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我目前正在爲學校開發一個程序。我們必須製作一個Applet，並選擇了JApplet。出於某種原因，我用來顯示特定字符串的面板不會顯示。這可能是什麼問題？請指向正確的方向。另外，我看了一些教程，一些人建議我有「開始」，「停止」和「破壞」方法，有些則沒有。這些方法中的任何一種都會影響我的JPanel爲什麼不顯示圖形？Java圖形JApplet
謝謝
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Shape extends JApplet {
/**
*
*/
private static final long serialVersionUID = 1L;
// making the radiobuttons for the shape choices
JRadioButton squareButton = new JRadioButton("Square",true);
JRadioButton ovalButton = new JRadioButton("Oval",false);
JRadioButton rectangleButton = new JRadioButton("Rectangle",false);
JRadioButton triangleButton = new JRadioButton("Triangle",false);
// making radiobuttons for the color choices
JRadioButton redButton = new JRadioButton("Red",true);
JRadioButton blueButton = new JRadioButton("Blue",false);
JRadioButton greenButton = new JRadioButton("Green",false);
JRadioButton yellowButton = new JRadioButton("Yellow",false);
// making buttons draw and animate
JButton drawButton = new JButton("Draw!");
JButton animateButton = new JButton("Animate!");
// making JTextFields for length and width
JTextField lengthField = new JTextField("Enter a length",15);
JTextField widthField = new JTextField("Enter a width",15);
// making JPanel, in which the radiobuttons will go01
JPanel shapePanel = new JPanel();
JPanel colorPanel = new JPanel();
JPanel buttonPanel = new JPanel();
JPanel textPanel = new JPanel();
drawPanel dPanel;
ButtonGroup shapeGroup = new ButtonGroup();
ButtonGroup colorGroup = new ButtonGroup();
// variables that will dictates the shape, size and color
int length = 200;
int width = 200;
Color color = Color.RED;
String shape = "square";
public void init() {
setLayout(new FlowLayout()); // setting layout for the applet
setSize(680,480);
// setting the layout for the shapePanel - gridlayout 2 rows, 2 cols and space of 5
shapePanel.setLayout(new GridLayout(2,2,5,5));
// adding a border to the shapePanel to indicate to the user what it does "titledBorder"
shapePanel.setBorder(BorderFactory.createTitledBorder("Choose a shape"));
// setting layout for the color panel - gridlayout 2 rows, 2 cols and space of 5
colorPanel.setLayout(new GridLayout(2,2,5,5));
// adding a border to the colorPanel to indicate to the user what it does "titledBorder"
colorPanel.setBorder(BorderFactory.createTitledBorder("Choose a color"));
// setting the layout for the buttonPanel - gridlayout 1 row, 2 cols and space of 5
buttonPanel.setLayout(new GridLayout(1,2,5,5));
// adding a color border
buttonPanel.setBorder(BorderFactory.createLineBorder(Color.red, 2));
// setting the layout of the textField - gridlayout 1 row, 2 cols and space of 5
textPanel.setLayout(new GridLayout(1,2,5,5));
// adding some attributes for lengthField and widthField
lengthField.setFont(new Font("Arial",Font.PLAIN,12));
lengthField.setForeground(new Color(150,150,150));
widthField.setFont(new Font("Arial",Font.PLAIN,12));
widthField.setForeground(new Color(150,150,150));
// using shapegroup to organize the JRadioButtons
shapeGroup.add(squareButton);
shapeGroup.add(ovalButton);
shapeGroup.add(rectangleButton);
shapeGroup.add(triangleButton);
// using colorgroup to organize the color radiobuttons
colorGroup.add(redButton);
colorGroup.add(blueButton);
colorGroup.add(greenButton);
colorGroup.add(yellowButton);
// add the shape buttons to the panel so they appear in a square form
shapePanel.add(squareButton);
shapePanel.add(ovalButton);
shapePanel.add(rectangleButton);
shapePanel.add(triangleButton);
// adding color buttons to the color panel
colorPanel.add(redButton);
colorPanel.add(blueButton);
colorPanel.add(greenButton);
colorPanel.add(yellowButton);
// adding jbuttons
buttonPanel.add(drawButton);
buttonPanel.add(animateButton);
// adding textfields to the textPanel
textPanel.add(lengthField);
textPanel.add(widthField);
dPanel = new drawPanel();
// adding panels to the applet
add(shapePanel);
add(colorPanel);
add(buttonPanel);
add(textPanel);
add(dPanel);
// adding focus listener to lengthField and widthField
lengthField.addFocusListener(new FocusListener() {
public void focusGained(FocusEvent e) {
lengthField.setText("");
lengthField.setForeground(Color.black);
}
public void focusLost(FocusEvent e) {}
});
widthField.addFocusListener(new FocusListener() {
public void focusGained(FocusEvent e) {
widthField.setText("");
widthField.setForeground(Color.black);
}
public void focusLost(FocusEvent e) {}
});
drawButton.addActionListener(new drawListener());
}
// when the person presses paint, this will be executed to paint the specific shape, color with the width and length
class drawListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
int mylength = 5;
int mywidth = 5;
try {
mylength = Integer.parseInt(lengthField.getText());;
mywidth = Integer.parseInt(widthField.getText());;
}catch(Exception ex) {
JOptionPane.showMessageDialog(null,""+ex,"",JOptionPane.ERROR_MESSAGE);
}
if((mylength > 200 || mylength < 5)) {
JOptionPane.showMessageDialog(null, "Please make sure the number is above 5 and less than 200",
"Invalid length message", JOptionPane.ERROR_MESSAGE);
}else if((mywidth > 200 || mywidth < 5)) {
JOptionPane.showMessageDialog(null, "Please make sure the number is above 5 and less than 200",
"Invalid width message", JOptionPane.ERROR_MESSAGE);
}else {
length = mylength;
width = mywidth;
// checking which color button is selected
if(redButton.isSelected()) {
color = Color.RED;
}else if(blueButton.isSelected()) {
color = Color.BLUE;
}else if(greenButton.isSelected()) {
color = Color.GREEN;
}else if(yellowButton.isSelected()) {
color = Color.YELLOW;
}
// checking which shape has been selected
if(rectangleButton.isSelected()) {
shape = "rectangle";
}else if(triangleButton.isSelected()) {
shape = "triangle";
}else if(ovalButton.isSelected()) {
shape = "oval";
}else if(squareButton.isSelected()) {
shape = "square";
}
//System.out.printf("%3d %3d %s %s \n",length,width,shape,color);
}
}
}
// This will be used to do the painting
class drawPanel extends JPanel {
private static final long serialVersionUID = 1L;
//Paint Method
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.black);
g2.drawString("My awesome string", 200, 200);
}
}
}
你先生，是救命的人。非常感謝你。我想知道是否可以請刪除此代碼，因爲這是針對一個項目的，我不想讓其他人複製它。再一次感謝你。 – 2012-04-02 22:38:59
*「我想知道您是否可以刪除此代碼，」*我可以，但不會。這不是SO的工作原理。如果您需要私人解決方案，請聘請私人導師。 – 2012-04-02 22:41:20
@ user681159：所以你說實際上你借用這段代碼是可以的，但是對於其他人來說這樣做不好嗎？那是什麼？你比其他誰可以從中受益更好或更重要嗎？或者是你想爲你的任務提交這段代碼的原因，就像你寫了它一樣。無論哪種方式，這太臭了。 – 2012-04-02 22:46:10