我想知道为什么我不能使用for循环来使用相同的效果,而使用带有actionlistener对象的内部类来刷新图像上的点图。以下是代码:
import java.awt.image.BufferedImage;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Random;
public class MyCanvas
{
JLabel view;
BufferedImage surface;
Random random = new Random();
public void initMyCanvas()
{
surface = new BufferedImage(1000,1000,BufferedImage.TYPE_INT_RGB);
view = new JLabel(new ImageIcon(surface));
Graphics g = surface.getGraphics();
g.setColor(Color.ORANGE);
g.fillRect(0,0,1000,1000);
ActionListener listener=new ActionListener(){
public void actionPerformed(ActionEvent ae){
int[] xLoc = new int[10];
int[] yLoc = new int[10];
System.out.println("drawing..");
Graphics g = surface.getGraphics();
g.setColor(Color.ORANGE);
g.fillRect(0,0,1000,1000);
Random rn=new Random();
for (int ji=0;ji<10;ji++){
xLoc[ji]=rn.nextInt(500);
yLoc[ji]=rn.nextInt(500);
}
drawNodes(xLoc,yLoc,g);
try {
Thread.sleep(1);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
Timer timer = new Timer(1000, listener);
timer.start();
}
public static void main(String[] args)
{
MyCanvas canvas = new MyCanvas();
canvas.initMyCanvas();
JFrame frame = new JFrame();
int vertexes = 0;
vertexes = 10;
int canvasSize = vertexes * vertexes;
frame.setSize(canvasSize, canvasSize);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(canvas.view);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public void drawNodes(int[] x, int[] y, Graphics g)
{
// Treat each location as a 10x10 block. If position 1,1 then go to (5,5) - If position 3,5 then go to (25, 45) eg: (x*10)-5, (y*10)-5
g.setColor(Color.white);
System.out.println(" In drawNodes");
for (int i=0;i<x.length;i++){
g.fillOval(x[i], y[i], 8, 8);
}
g.dispose();
view.repaint();
}
}
与用for循环实现的方法相比,前者多次迭代代码的同一"部分"以创建绘图。
import java.awt.image.BufferedImage;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Random;
public class MyCanvas
{
JLabel view;
BufferedImage surface;
Random random = new Random();
public void initMyCanvas()
{
surface = new BufferedImage(1000,1000,BufferedImage.TYPE_INT_RGB);
view = new JLabel(new ImageIcon(surface));
Graphics g = surface.getGraphics();
g.setColor(Color.ORANGE);
g.fillRect(0,0,1000,1000);
for (int i=0; i<5;i++){
int[] xLoc = new int[10];
int[] yLoc = new int[10];
System.out.println("drawing..");
g.setColor(Color.ORANGE);
g.fillRect(0,0,1000,1000);
Random rn=new Random();
for (int ji=0;ji<10;ji++){
xLoc[ji]=rn.nextInt(500);
yLoc[ji]=rn.nextInt(500);
}
drawNodes(xLoc,yLoc,g);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args)
{
MyCanvas canvas = new MyCanvas();
canvas.initMyCanvas();
JFrame frame = new JFrame();
int vertexes = 0;
vertexes = 10;
int canvasSize = vertexes * vertexes;
frame.setSize(canvasSize, canvasSize);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(canvas.view);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public void drawNodes(int[] x, int[] y, Graphics g)
{
// Treat each location as a 10x10 block. If position 1,1 then go to (5,5) - If position 3,5 then go to (25, 45) eg: (x*10)-5, (y*10)-5
g.setColor(Color.white);
System.out.println(" In drawNodes");
for (int i=0;i<x.length;i++){
g.fillOval(x[i], y[i], 8, 8);
}
g.dispose();
view.repaint();
}
}
我之所以这么问,是因为我正在Xtend中编写等效的实现,作为特定领域语言构建工作的一部分;我在编写内部类和/或实现ActionListener接口方面遇到了问题。再说一遍,这对我自己来说也是一件很好的事情!!
方法2的问题是在EDT中调用循环,因为它会阻塞并且无法绘制组件。阅读Swing Concrency。
1) 摆动Timer
适用于有间隔的绘图。有了定时器,您就不必使用Thread.sleep(1);
。
2) 您可以尝试使用SwingWorker
进行重新绘制。你可以找到很多这样的例子。
3) 也使用paintComponent()
方法中的自定义绘画观看下一个示例并阅读oracle