【发布时间】:2014-04-26 13:41:28
【问题描述】:
我试图操作的代码是paint方法...我试图通过均匀地填充方块来让它显示一个棋盘,但是当我运行程序并将滑块移动到偶数时它给我一列黑色一列空等。 奇数时是棋盘
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
public class Blobs extends JFrame implements ActionListener, ChangeListener {
private MyCanvas canvas = new MyCanvas();
private JSlider sizeSl = new JSlider(0, 20, 0);
private JButton reset = new JButton("RESET");
private int size = 0; // number of lines to draw
public static void main(String[] args) {
new Blobs();
}
public Blobs() {
setLayout(new BorderLayout());
setSize(254, 352);
setTitle("Blobs (nested for)");
sizeSl.setMajorTickSpacing(5);
sizeSl.setMinorTickSpacing(1);
sizeSl.setPaintTicks(true);
sizeSl.setPaintLabels(true);
add("North", sizeSl);
sizeSl.addChangeListener(this);
add("Center", canvas);
JPanel bottom = new JPanel();
bottom.add(reset);
reset.addActionListener(this);
add("South", bottom);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
size = 0;
sizeSl.setValue(0);
canvas.repaint();
}
public void stateChanged(ChangeEvent e) {
size = sizeSl.getValue();
canvas.repaint();
}
private class MyCanvas extends Canvas {
@Override
public void paint(Graphics g) {
int x, y;
int n = 0;
for (int i = 0; i < size; i++) {
//n = 1 + i;
for (int j = 0; j < size; j++) {
n++;
x = 20 + 10 * i;
y = 20 + 10 * j;
//g.fillOval(x, y, 10, 10);
g.drawRect(x, y, 10, 10);
if (n % 2 == 0) {
g.fillRect(x, y, 10, 10);
}
}
}
}
}
}
【问题讨论】:
-
不要将 AWT 组件 (Canvas) 与 Swing 组件 (JFrame) 混为一谈。您应该使用 JPanel 而不是 Canvas,并且应该覆盖它的
paintComponent(Graphics g)方法,而不是它的 paint 方法。
标签: java loops for-loop paintcomponent chessboard.js