내 for 루프가 올바른 속성을 가리키고 있지 않습니다.

Question

for 루프가 어떤 메뉴를 찾았는지 찾으면 가격을 가리키고 싶습니다. 일단 내가 계산자가 선택하는 메뉴를 찾으면 getPrice() 메서드를 사용하고 JtTextField (totalText)로 설정된 문자열과 동일하게 설정합니다.

문제는 단지 항상 0.0을 표시하고 내가 선택한 것의 가격이 결코 없다는 것입니다. 어떻게해야합니까? 여기

는 여기에 메뉴 프레임

// NamesFrame.java 
// 
// Informatics 45 Spring 2010 
// Code Example: GridBagLayouts, JLists, and ListModels 
// Version 2 
// 
// This version of NamesFrame employs model/view separation. In order to 
// do it, it stores a NameCollection (our model) instead of a DefaultListModel, 
// then implements its own custom ListModel that knows how to handle event 
// notifications from NameCollection and turn them into events that JLists 
// can handle. 

package inf45.spring2010.examples.gui3; 

import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 


public class MenuFrame extends JFrame 
{ 
    private MenuCollection menu; 
    private JList menuList; 
    private JTextField newNameField; 
    private JList orderList; 
    private JButton orderButton, cancelButton; 
    private JTextField totalText; 
    private JTextField inputText; 
    DefaultListModel dm = new DefaultListModel(); 
    public menuItem[] mi; 
    private double getPrice; 

    menuItem [] menuArray = new menuItem [13]; 

    public MenuFrame() 
    { 


     menu = new MenuCollection(); 

     setTitle("Senor Club"); 
     setSize(1000, 1000); 
     setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE); 

     menuArray[0] = new menuItem("Cheese Enchilada", 2.95, true); 
     menuArray[1]= new menuItem ("Chicken Enchilada", 3.59, true); 
     menuArray[2]= new menuItem ("Beef Taco", 1.69, true); 
     menuArray [3]= new menuItem ("Chicken Taco", 1.89, true); 
     menuArray [4] = new menuItem ("Fish Taco", 2.39, true); 
     menuArray [5] = new menuItem ("Bean and Cheese Burrito", 3.19, true); 
     menuArray [6] = new menuItem ("Chicken Burrito", 5.49, true); 
     menuArray [7] = new menuItem ("Steak Burrito", 6.49, true); 
     menuArray [8] = new menuItem ("Carnitas Burrito", 6.79, true); 
     menuArray [9] = new menuItem ("Chips and Salsa", .99, true); 
     menuArray [10] = new menuItem ("Guacamole", 2.49, false); 
     menuArray [11] = new menuItem ("Small Drink", 1.45, false); 
     menuArray [12] = new menuItem ("Large Drink", 1.95, false); 

     mi = menuArray; 

     buildUI(); 
    } 


    // All of the layout code has stayed the same. The only difference in 
    // this method is where we create the list model; instead of creating a 
    // DefaultListModel (which stores its own data), we create a NamesListModel, 
    // our own custom list model that knows how to interact with the 
    // NameCollection. 
    private void buildUI() 
    { 

     GridBagLayout layout = new GridBagLayout(); 
     getContentPane().setLayout(layout); 

     NamesListModel listModel = new NamesListModel(menu); 
     menuList = new JList(menuArray); 

     menuList.addMouseListener(new MouseAdapter() 
     { 
      @Override 
      public void mousePressed(MouseEvent e) 
      { 

       Object selected = menuList.getSelectedValue(); 
       System.out.println("menuList.addMouseListener.mousePressed selected=" + selected); 
       DefaultListModel dm = (DefaultListModel) orderList.getModel(); 
       dm.add(orderList.getModel().getSize(), selected); 

       for (int i = 0; i < menuArray.length; i++){ 
        if (selected.equals(mi[i].getItemName())) { 
         getPrice =  mi[i].getItemPrice(); 

      } 

     } 
      String getDisplayPrice = getPrice + ""; 
      totalText.setText(getDisplayPrice); 

       } 
     }); 

     orderList = new JList(dm); 

