dim2_Label = new java.awt.Label();
Dim3_Label = new java.awt.Label();
Dim4_Label = new java.awt.Label();
AreaVolume = new java.awt.TextField();
label1 = new java.awt.Label();
userInterface.setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
userInterface.setResizable(false);
/* vvv THE JPANEL I AM WORKING WITH */ ShapePanel.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));
javax.swing.GroupLayout ShapePanelLayout = new javax.swing.GroupLayout(ShapePanel);
ShapePanel.setLayout(ShapePanelLayout);
ShapePanelLayout.setHorizontalGroup(
ShapePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
ShapePanelLayout.setVerticalGroup(
ShapePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 446, Short.MAX_VALUE)
);
/* ^^^ THE JPANEL I AM WORKING WITH */
shapeSelection.add("--- Choose Shape ---");
shapeSelection.add("Circle");
shapeSelection.add("Square");
shapeSelection.add("Triangle");
shapeSelection.add("Rectangle");
shapeSelection.add("Sphere");
shapeSelection.add("Cube");
shapeSelection.add("Cone");
shapeSelection.add("Cylinder");
shapeSelection.add("Torus");
shapeSelection.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
shapeSelectionItemStateChanged(evt);
}
});
ChooseShapeText.setFont(new java.awt.Font("sansserif", 1, 14)); // NOI18N
ChooseShapeText.setText("Choose Shape");
DrawButton.setLabel("Draw!");
DrawButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
DrawButtonActionPerformed(evt);
}
});
Dim1_Label.setText("Radius");
label1.setText("Area");
GroupLayout layout = new javax.swing.GroupLayout(userInterface.getContentPane());
userInterface.getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(ChooseShapeText)
.addComponent(choiceLabelText, javax.swing.GroupLayout.PREFERRED_SIZE, 277, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(Dim2_Label, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(Dim3_Label, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(Dim4_Label, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(Dim4_Box, javax.swing.GroupLayout.PREFERRED_SIZE, 97, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(Dim2_Box, javax.swing.GroupLayout.PREFERRED_SIZE, 97, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createSequentialGroup()
.addComponent(Dim3_Box, javax.swing.GroupLayout.PREFERRED_SIZE, 97, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 196, Short.MAX_VALUE)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, 55, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addGroup(layout.createSequentialGroup()
.addComponent(Dim1_Label, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(Dim1_Box, javax.swing.GroupLayout.PREFERRED_SIZE, 97, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(DrawButton, javax.swing.GroupLayout.PREFERRED_SIZE, 101, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(AreaVolume, javax.swing.GroupLayout.PREFERRED_SIZE, 97, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addComponent(shapeSelection, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGap(10, 10, 10))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(ShapePanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(10, 10, 10)
.addComponent(ShapePanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(ChooseShapeText)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(shapeSelection, javax.swing.GroupLayout.PREFERRED_SIZE, 39, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(choiceLabelText, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(Dim1_Box, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(133, 133, 133)
.addComponent(Dim1_Label, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createSequentialGroup()
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(Dim3_Box, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(Dim2_Label, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(AreaVolume, javax.swing.GroupLayout.PREFERRED_SIZE, 38, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(202, 202, 202)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(Dim2_Box, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(layout.createSequentialGroup()
.addGap(0, 0, Short.MAX_VALUE)
.addComponent(Dim3_Label, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(26, 26, 26)
.addComponent(Dim4_Box, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(Dim4_Label, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(60, 60, 60)
.addComponent(DrawButton, javax.swing.GroupLayout.PREFERRED_SIZE, 62, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(55, 55, 55))
);
userInterface.pack();
}// </editor-fold>//GEN-END:initComponents
/* vvv THE METHOD CALLED WHEN THE USER MAKES A SELECTION */
private void shapeSelectionItemStateChanged(java.awt.event.ItemEvent evt) {
String choice = shapeSelection.getSelectedItem();
switch (choice) {
case "Circle":
choiceLabelText.setText("You have selected " + choice);
Circle myCircle = new Circle(0,0,0);
try {
Double r = Double.parseDouble(Dim1_Box.getText());
Double area = myCircle.getArea(r);
AreaVolume.setText(String.valueOf(area));
int x = 25;
int y = 25;
//int radius = 5;
//Graphics2D circle = new Graphics2D();
//this.userInterface.getContentPane().add(label1)
//Graphics circle;
//int x = ShapePanel.getWidth()/2;
//int y = ShapePanel.getHeight()/2;
//int radius = 5;
//DrawCircle circle = new DrawCircle(1,1,1,1);
//ShapePanel.add(circle);
//ShapePanel.validate();
//ShapePanel.revalidate();
//ShapePanel.repaint();
//this.userInterface.revalidate();
//this.userInterface.repaint();
//ShapePanel.paintComponents(circle);
//circle.drawOval(x, y, radius, radius);
DrawCircle newJPanel = new DrawCircle(x, y, x, y);
newJPanel.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));
//ShapePanel.setForeground(new java.awt.Color(0, 0, 0));
//int x = ShapePanel.getWidth()/2;
//int y = ShapePanel.getHeight()/2;
//ShapePanel.add(new DrawCircle(x, y, 50, 50));
javax.swing.GroupLayout ShapePanelLayout = new javax.swing.GroupLayout(newJPanel);
newJPanel.setLayout(ShapePanelLayout);
ShapePanelLayout.setHorizontalGroup(
ShapePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
ShapePanel = newJPanel;
userInterface.revalidate();
userInterface.pack();
userInterface.repaint();
//userInterface.add(new DrawCircle(x, y, x, y));
}
catch(NumberFormatException e) {
break;
}
break;
case "Square":
choiceLabelText.setText("You have selected " + choice);
//Square mySquare = new Square(2,0,0);
//mySquare.getArea();
myCircle = new Circle(0,0,0);
try {
Double r = Double.parseDouble(Dim1_Box.getText());
Double area = myCircle.getArea(r);
AreaVolume.setText(String.valueOf(area));
}
catch(NumberFormatException e) {
break;
}
break;
default:
break;
}
}
/* ^^^ THE METHOD CALLED WHEN THE USER MAKES A SELECTION */
private void DrawButtonActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_DrawButtonActionPerformed
// TODO add your handling code here:
}//GEN-LAST:event_DrawButtonActionPerformed
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new UserInterface().getJFrame().setVisible(true);
}
});
}
}
任何有用的指针将不胜感激！
编辑：通过删除我所有的测试内容来帮助简化代码