我开始介绍一些基本的Java2D示例 - 特别是在AWT下 - 遵循“计算机图形学Java2D / Java3D简介”一书的第一个例子我编写了以下两个类,一个作为“主”类:
package com.example.test;
public class Test {
public static void main( String[] args ) {
MyChart terminal = new MyChart();
terminal.setTitle("The first Java 2D program");
terminal.setSize(350,80);
terminal.setVisible(true);
}
}
另一个扩展AWT框架:
package com.example.test;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class MyChart extends Frame {
public void MyChart() {
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e) {
dispose();
}
});
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.drawString("Hello world!", 30, 50);
};
}
这会在屏幕上生成预期的“Hello World”窗口,但是当我单击关闭按钮(Windows 10)时,没有任何反应。我试图弄清楚在添加监听器时我做错了什么但没有成功。
任何提示或建议甚至进一步调试都受到欢迎。
我在Java下:1.8.0_191和Windows 10如上所述。
你没有在主类中调用MyChart
函数。下面的代码工作正常。
public class Test {
public static void main( String[] args ) {
System.out.println("Terminal Group");
MyChart terminal = new MyChart();
terminal.MyChart();//I added this.
terminal.setTitle("The first Java 2D program");
terminal.setSize(350,80);
terminal.setVisible(true);
}
}
public class MyChart extends Frame {
public void MyChart() {
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e) {
dispose();
}
});
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.drawString("Hello world!", 30, 50);
};
}
构造函数定义错误,void
存在且必须删除。
原始代码(WRONG构造函数,使用void):
public void MyChart() {
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e) {
dispose();
}
});
}
更正代码(无空格):
public MyChart() {
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e) {
dispose();
}
});
}