     JScrollPane orderListScrollPane = new JScrollPane(orderList); 

     getContentPane().add(orderListScrollPane); 
     layout.setConstraints(
      orderListScrollPane, 
      new GridBagConstraints(
       1, 1, 2, 1, 1.0, 1.0, 
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(5, 10, 5, 10), 0, 0)); 


     JScrollPane menuListScrollPane = new JScrollPane(menuList); 
     getContentPane().add(menuListScrollPane); 
     layout.setConstraints(
      menuListScrollPane, 
      new GridBagConstraints(
       0, 1, 2, 1, 1.0, 1.0, 
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(5, 10, 5, 10), 0, 0)); 

     JScrollPane recieptListScrollPane = new JScrollPane(); 
     getContentPane().add(recieptListScrollPane); 
     layout.setConstraints(
      recieptListScrollPane, 
      new GridBagConstraints(
       3, 1, 2, 1, 1.0, 1.0, 
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(5, 10, 5, 10), 0, 0)); 

     totalText = new JTextField(); 
     Font font = new Font("Verdana", Font.BOLD, 30); 
     totalText.setFont(font); 
     totalText.setForeground(Color.RED); 
     getContentPane().add(totalText); 
     layout.setConstraints(
       totalText, 
       new GridBagConstraints(0, 3, 2, 1, 1.0, 1.0, 
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(5, 5, 5, 10), 0, 0)); 

     inputText = new JTextField(); 
     Font inputFont = new Font("Verdana", Font.BOLD, 30); 
     totalText.setFont(inputFont); 
     totalText.setForeground(Color.RED); 
     getContentPane().add(inputText); 
     layout.setConstraints(
      inputText, 
      new GridBagConstraints(
       1, 3, 2, 1, 1.0, 1.0, 
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(5, 10, 5, 10), 0, 0)); 

     JButton payLabel = new JButton("Pay"); 
     getContentPane().add(payLabel); 
     layout.setConstraints(
      payLabel, 
      new GridBagConstraints(
       3, 3, 2, 1, 1.0, 1.0, 
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(5, 10, 5, 10), 0, 0)); 

     orderButton = new JButton("Order"); 
     new ActionListener() 
     { 
      public void actionPerformed(ActionEvent e) 
      { 



      } 
     }; 
     getContentPane().add(orderButton); 
     layout.setConstraints(
      orderButton, 
      new GridBagConstraints(
       0, 2, 1, 1, 0.5, 0.0, 
       GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL, 
       new Insets(5, 10, 5, 5), 0, 0)); 

     cancelButton = new JButton("Cancel"); 
     //addButton.addActionListener(
      new ActionListener() 
      { 
       public void actionPerformed(ActionEvent e) 
       { 
        cancelPressed(); 

       } 
      }; 
     getContentPane().add(cancelButton); 
     layout.setConstraints(
      cancelButton, 
      new GridBagConstraints(
       1, 2, 1, 1, 0.0, 0.0, 
       GridBagConstraints.EAST, GridBagConstraints.NONE, 
       new Insets(5, 5, 5, 10), 0, 0)); 
    } 

    // In this method, we add the new name to the NameCollection instead of 
    // adding it directly to the list model. This sets off a chain of events: 
    // 
    // * NameCollection notifies its listener, the NamesListModel, that a name 
    // has been added. 
    // * NamesListModel notifies its listener, the JList, that an "interval" 
    // (a subsequence of the elements) has changed. 
    // * JList redraws the affected elements (if they're visible). 
    // 
    private void addName() 
    { 
     String newName = newNameField.getText().trim(); 

     if (newName.isEmpty()) 
     { 
      JOptionPane.showMessageDialog(
       this, "No name was specified. Please enter a name.", "No Name Specified", 
       JOptionPane.ERROR_MESSAGE); 
     } 
     else 
     { 
      menu.add(newName); 
      newNameField.setText(""); 
     } 
    } 


    // In this method, we remove the name from the NameCollection instead of the 
    // list model, which sets off the same chain of events that addName() does. 


