如标题中所述，如何从arrayList中删除属性，
我的方法是这样的：
public boolean removeBorrower(String libraryNumber)
我基本上必须检查此方法中的参数是否等于属性，如果是，则根据该删除借用者。
这是我的代码：
import java.util.*;
/**
* Write a description of class BorrowerList here.
*
* @author xxxxxx
* @version 08/11/2015
*/
public class BorrowerList
{
private ArrayList<Borrower> borrowers;
public BorrowerList()
{
borrowers = new ArrayList<Borrower>();
}
public void addBorrowers(Borrower borrower)
{
borrowers.add(borrower);
}
public void getAllBorrowers()
{
for(Borrower borrower : borrowers)
{
borrower.printBorrowerDetails();
}
}
public void getBorrower(int borrowerEntry)
{
if(borrowerEntry < 0)
{
System.out.println("Negative entry :" + borrowerEntry);
}
else if(borrowerEntry < getNumberOfBorrowers())
{
Borrower borrower = borrowers.get(borrowerEntry);
borrower.printBorrowerDetails();
}
else
{
System.out.println("No such entry :" + borrowerEntry);
}
}
public int getNumberOfBorrowers()
{
return borrowers.size();
}
public void removeBorrower(int borrowerEntry)
{
if(borrowerEntry < 0)
{
System.out.println("Negative entry :" + borrowerEntry);
}
else if(borrowerEntry < getNumberOfBorrowers())
{
borrowers.remove(borrowerEntry);
}
else
{
System.out.println("No such entry :" + borrowerEntry);
}
}
public boolean removeBorrower(String libraryNumber)
{
borrowers.remove(libraryNumber);
}
public int search(String libraryNumber)
{
int index = 0;
boolean found = false;
while(index < borrowers.size() && !found)
{
Borrower borrower = borrowers.get(index);
if(borrower.getLibraryNumber().equals(libraryNumber))
{
found = true;
}
else
{
index++;
}
}
if (index < borrowers.size())
{
return index;
}
else
{
return -1;
}
}
}
编辑：
以下是借款人类本身的代码
/**
* Write a description of class Borrower here.
*
* @author xxxxxx
* @version 08/11/2015
*/
public class Borrower
{
private String firstName;
private String lastName;
private String libraryNumber;
private int noOfBooks;
private Address address;
/**
* Constructor for objects of class Borrower.
* The number of books should be set to 1.
*
* @param firstName The Borrower's first name
* @param lastName The Borrower's last name
* @param lNumber The Borrower's library number
* @param street The Borrower's street
* @param town The Borrower's town
* @param postcode The Borrower's postcode
*/
public Borrower(String fName, String lName, String lNumber,
String street, String town, String postcode)
{
firstName = fName;
lastName = lName;
libraryNumber = lNumber;
noOfBooks = 1;
address = new Address(street, town, postcode);
}
/**
* Constructor for objects of class Borrower.
* The number of books on loan should should be set to
* the supplied vale.
*
* @param fName The Borrower's first name
* @param lName The Borrower's last name
* @param lNumber The Borrower's library number
* @param numberOfBooks The initial book borrow
* @param street The Borrower's street
* @param town The Borrower's town
* @param postcode The Borrower's postcode
*/
public Borrower(String fName, String lName, String lNumber, int numberOfBooks,
String street, String town, String postcode)
{
firstName = fName;
lastName = lName;
libraryNumber = lNumber;
noOfBooks = numberOfBooks;
address = new Address(street, town, postcode);
}
/**
* Get the Borrower's first name
*
* @return the Borrower's first name
*/
public String getFirstName()
{
return firstName;
}
/**
* Get the Borrower's last name
*
* @return the Borrower's last name
*/
public String getLastName()
{
return lastName;
}
/**
* Get the Borrower's library Number
*
* @return the Borrower's library number
*/
public String getLibraryNumber()
{
return libraryNumber;
}
/**
* Get the number of books on loan
*
* @return the number of books on loan
*/
public int getNoOfBooks()
{
return noOfBooks;
}
/**
* Print out the Borrower's details to the console window
*
*/
public void printBorrowerDetails()
{
System.out.println( firstName + " " + lastName
+ "\n" + address.getFullAddress()
+ "\nLibrary Number: " + libraryNumber
+ "\nNumber of loans: " + noOfBooks);
}
/**
* Increase the bumber of books on loan by 1
*
*/
public void borrowBook()
{
noOfBooks = noOfBooks + 1;
System.out.println("Books on loan: " + noOfBooks);
}
/**
* Increase the bumber of books on loan by a given number
*
* @param number of new loans to add to total
*/
public void borrowBooks(int number)
{
noOfBooks = noOfBooks + number;
System.out.println("Books on loan: " + noOfBooks);
}
/**
* Return a book
*
*/
public void returnBook ()
{
noOfBooks = noOfBooks - 1 ;
System.out.println("Books on loan: " + noOfBooks);
}
/**
* Return the Borrower's address
*
* @return the Borrower's address
*/
public String getAddress()
{
return address.getFullAddress();
}
/**
* Change the Borrower's address
*
* @param street the street
* @param town the town
* @param postcode the postcode
*/
public void setAddress(String street, String town, String postcode)
{
address.setFullAddress(street, town, postcode);
}
/**
* Print out Borrower's address
*/
public void printAddress()
{
address.printAddress();
}
} // end class
答案 0 :(得分：2)
根据JavaDoc：
public boolean remove（Object o）
从此列表中删除第一次出现的指定元素， 如果它存在。如果列表不包含该元素，则为 不变。更正式地，删除具有最低索引i的元素 这样（o == null？get（i）== null：o.equals（get（i）））（如果是这样的话） 元素存在）。如果此列表包含指定的，则返回true element（或等效地，如果此列表由于更改而更改） 呼叫）。
当且仅当您有一些等于该字符串的borrowers.remove(libraryNumber);对象时，这基本上意味着Borrower将起作用。除非您在equals课程中为Borrower方法添加了覆盖，否则它不太可能有效。因此，您有两种选择：
覆盖equals类中的hashcode()（以及良好做法，Borrower）方法，以使两个借用项目具有相同libraryNumber iterator 1}}。
第二个选项是使用Borrower浏览borrower中存储的remove项，并使用迭代器的Borrower方法删除具有相同属性值的对象。
作为旁注，虽然第一种方法可能对某些人来说更优雅，但必须谨慎，因为在您的特定情况下，libraryNumber对象可能不相同只是因为它们具有相同的document.getElementsByClassName("point")[a].style.top;
答案 1 :(得分：0)
public boolean removeBorrower(String libraryNumber)
{
boolean retVal = false;
if(borrowers.contains(libraryNumber))
{
retVal = borrowers.remove(libraryNumber);
}
return retVal;
}
也许这样的事情？我知道这是一个长期的做事方式，因为最简单的方法是
public boolean removeBorrower(String libraryNumber)
{
return borrowers.remove(libraryNumber);
}
但也许我不太明白你遇到的问题是什么？