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我已經看過關於此主題的其他答案，但沒有找到任何幫助。下面是我有類：非靜態方法不能從靜態上下文中引用，但什麼都不是靜態的
import java.util.ArrayList;
/**
* Manage the stock in a business.
* The stock is described by zero or more Products.
*
* @author
* @version
*/
public class StockManager
{
// A list of the products.
private ArrayList<Product> stock;
/**
* Initialise the stock manager.
*/
public StockManager()
{
stock = new ArrayList<Product>();
}
/**
* Add a product to the list.
* @param item The item to be added.
*/
public void addProduct(Product item)
{
for(Product product: stock)
{
if(Product.getID() == item)
{
System.out.println("Please add an item with a different id");
}
else
{
stock.add(item);
}
}
}
/**
* Receive a delivery of a particular product.
* Increase the quantity of the product by the given amount.
* @param id The ID of the product.
* @param amount The amount to increase the quantity by.
*/
public void delivery(int id, int amount)
{
for(Product product : stock)
{
if(findProduct(id) != null)
{
increaseQuantity(amount);
}
}
}
/**
* Try to find a product in the stock with the given id.
* @return The identified product, or null if there is none
* with a matching ID.
*/
public Product findProduct(int id)
{
for(Product product : stock)
{
if(id == getID())
{
return getName();
}
else
{
return null;
}
}
}
/**
* Locate a product with the given ID, and return how
* many of this item are in stock. If the ID does not
* match any product, return zero.
* @param id The ID of the product.
* @return The quantity of the given product in stock.
*/
public int numberInStock(int id)
{
for(Product product : stock)
{
if(id == getID())
{
getQuantity();
}
else
{
return 0;
}
}
}
/**
* Print details of all the products.
*/
public void printProductDetails()
{
for(Product product: stock)
{
toString();
}
}
/**
* This method prints the deatils
* of products under a certain quantity
* @param the amount you want to check under
*/
public void lowStockCheck(int amount)
{
for(Product product : stock)
{
if(getQuantity() < amount)
{
printProductDetails();
}
}
}
/**
* Find a product via it's name
* rather than ID
* @param Name of product
*/
public Product findProductName(String name)
{
for(Product product : stock)
{
if(name.equals(getName()))
{
return getName();
}
else
{
return null;
}
}
}
，這裏是產品類：
/**
* Model some details of a product sold by a company.
*
* @author David J. Barnes and Michael Kölling.
* @version 2011.07.31
*/
public class Product
{
// An identifying number for this product.
private int id;
// The name of this product.
private String name;
// The quantity of this product in stock.
private int quantity;
/**
* Constructor for objects of class Product.
* The initial stock quantity is zero.
* @param id The product's identifying number.
* @param name The product's name.
*/
public Product(int id, String name)
{
this.id = id;
this.name = name;
quantity = 0;
}
/**
* @return The product's id.
*/
public int getID()
{
return id;
}
/**
* @return The product's name.
*/
public String getName()
{
return name;
}
/**
* @return The quantity in stock.
*/
public int getQuantity()
{
return quantity;
}
/**
* @return The id, name and quantity in stock.
*/
public String toString()
{
return id + ": " +
name +
" stock level: " + quantity;
}
/**
* Restock with the given amount of this product.
* The current quantity is incremented by the given amount.
* @param amount The number of new items added to the stock.
* This must be greater than zero.
*/
public void increaseQuantity(int amount)
{
if(amount > 0) {
quantity += amount;
}
else {
System.out.println("Attempt to restock " +
name +
" with a non-positive amount: " +
amount);
}
}
/**
* Sell one of these products.
* An error is reported if there appears to be no stock.
*/
public void sellOne()
{
if(quantity > 0) {
quantity--;
}
else {
System.out.println(
"Attempt to sell an out of stock item: " + name);
}
}
我得到的錯誤是在StockManager類的addProduct命令功能。這段代碼專門
/**
* Add a product to the list.
* @param item The item to be added.
*/
public void addProduct(Product item)
{
for(Product product: stock)
{
if(Product.getID() == item)
{
System.out.println("Please add an item with a different id");
}
else
{
stock.add(item);
}
}
}
錯誤說「非靜態方法的getID（）不能從靜態上下文中引用」這些方法都不是靜態的，因爲在這個時間點上，我們有沒有必要爲他們。我在這裏錯過了什麼？
您的意思是'product.getID（）'，帶有_lowercase_'''嗎？ – rgettman
歡迎來到Stack Overflow。請始終嘗試將問題減少到[mcve] - 這裏包含了超過250行的代碼，用於可能在大約15次顯示的內容。 –
哦，我的上帝..我一直在試圖解決這個問題像現在三天。非常感謝！ – Blaza