Java 充当指针的ArrayList内容
所以,我有代码为一个对象找到一个最接近0,0的空位。它陷入了一个无限循环,因为ArrayList就像一个指针列表Java 充当指针的ArrayList内容,java,arraylist,Java,Arraylist,所以,我有代码为一个对象找到一个最接近0,0的空位。它陷入了一个无限循环,因为ArrayList就像一个指针列表 private static voxel findEmptySpot(){ ArrayList<voxel> open = new ArrayList<voxel>(); ArrayList<voxel> closed = new ArrayList<voxel>(); String isla
private static voxel findEmptySpot(){
ArrayList<voxel> open = new ArrayList<voxel>();
ArrayList<voxel> closed = new ArrayList<voxel>();
String island = null;
open.add(new voxel(0,0));
do{
voxel pos = new voxel();
//Check for place closest to origin
int d = -1;
for(voxel test: closed){
SkyCraft.getInstance().getLogger().info("Closed: "+test.x+","+test.y);
}
for(voxel test: open){
int s = abs(test.x)+abs(test.y);
SkyCraft.getInstance().getLogger().info("Position "+test.x+", "+test.y+" distance "+s+" best "+d);
if(d==-1){
d = s;
pos.x = test.x;
pos.y = test.y;
}
if(s<d){
d = s;
pos.x = test.x;
pos.y = test.y;
}
}
SkyCraft.getInstance().getLogger().info("Closest found; testing.");
Island i = SkyCraft.db().getIsland(pos.x+";"+pos.y);
if(i.owner!=null){
if(i.owner.equals("")){
return pos;
}else{
voxel x1 = new voxel(pos.x+1, pos.y);
voxel x2 = new voxel(pos.x-1, pos.y);
voxel y1 = new voxel(pos.x, pos.y+1);
voxel y2 = new voxel(pos.x, pos.y-1);
if(!closed.contains(new voxel(pos.x+1, pos.y))){
if(!open.contains(new voxel(pos.x+1, pos.y))){
open.add(new voxel(pos.x+1, pos.y));
}
}
if(!closed.contains(new voxel(pos.x-1, pos.y))){
if(!open.contains(new voxel(pos.x-1, pos.y))){
open.add(new voxel(pos.x-1, pos.y));
}
}
if(!closed.contains(new voxel(pos.x, pos.y+1))){
if(!open.contains(new voxel(pos.x, pos.y+1))){
open.add(new voxel(pos.x, pos.y+1));
}
}
if(!closed.contains(new voxel(pos.x, pos.y-1))){
if(!open.contains(new voxel(pos.x, pos.y-1))){
open.add(new voxel(pos.x, pos.y-1));
}
}
open.remove(pos);
closed.add(pos);
}
}else{
return pos;
}
}while(true);
}
private静态体素findEmptySpot(){
ArrayList open=新建ArrayList();
ArrayList closed=新建ArrayList();
字符串孤岛=null;
添加(新体素(0,0));
做{
体素位置=新体素();
//检查离原点最近的地方
int d=-1;
用于(体素测试:关闭){
SkyCraft.getInstance().getLogger().info(“关闭:“+test.x+”,“+test.y”);
}
用于(体素测试:打开){
int s=abs(试验x)+abs(试验y);
SkyCraft.getInstance().getLogger().info(“位置”+test.x+,“+test.y+“距离”+s+“最佳”+d);
如果(d==-1){
d=s;
位置x=试验x;
位置y=试验y;
}
如果(s我刚刚使用“new”函数创建变量实例,ant然后将这些实例分配给ArrayList。感谢@William Price的帮助。Java集合都是通过引用创建的。因此如果我使用“new”要在每次向arraylist添加对象时引用新对象,列表中的每个引用都将具有唯一的对象,对吗?是的,每个单独的new
实例都将是一个单独的、唯一的引用,可以添加到列表中。您的代码还使用了list.contains()
这不一定与参考质量相同,这取决于被比较对象的类型以及它们的equals
方法的实现方式。另请参阅