我试图在这里学习一些Java，但遇到了一个问题。程序应该生成随机的字段形状，但它只生成随机的空形状。
最后一个参数是否填充但似乎没有效果。
这是代码。
public DrawPanel()
{
setBackground( Color.WHITE );
lines = new MyLine[1 + (int)(Math.random() * ((5 - 1) + 1))];
rectangles = new MyRectangle[1 + (int)(Math.random() * ((5 - 1) + 1))];
ovals = new MyOval[1 + (int)(Math.random() * ((5 - 1) + 1))];
// create lines
for ( int count = 0; count < lines.length; count++ )
{
// generate random coordinates
int x1 = randomNumbers.nextInt( 300 );
int y1 = randomNumbers.nextInt( 300 );
int x2 = randomNumbers.nextInt( 300 );
int y2 = randomNumbers.nextInt( 300 );
// generate a random color
Color color = new Color( randomNumbers.nextInt( 256 ),
randomNumbers.nextInt( 256 ), randomNumbers.nextInt( 256 ) );
// add the line to the list of lines to be displayed
lines[count] = new MyLine( x1, y1, x2, y2, color );
// create Rectangles
for ( int countR = 0; countR < rectangles.length; countR++ )
{
// generate random coordinates
int x1R = randomNumbers.nextInt( 300 );
int y1R = randomNumbers.nextInt( 300 );
int x2R = randomNumbers.nextInt( 300 );
int y2R = randomNumbers.nextInt( 300 );
// generate a random color
Color colorR = new Color( randomNumbers.nextInt( 256 ),
randomNumbers.nextInt( 256 ), randomNumbers.nextInt( 256 ) );
// add the rectangles to the list of rectangles to be displayed
rectangles[countR] = new MyRectangle( x1R, y1R, x2R, y2R, colorR, true );
// create Ovals
for ( int countO = 0; countO < ovals.length; countO++ )
{
// generate random coordinates
int x1O = randomNumbers.nextInt( 300 );
int y1O = randomNumbers.nextInt( 300 );
int x2O = randomNumbers.nextInt( 300 );
int y2O = randomNumbers.nextInt( 300 );
// generate a random color
Color colorO = new Color( randomNumbers.nextInt( 256 ),
randomNumbers.nextInt( 256 ), randomNumbers.nextInt( 256 ) );
// add the rectangles to the list of rectangles to be displayed
ovals[countO] = new MyOval( x1O, y1O, x2O, y2O, colorO, true );
} // end Ovals for
} // end Rectangle for
} // end for
} // end DrawPanel constructor
// for each shape array, draw the individual shapes
public void paintComponent( Graphics g )
{
super.paintComponent( g );
// // draw the lines
// for ( MyLine line : lines )
// line.draw( g );
for ( MyRectangle rectangle : rectangles )
{rectangle.draw(g);}
for( MyOval oval : ovals)
{ oval.draw(g); }
for( MyLine line : lines)
{ line.draw(g); }
}
public class MyRectangle {
private int x1 = 0; // x-coordinate of first endpoint
private int y1 = 0; // y-coordinate of first endpoint
private int x2 = 0; // x-coordinate of second endpoint
private int y2 = 0; // y-coordinate of second endpoint
private Color myColor; // color of this shape
boolean filled ; // Boolean flag if shape is filled
public MyRectangle(int x1, int y1, int x2, int y2, Color myColor,
boolean filled) {
super();
this.x1 = x1;
this.y1 = y1;
this.x2 = x2;
this.y2 = y2;
this.myColor = myColor;
this.filled = filled;
}
public MyRectangle() {
super();
setUpperLeftX(0,0);
setUpperLeftY(0,0);
this.myColor = Color.BLACK;
this.filled = false;
}
public int getUpperLeftX(int x1, int x2){
// The upper-left x-coordinate is the smaller of the two x-coordinate values
if(x1 <= x2){
return x1;
}
else{
return x2;
}
}
public void setUpperLeftX(int x1, int x2){
if(x1 >= 0){
this.x1 = x1;
}
else{this.x1 = 0;}
if(x2 >= 0){
this.x2 = x2;
}
else{this.x2 = 0;}
}
public int getUpperLeftY(int x1, int x2){
// the upperleft y-coordinate is the smaller of the two y-coordinate values
if(y1 <= y2){
return y1;
}
else{
return y2;
}
}
public void setUpperLeftY(int x1, int x2){
if(y1 >= 0){
this.y1 = x1;
}
else{this.y1 = 0;}
if(y2 >= 0){
this.y2 = x2;
}
else{this.y2 = 0;}
}
public int getWidth(int x1, int x2){
int width = 0;
// the width is the absolute value of the difference between the two x-coordinate values
width = (x1 - x2);
return Math.abs(width);
}
public int getHeight(){
int height = 0;
// the height is the absolute value of the difference between the two y-coordinate values.
height = (y1 - y2);
return Math.abs(height);
}
public void draw( Graphics g )
{
g.setColor( getMyColor() );
g.drawRect(getX1(), getY1(), getX2(), getY2());
} // end method draw
public int getX1() {
return x1;
}
public void setX1(int x1) {
this.x1 = x1;
}
public int getY1() {
return y1;
}
public void setY1(int y1) {
this.y1 = y1;
}
public int getX2() {
return x2;
}
public void setX2(int x2) {
this.x2 = x2;
}
public int getY2() {
return y2;
}
public void setY2(int y2) {
this.y2 = y2;
}
public Color getMyColor() {
return myColor;
}
public void setMyColor(Color myColor) {
this.myColor = myColor;
}
public boolean isFilled() {
return filled;
}
public void setFilled(boolean filled) {
this.filled = filled;
}
public static void main( String args[] )
{
DrawPanel panel = new DrawPanel();
JFrame application = new JFrame();
application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
application.add( panel );
application.setSize( 600, 600 );
application.setVisible( true );
} // end main