Question

关于Java的Graphics2D的问题，我画的直线为什么不显示出来

package java_draw;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
public class draw_line extends JFrame{
public draw_line(){
this.setVisible(true);
this.setBounds(300, 300, 300, 300);
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
init();
}

void init(){
BufferedImage image=new BufferedImage(300,300,BufferedImage.TYPE_INT_RGB);
Graphics2D g=(Graphics2D)image.getGraphics();
g.setColor(Color.red);
g.drawLine(0, 0, 300, 300);

}
}

Answer 1

因为你没有画在窗口上

追问

怎么改啊？？

追答

this.getGraphics();