我想问一下为什么这个窗口的实现不会显示代码
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.JFrame;
public class exp11_12 extends JFrame{
Toolkit tk;
Image img;
public exp11_12() {
setTitle("显示图像");
setSize(400,200);
setVisible(true);
Dimension size =Toolkit.getDefaultToolkit().getScreenSize();
setLocation((size.width-getWidth())/2,(size.height-getHeight())/2);
tk=getToolkit();
img=tk.getImage("C:\\桌面\\Pr\\1.jpg");
}
public void paint(Graphics g) {
g.drawImage(img, 50, 50,this);
}
public static void main(String[] args) {
new exp11_12();
}
}
调试下img=tk.getImage("C:\桌面\Pr\1.jpg");这一行,之后img是否有值