我有大学的这个任务，花了好几个小时试图让各个部分在导师指南中工作（如果我可以将数组更改为public :(）会很容易。
Anway我有一个AccountList类，其中有一个名为accounts的数组，我需要使用这个方法
AccountList类
public int getNumberOfAccounts()
{
return accounts.size();
}
在我的基于文本的用户界面中将accounts.size作为字符串返回，这是我到目前为止所得到的但我无法解决如何将该accountList.getNumberOfAccounts转换为此类中的字符串以便我可以打印出来。
AccountTUI类
public void getNumberOfAccounts()
{
accountList.getNumberOfAccounts();
}
这是完整的代码集。
AccountTUI Full
import java.util.*;
/**
* Write a description of class AccountTUI here.
*
* @author (your name)
* @version (a version number or a date)
*/
public class AccountTUI
{
AccountList accountList = new AccountList();
Scanner myScanner = new Scanner(System.in);
public AccountTUI()
{
}
public void menu()
{
int command = -1;
while ( command != 0 )
{
displayMenu();
command = getCommand();
execute( command );
}
}
private void displayMenu()
{
System.out.println("\n Please Select An Option");
System.out.println("To quit enter 0");
System.out.println("To add an Account enter 1");
System.out.println("To remove an Account enter 2");
System.out.println("To get the number of Accounts enter 3");
System.out.println("To show a single Account enter 4");
System.out.println("To show all Accounts enter 5");
}
private int getCommand()
{
System.out.print ("Enter command: ");
int command = myScanner.nextInt();
myScanner.nextLine(); // handle eol
return command;
}
private void execute( int command)
{
if ( command == 0 )
quitCommand();
else
if ( command == 1)
addAccount();
else
if ( command == 2 )
removeAccount();
else
if ( command == 3)
getNumberOfAccounts();
else
if ( command == 4)
showAccount();
else
if ( command == 5)
showAllAccounts();
else {
unknownCommand(command);
}
}
public void addAccount()
{
Scanner keyboard = new Scanner(System.in);
System.out.print ("\n Enter First Name \n");
String firstname = keyboard.nextLine();
System.out.print ("Enter Second Name \n");
String secondname = keyboard.nextLine();
System.out.print ("Enter Account Number \n");
String accountnumber = keyboard.nextLine();
System.out.print ("Enter Street \n");
String street = keyboard.nextLine();
System.out.print ("Enter Town \n");
String town = keyboard.nextLine();
System.out.print ("Enter Postcode \n");
String postcode = keyboard.nextLine();
accountList.addAccount(new Account(firstname,secondname,accountnumber,
street,town,postcode));
}
public void getNumberOfAccounts()
{
accountList.getNumberOfAccounts();
}
public void quitCommand()
{
System.out.println("\n Application is closing");
System.exit(0);
}
public void removeAccount()
{
}
public void showAccount()
{
}
public void showAllAccounts()
{
System.out.print('\u000C');
accountList.getAllAccounts();
System.out.println("");
}
public void unknownCommand(int command)
{
if (command < 0 || command > 5) {
System.out.print('\u000C');
System.out.println("Unknown command.");
}
}
}
帐户列表已满
import java.util.*;
/**
* This is the AccountList class provide for students
* in Blackboard at the start of the homework
*
* @author (your name)
* @version (a version number or a date)
*/
public class AccountList
{
private ArrayList<Account> accounts;
/**
* Constructor for objects of class AccountList
*/
public AccountList()
{
accounts = new ArrayList<Account>();
}
public void addAccount(Account account)
{
accounts.add(account);
}
public int getNumberOfAccounts()
{
return accounts.size();
}
public boolean getAccount(String accountNumber)
{
int index = 0;
for (Account account : accounts)
{
if (accountNumber.equals(account.getAccountNumber()))
{
account.printAccountDetails();
return true;
}
else
{
index++;
}
}
return false;
}
public void getAccount(int accountEntry)
{
if (accountEntry < 0)
{
System.out.println("Negative entry: " + accountEntry);
}
else if (accountEntry < getNumberOfAccounts())
{
Account account = accounts.get(accountEntry);
account.printAccountDetails();
}
else
{
System.out.println("No such entry: " + accountEntry);
}
}
public void getAllAccounts()
{
for(Account account : accounts)
{
account.printAccountDetails();
System.out.println();
}
}
public void removeAccount(int accountEntry)
{
if(accountEntry < 0)
{
System.out.println("Negative entry :" + accountEntry);
}
else if(accountEntry < getNumberOfAccounts())
{
accounts.remove(accountEntry);
}
else
{
System.out.println("No such entry :" + accountEntry);
}
}
public boolean removeAccount(String accountNumber)
{
int index = 0;
for (Account account: accounts)
{
if (accountNumber.equals(account.getAccountNumber()))
{
accounts.remove(index);
return true;
}
index++;
}
return false;
}
public int search(String accountNumber)
{
int index = 0;
for (Account account : accounts)
{
if (accountNumber.equals(account.getAccountNumber()))
{
return index;
}
else
{
index++;
}
}
return -1;
}
}
答案 0 :(得分：1)
如果您想将int i转换为String，可以使用
String.valueOf(i);
所以你可以像这样修改你的方法：
public String getNumberOfAccounts()
{
return String.valueOf(accounts.size());
}
或者您可以将方法保持原样，并在希望将String.valueOf()表示放入用户界面时使用String。
但是你说你想在它上面使用println()。请注意，println()也会直接接受int，所以没有什么可以阻止你写的
System.out.println(getNumberOfAccounts());
即使getNumberOfAccounts()返回int。
另外，你应该注意到你没有使用数组（或者如果你是，你做错了）。数组上没有.size()方法;但是有一个ArrayList，所以我怀疑你正在使用它。数组的等价物是arr.length（没有()，因为它是一个字段而不是方法。）
答案 1 :(得分：0)
使用以下功能
public String getNumberOfAccounts()
{
return (""+accounts.size());
}