Java：要在一个充满自定义对象的ArrayList中使用包含，我应该覆盖等于或实现可比/比较器吗？
2022-09-02 09:42:40
我有一个充满这些的数组列表：
class TransitionState {
Position positionA;
Position positionB;
int counter;
public boolean equals (Object o){
if (o instanceof TransitionState){
TransitionState transitionState= (TransitionState)o;
if ((this.positionA.equals(transitionState.positionA))
&&(this.positionB.equals(transitionState.positionB)))
{
return true;
}
}
return false;
}
@Override
public String toString() {
String output = "Position A " + positionA.i+ " "+ positionA.j + " "+ positionA.orientation + " "+
"Position B " + positionB.i + " "+ positionB.j + " "+ positionB.orientation;
return output;
}
}
class Position {
int i;
int j;
char orientation;
Position() {
}
void setIJ(int i, int j){
this.i=i;
this.j=j;
}
void setOrientation(char c){
orientation = c;
}
public boolean equals(Object o){
if(o instanceof Position){
Position p = (Position)o;
if((p.i==this.i)&&(p.j==this.j)&&(p.orientation==this.orientation))
{
return true;
}
else return false;
}
return false;
}
} //end class Position
我用这个查询它：
if(!transitionStatesArray.contains(newTransitionState)){ //if the transition state is new add and enqueue new robot positions
transitionStatesArray.add(newTransitionState); //marks as visited
我在 里面发现了重复的元素，为什么会这样？transitionStatesArray
我使用这些i，j和方向值来填充矩阵中的唯一值，但在这里我有一个副本：
S . N
* * *
. D D
E . O
* * *
. D D
N . S
* * *
. D D
S . N
* * *
. D D
