j2me 中构造方法的问题

来源：互联网发布：买断式回购知乎编辑：程序博客网时间：2024/04/28 19:25

import java.io.IOException;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.game.Sprite;

public class MyGameCanvas extends GameCanvas implements Runnable {

private Graphics g1;

public Image bg;
public Image player;
public Image zidan;

//player的坐标
public int x=80;
public int y=220;
//子弹的坐标
public int x_zidan=110;
public int y_zidan=240;
//npc的坐标
public int x_npc=80;
public int y_npc=0;

//npc的子弹
public int npc_x_zidan=96;
public int npc_y_zidan=40;
//背景图的纵坐标
public int bky;

//npc图片
public Image npc1;

//npc子弹的图片
public Image npc_zidan;

public MyGameCanvas() {

    try {
  bg= Image.createImage("/bg.jpg");
  player=Image.createImage("/player.png");
  zidan=Image.createImage("/zidan.png");
  npc1=Image.createImage("/npc1.png");
        npc_zidan=Image.createImage("/npc_zidan.png");


  new Thread(this).start();
} catch (IOException e) {

  e.printStackTrace();
}
    。。。。。。。。。

编译后

正在通过存储根 d:/我的文档/j2mewtk/2.5.2/appdb/temp.DefaultColorPhone51 来运行
Running with locale: Chinese_People's Republic of China.936
Running in the identified_third_party security domain
java.lang.Error: Unresolved compilation problem:
Implicit super constructor GameCanvas() is undefined. Must explicitly invoke another constructor

at MyGameCanvas.<init>(+9)
at MainApp.<init>(+15)
at java.lang.Class.runCustomCode(+0)
at com.sun.midp.midlet.MIDletState.createMIDlet(+34)
at com.sun.midp.midlet.Scheduler.schedule(+52)
at com.sun.midp.main.Main.runLocalClass(+28)
at com.sun.midp.main.Main.main(+80)
Execution completed.
3392573 bytecodes executed
23 thread switches
1668 classes in the system (including system classes)
17727 dynamic objects allocated (533384 bytes)

这个错误看到了好多都是，但是都没有改对了的，今天花了点时间把它解决了。当继承了GameCanvas后默认要先继承它的父类的构造方法

及：super(true);

添加了这个后就没问题了哈，其实答案很简单但是的却不容易发现！