关于你的评论改变添加公共显示(图形g)
[链接] http://www3.canyons.edu/Faculty/biblej/project6.html
1.)Project6类必须扩展JFrame类2.)Project6构造函数必须设置GUI窗口 . 3.)一种新的抽象方法:public void display(Graphics g);应该添加到基类和派生类中.4 . 必须使用paintComponent方法设置自定义JPanel . )新显示(Graphics g)方法必须在GUI窗口上绘制形状并从循环中调用在paintComponent方法中
public class Project6 extends JFrame {
//project6 constructor without parameters to set up new JFrame
public Project6() {
add(new NewPanel());
}
class NewPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
//所以我需要在这里添加Graphics g吗?或没有?
for(int i = 0; i < thearray.length && thearray[i] != null; i++) {
thearray[i].display(**Graphics g**);
}}}
public static void main (String [] args) {
JFrame frame = new JFrame();
frame.setSize(800, 700);
frame.setTitle("Shapes");
frame.setLocationRelativeTo(null); //Center Frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
这是一个类,例如,我是否像这样添加到最后?我是否需要向Shape父类添加公共抽象void显示(Graphics g)?它将如何在project6类中调用?
public class Rectangle extends Shape {
private int width;
private int height;
public Rectangle() {
setWidth(0);
setHeight(0);
setXPos(0);
setYPos(0);}
public Rectangle(int xPos, int yPos, int height, int width) {
setWidth(xPos);
setHeight(yPos);
setXPos(height);
setYPos(width);}
public int getWidth() {
return width;}
public void setWidth(int width) {
this.width = width;}
public int getHeight() {
return height;}
public void setHeight(int height) {
this.height = height;}
@Override
public void display() {
System.out.println("Rectangle: (" + getXPos() + ", " + getYPos() + ") " + " Height: " + height + " Width: " + width);}
@Override
public void display(Graphics g) {
g.drawRect(getXPos(), getYPos(), width, height); }
1 回答
您没有正确执行此步骤,因为我注意到,当
display
打算使用参数时,您正在调用thearray[i].display();
.如果正确创建
display
方法,那么您将获得可以使用的Graphics对象,例如: