Question

java怎么画不上去图片

/* * To change this template, choose Tools | Templates * and open the template in the editor. */package mainGame;import java.awt.Graphics;import java.awt.Image;import java.awt.Toolkit;import javax.swing.JFrame;/** * * @author Administrator */public class draw1 extends JFrame{ Image a; public draw1(){ Toolkit toolkit=this.getToolkit(); toolkit.getImage("Circle_black.png"); toolkit.prepareImage(a, 200, 200, this); } public void paint(Graphics g) { g.drawImage(a, 200, 200, 50, 50, this); } public static void main(String[] args) { draw1 f=new draw1(); f.setSize(300, 200); f.setVisible(true); }}

Answer 1

我看了你的程序，只要
一、把toolkit.getImage("Circle_black.png");改成a=toolkit.getImage("Circle_black.png");
二、把g.drawImage(a, 200, 200, 50, 50, this);改成g.drawImage(a, 0, 0, 200, 200, this);
就行了。完整的程序如下：
/* * To change this template, choose Tools | Templates * and open the template in the editor. */
package mainGame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.JFrame;
/** * * @author Administrator */
public class draw1 extends JFrame{
Image a;
public draw1(){
Toolkit toolkit=this.getToolkit();
a=toolkit.getImage("Circle_black.png");
toolkit.prepareImage(a, 200, 200, this);
}
public void paint(Graphics g) {
g.drawImage(a, 0, 0, 200, 200, this);
}
public static void main(String[] args) {
draw1 f=new draw1();
f.setSize(300, 200);
f.setVisible(true);
}
}

Answer 2

那肯定画不了的，你调用的a根本就没赋值，从头到尾就是一个空对象。自己编的时候看看API