布爾值總是返回false

Question

我已經在一個名爲findCar（）的方法中寫了一個循環，它通過鏈接列表汽車並檢查用戶輸入中輸入的Id是否與Car，Car實例Id從Car類的getId（）方法中收集。但它總是返回false，有人知道這是爲什麼嗎？您會看到對其他類的引用，例如客戶端和人員，但爲了簡單起見，我省略了它們，但如果具有該代碼將有助於達成答案，我將添加它。任何幫助是極大的讚賞

這裏是根類

import java.io.*; 

public class Root 
{ public Root() { 

    new CarManager(); 

} 

public static void main(String[] args) 
{ new Root(); } 


    private CarManager carManager; 
} 

這裏是類CarManager在那裏，循環被調用時，我已經標有//問題 區域！

import java.io.*; 
    import java.util.*; 

    public class CarManager implements Serializable 
    { private LinkedList<Car> cars = new LinkedList<Car>(); 
    private Clients clients = new Clients(); 

    public CarManager(){ 

    menu(); 

} 

    // !! Here is where the cars are initialized, the Id is the first number 
    public void setup() 
{ cars.add(new Car(1, "Ed", 3)); 
    cars.add(new Car(2, "Fred", 7)); 
    cars.add(new Car(3, "Freda", 5)); } 


public void menu() { 
    char choice; 
    while ((choice = readChoice()) !='x') { 
     switch(choice) { 
      case 'a': clients.makePerson(); break; 
      case 's': clients.showClients(); break; 
      case 'r':clients.removeClient(); break; 
      case 'b': findCar(); break; 
      default: showMenu(); // break; 
     } 

    } 
} 

private int nextInt() { 

    return In.nextInt(); 

} 

// !! Here is where the the loop is, it checks the entered Id value and 
// !! checks if it matches the Id value of the car objects.      

public void findCar() { 
    System.out.println("Please enter Id of car to be found"); 
    int searchid = In.nextInt(); 
    boolean carfound = false; 
    for (Car i: cars) 
    { 
     if (searchid == i.getId()) 
     { 
      carfound = true; 
      System.out.println("found car");} 
    } 

    if (carfound == false) 
     System.out.println("Did not find car"); 
} 

    private char readChoice() { 
    System.out.print("Your choice: "); 
    return In.nextChar(); 
} 

public void exit() { 

    System.exit(0); 

} 

} 

這裏是汽車類

import java.io.*; 
import java.util.*; 

    public class Car implements Serializable 
{ 
private int id; 
private String pilot; 
private int stops; 
private LinkedList<Person> passengers = new LinkedList<Person>(); 
private double rate = 10.00; 
public int scannableId = this.id; 
// 
public Car(int id, String pilot, int stops) 
{ this.id = id; 
    this.pilot = pilot; 
    this.stops = stops; } 


private void charge(int i) 
{ 
    //this is yet to be finished please ignore 
} 

private boolean stopAt(int i) 
{ for (Person person: passengers) 
     if (person.uses(i)) 
      return true; 
    return false; } 

private void showStop(int i) 
{ String s = " Stop " + i + "\n"; 
    String on = on(i); 
    if (!on.isEmpty()) 
     s += " On: " + on + "\n"; 
    System.out.print(s); } 

private String on(int i) 
{ String s = ""; 
    for (Person person: passengers) 
     if (person.getsOn(i)) 
      s += person.handle() + " "; 
    return s; } 
// !! Here is where the Id value is given from the instance of car 
public int getId() { 
    return this.id; 
} 


} 

這裏是用戶輸入處理

import java.util.*; 

public class In 
{ private static Scanner in = new Scanner(System.in); 

public static String nextLine() 
{ return in.nextLine(); } 

public static char nextChar() 
{ return in.nextLine().charAt(0); } 

public static int nextInt() 
{ int i = in.nextInt(); 
    in.nextLine(); 
    return i; } 

public static double nextDouble() 
{ double d = in.nextDouble(); 
    in.nextLine(); 
    return d; } 
} 

Answer 1

問題是你永遠不會調用CarManager.setUp()方法，這意味着鏈表總是空的，因此回報價值永遠是假的。