我目前有以下代码，我想用 X 更新 2D 数组中的特定位置，然后重新打印板。我目前被困在需要将数组中的对象更新为 X 的地方，但我不断收到：
Type mismatch: cannot convert from String to Ship
我究竟做错了什么？我已经把所有的物体都放在了板上。
public void updateBoard(int row, int column, Ocean ocean){
//get ship array
Ship[][] sea = ocean.getShipArray();
//mark the x/y co-ordinate with X
sea[row][column] = "X"; // PROBLEM
// print the board
}
我已经包括了船级
public abstract class Ship {
// TODO add appropriate comments
@Getter
private int size;
private String type;
private String shortForm;
// TODO add appropriate comments
@Getter
@Setter(AccessLevel.PACKAGE)
private int bowRow;
@Getter
@Setter(AccessLevel.PACKAGE)
private int bowColumn;
@Getter
@Setter(AccessLevel.PACKAGE)
private boolean horizontal;
/**
* An array of boolean which indicates whether that part of the ship has
* been hit. This is initialised by the appropriate sub-class. Battleships
* use all 4 locations; cruisers use the first 3; destroyers 2; submarines
* 1; and "empty sea" 1.
*/
protected boolean[] hit;
/**
* clears the hit array indicating whether that part of the "Ship" has been
* hit
*/
protected Ship(int size, String type, String shortForm) {
this.size = size;
this.setType(type);
this.shortForm = shortForm;
hit = new boolean[size];
for (int i = 0; i < hit.length; i++)
hit[i] = false;
}
/**
* Checks that ship of this size will not overlap another ship, or touch
* another ship (vertically, horizontally, or diagonally) and that ship will
* not "stick out" beyond the array.
*
* @param row
* that will contain the bow
* @param column
* that will contain the bow
* @param horizontal = true if horizontal
* @param ocean
* @return true if it is okay to put a ship of this size with its bow in
* this location, with the given orientation.
*/
public boolean okToPlaceShipAt(int row, int column, boolean horizontal,
Ocean ocean) {
// Try to catch exception error if ship goes past board
try{
Ship ships[][] = ocean.getShipArray();
for (int i = 0; i < getSize(); i++){
if (!(ships[row][column] instanceof EmptySea)){
// System.out.println("Cant Print here + " + row + column + getSize());
return false;
}else{
if (horizontal) {
column++;
} else {
row++;
}
// System.out.print(ships[row][column]);
}
// System.out.println(" ");
}
return true;
}
catch(Exception err){
// System.out.println("OMG an error");
return false;
}
}
/**
* "places" the ship in the ocean, assigning values to the bowRow,
* bowColumn, and horizontal. Places a reference to the ship in the ships
* array in the Ocean object.
*
* @param row
* to contain the bow
* @param column
* to contain the bow
* @param horizontal
* @param ocean
*/
public void placeShipAt(int row, int column, boolean horizontal, Ocean ocean) {
this.setBowRow(row);
this.setBowColumn(column);
this.setHorizontal(horizontal);
Ship ships[][] = ocean.getShipArray();
for (int i = 0; i < getSize(); i++) {
// set position in array to contain the ship
ships[row][column] = this;
if (horizontal) {
column++;
} else {
row++;
}
}
}
private int getSize() {
// TODO Auto-generated method stub
return size;
}
private void setHorizontal(boolean horizontal2) {
// TODO Auto-generated method stub
horizontal = horizontal2;
}
private void setBowColumn(int column) {
// TODO Auto-generated method stub
bowColumn = column;
}
private void setBowRow(int row) {
// TODO Auto-generated method stub
bowRow = row;
}
/**
* If this ship has been hit, marks that part of the ship as "hit"
*
* @param row
* User's supplied row shot
* @param column
* User's supplied column shot
* @return true if ship is hit, false otherwise
*/
public boolean shootAt(int row, int column) {
if ((isHorizontal() && (row != getBowRow()))
|| (!isHorizontal() && (column != getBowColumn())))
return false; // it's not a hit
// it's a hit. Work out offset & set that position in hit array to true
hit[(row - getBowRow() + column - getBowColumn())] = true;
return true;
}
private int getBowRow() {
// TODO Auto-generated method stub
return bowRow;
}
private int getBowColumn() {
// TODO Auto-generated method stub
return bowColumn;
}
private boolean isHorizontal() {
// TODO Auto-generated method stub
return false;
}
/**
* checks whether this ship is sunk - using the hit array
*
* @return true if every part of the ship has been hit, false otherwise.
*/
public boolean isSunk() {
for (boolean b : hit)
if (!b)
return false;
return true;
}
/**
* @return a single character String to use in Ocean's print method
*/
@Override
public String toString() {
return shortForm;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String setHit(String hit){
return hit;
}
}
它有点长。下面是一个示例，如果是扩展 Ship 的船，即 Submarine 类。除了尺寸之外，所有其他的都完全相同。
/*
* A Battleship class which extends ship
* Four Submarines in the game Length 1
*/
package Battleships;
public class Submarine extends Ship {
private final static int SIZE = 1;
/**
* sets the length & clears the hit array
*/
public Submarine() {
super(SIZE, "Submarine", "S");
}
}