    // This is a custom list model. It extends AbstractListModel, which 
    // provides a basic implementation of some of the ListModel functionality, 
    // while leaving the important parts of it (namely, how to figure out how 
    // large the collection is and how to get an element from the collection) 
    // unimplemented; this class implements those two elements, which are 
    // called getSize() and getElementAt(). 
    // 
    // Our list model also implements the NameCollectionChangedListener 
    // interface, so that it can receive change events from the NameCollection. 
    // It's legal in Java for a class to extend another class and implement 
    // an interface. (In fact, it's legal for a class to extend a class and 
    // implement multiple interfaces, if you're so inclined.) It's not legal, 
    // however, for a class to extend multiple other classes. 
    private class NamesListModel 
    extends AbstractListModel 
    implements NameCollectionChangedListener 
    { 
     // The list model will operate on the collection, so we'll need to 
     // store a reference to the collection inside the list model. 
     private MenuCollection collection; 


     // When we create the list model, we need to store the collection 
     // and register the list model as a listener on the collection, 
     // so that whenever the collection is changed, the list model 
     // will be notified. 
     public NamesListModel(MenuCollection collection) 
     { 
      this.collection = collection; 
      collection.addNameCollectionChangedListener(this); 
     } 


     // This is the method that will be called whenever the NameCollection 
     // has a name added to it. What it does is fire an "interval added" 
     // event, which is how it tells its JList that some subsequence of 
     // elements has changed. The three parameters are (1) who sent the 
     // event, (2) where the sequence of changed elements begins, and 
     // (3) where the sequence of changed elements ends. In our case, the 
     // sequence of changed elements is just the one element, so we say 
     // "index" in both places; why the method specifies the beginning and 
     // end separately is so that you can cheaply add, say, 10 elements 
     // without having to fire 10 events. 
     public void nameAdded(int index) 
     { 
      fireIntervalAdded(this, index, index); 
     } 


     // This is the method that will be called whenever the NameCollection 
     // has a name removed from it. It does something similar to nameAdded(), 
     // except that it notifies its JList about the removal of an element, 
     // appropriately, instead of the addition of an element. 
     public void nameRemoved(int index) 
     { 
      fireIntervalRemoved(this, index, index); 
     } 


     // Whenever the JList asks the list model how many elements there are 
     // in the list, the list model will just ask the collection "How many 
     // names have you got?" 
     public int getSize() 
     { 
      return collection.getSize(); 
     } 


     // Whenever the JList asks the list model what element is at a 
     // particular index, the list model will just ask the collection 
     // "What name is at this index?" 
     public Object getElementAt(int index) 
     { 
      return collection.get(index); 
     } 
    } 


    private void cancelPressed() 
    { 
     dispose(); 
    } 
    public void addMenu() 
    { 

    } 
} 

입니다 I 메뉴에 대해 생성 된 클래스

package inf45.spring2010.examples.gui3; 

import java.text.DecimalFormat; 

public class menuItem { 

    private String name; 

    private double price; 

    private boolean taxable; 

    public int index; 

    //menuArray = new string [10]; 

    public menuItem(String name, double price, boolean taxable) 

    { 

    this.name = name; 

    this.price = price; 

    this.taxable = taxable; 

    } 

    public String getItemName() 

    { 

    return name; 

    } 

    public double getItemPrice() 

    { 

    double d = price; 

      DecimalFormat df = new DecimalFormat("#.##"); 

    return Double.valueOf(df.format(d)); 

    } 

    public String toString() 

    { 

    String s = ""; 

    s += name + ": $" + getItemPrice(); 

    return s; 

    } 

    public boolean isTaxable() 

    { 

    return taxable; 

    } 

    } 

Answer 1

귀하의 비교가 잘못입니다 :

selected.equals(mi[i].getItemName())이 menuItem 및 String 사이에 비교합니다.

당신은 배열

menuItem selected = (menuItem)menuList.getSelectedValue(); 
... 
for (int i = 0; i < menuArray.length; i++){ 
    if (selected.equals(mi[i])) { 
     getPrice =  mi[i].getItemPrice(); 

또는 더 나은에서는 menuItem에 menulist 요소에서 반환 된 객체를 캐스팅하고 비교해야 -

가

int selected = menuList.getSelectedIndex(); 
getPrice = mi[selected].getItemPrice();