hello all , first time using greenfoot. i managed to get the aliens to move to the right and left but when once they touch the left wall they dont go back right , they just keep going left, ive tired if statements and loops , nothings working.
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.List;
/**
* Write a description of class SpaceShip here.
*
* @author Aditya Wagh
* @version 10
*/
public class Invader extends Actor
{
private int speed = 1;
private double heading = 0 ;
private int health;
private Invader Invaders;
public int shouldMove = 0;
public int fireBullet;
public int chance = 1;
public GreenfootImage image1;
public GreenfootImage image2;
private int aliensKilled;
// instant variables here to indivate 2 different images, so that you can use these
// in flipimage method
// you need to have a constructor with 2 image parameters
public void move() {
double angle = Math.toRadians(heading); // change heading to 90 degrees to move down
int x = (int) Math.round(getX() + Math.cos(angle) * speed);
int y = (int) Math.round(getY() + Math.sin(angle) * speed); // can change the speed
setLocation(x, y);
}
public void gotHit(){
// decrease health point.
}
public void destroy(){
Greenfoot.playSound("explosion.wav");
}
public void fireBullet(){
if (shouldMove == 1){
fireBullet = Greenfoot.getRandomNumber(100);
if (fireBullet <= chance) {
getWorld().addObject(new InvaderBullet(), getX(), getY()+5);
}
}
}
public void act(){
flipImage();
fireBullet();
destroy();
}
public void flipImage(){
//TODO
if (getImage()== image1){
setImage(image2);
}
else {
setImage(image1);
}
}
public void moveDown(){
heading = 90;
speed = 1;
move();
// 1. change the heading to 90 deg
// 2. change the speed
// 3. call move()
}
public void reverseDirection(){
heading = 180;
//move();
//move right, heading = 0 , move left = 180
}
public int getHealth(){
//TODO
return 3;
}
public int getPoints(){
//TODO
// i
return 10;
}
public boolean atWorldEdge() {
if (getX() < 40 || getX() > getWorld().getWidth() - 41) {
return true;
}
if (getY() < 40 || getY() > getWorld().getHeight() - 41) {
return true;
} else {
return false;
}
}
}
Regarding the code you did post, the problem seems to be that you never change the 'heading' which seems to control the direction of movement. There should be something like this: