BlackBerry Постоянный магазин

Question

Я разрабатываю приложение, в котором я хочу хранить много записей данных, используя постоянное хранилище. проблема возникает, когда новая запись делается заменой существующей записи. вот мой код, пожалуйста, помогите мне.

import net.rim.device.api.ui.*; 
import net.rim.device.api.ui.component.*; 
import net.rim.device.api.ui.container.*; 
import net.rim.device.api.system.*; 
import net.rim.device.api.util.*; 
import java.util.*; 
/*An application in which user enters the data. this data is displayed when user press the save button*/ 
public class Display extends UiApplication { 
/*declaring Strings to store the data of the user*/ 
String getFirstName; 
String getLastName; 
String getEmail; 
String getGender; 
String getStatus; 
/*declaring text fields for user input*/ 
private AutoTextEditField firstName; 

private AutoTextEditField lastName; 

private EmailAddressEditField email; 
/*declaring choice field for user input*/ 
private ObjectChoiceField gender; 
/*declaring check box field for user input*/ 
private CheckboxField status; 
//Declaring button fields 
private ButtonField save; 
private ButtonField close; 

/*declaring vector*/ 
private static Vector _data; 
/*declaring persistent object*/ 
private static PersistentObject store; 

/*creating an entry point*/ 
public static void main(String[] args) 
{ 
/*creating instance of the class */ 
Display app = new Display(); 
app.enterEventDispatcher(); 
} 

/*creating default constructor*/ 
public Display() 
{ 
    /*Creating an object of the main screen class to use its functionalities*/ 
    MainScreen mainScreen = new MainScreen(); 

    //setting title of the main screen 
    mainScreen.setTitle(new LabelField("Enter Your Data")); 

    //creating text fields for user input 
    firstName = new AutoTextEditField("First Name: ", ""); 
    lastName= new AutoTextEditField("Last Name: ", ""); 
    email= new EmailAddressEditField("Email:: ", ""); 

    //creating choice field for user input 
    String [] items = {"Male","Female"}; 
    gender= new ObjectChoiceField("Gender",items); 
    //creating Check box field 
    status = new CheckboxField("Active",true); 
    //creating Button fields and adding functionality using listeners 
    save = new ButtonField("Save",ButtonField.CONSUME_CLICK); 
    save.setChangeListener(new FieldChangeListener() 
    { 
    public void fieldChanged(Field field, int context) 
    { 
    save(); 
    } 
    }); 
    close = new ButtonField("Close",ButtonField.CONSUME_CLICK); 
    close.setChangeListener(new FieldChangeListener() 
    { 
    public void fieldChanged(Field field, int context) 
    { 
    onClose(); 
    } 
    }); 
    //adding the input fields to the main screen 
    mainScreen.add(firstName); 
    mainScreen.add(lastName); 
    mainScreen.add(email); 
    mainScreen.add(gender); 
    mainScreen.add(status); 
    //adding buttons to the main screen 
    mainScreen.add(close); 
    mainScreen.add(save); 

    //adding menu items 

    mainScreen.addMenuItem(saveItem); 
    mainScreen.addMenuItem(getItem); 
    //pushing the main screen 
    pushScreen(mainScreen); 
} 
//adding functionality to menu item "saveItem" 
private MenuItem saveItem = new MenuItem("Save", 110, 10) 
{ 
    public void run() 
    { 
    //Calling save method 
    save(); 
    } 
}; 
//adding functionality to menu item "saveItem" 
private MenuItem getItem = new MenuItem("Get", 110, 11) 
{ 
//running thread for this menu item 
public void run() 
{ 
    //synchronizing thread 
    synchronized (store) 
    { 
    //getting contents of the persistent object 
    _data = (Vector) store.getContents(); 
    //checking for empty object 
    if (!_data.isEmpty()) 
    { 
    //if not empty 
    //create a new object of Store Info class 
    StoreInfo info = (StoreInfo) 
    //returning last component of the vector 
    _data.lastElement(); 
    //storing information retrieved in strings 
    getFirstName = (info.getElement(StoreInfo.NAME)); 
    getLastName = (info.getElement(StoreInfo.LastNAME)); 
    getEmail = (info.getElement(StoreInfo.EMail)); 
    getGender = (info.getElement(StoreInfo.GenDer)); 
    getStatus = (info.getElement(StoreInfo.setStatus)); 

    //calling the show method 
    show(); 
    } 
    } 
} 
}; 
//coding for persistent store 
static { 
store = 
PersistentStore.getPersistentObject(0xdec6a67096f833cL); 
synchronized (store) { 
if (store.getContents() == null) { 
store.setContents(new Vector()); 
store.commit(); 
} 
} 
_data = new Vector(); 
_data = (Vector) store.getContents(); 

} 
//new class store info implementing persistable 
private static final class StoreInfo implements Persistable 
{ 
//declaring variables 
private Vector _elements; 
public static final int NAME = 0; 
public static final int LastNAME = 1; 
public static final int EMail= 2; 
public static final int GenDer = 3; 
public static final int setStatus = 4; 

public StoreInfo() 
{ 
    _elements = new Vector(5); 
    for (int i = 0; i < _elements.capacity(); ++i) 
    { 
    _elements.addElement(new String("")); 
    } 
} 

public String getElement(int id) 
{ 
    return (String) _elements.elementAt(id); 
} 
public void setElement(int id, String value) 
{ 
    _elements.setElementAt(value, id); 
} 
} 
//details for show method 
public void show() 
{ 
Dialog.alert("Name is "+getFirstName+" "+getLastName+"\nGender is "+getGender+"\nE-mail: "+getEmail+"\nStatus is "+getStatus); 
} 
//creating save method 
public void save() 
{ 
//creating an object of inner class StoreInfo 
StoreInfo info = new StoreInfo(); 
//getting the test entered in the input fields 
info.setElement(StoreInfo.NAME, firstName.getText()); 
info.setElement(StoreInfo.LastNAME,lastName.getText()); 
info.setElement(StoreInfo.EMail, email.getText()); 
info.setElement(StoreInfo.GenDer,gender.toString()); 
if(status.getChecked()) 
    info.setElement(StoreInfo.setStatus, "Active"); 
else 
    info.setElement(StoreInfo.setStatus, "In Active"); 
//adding the object to the end of the vector 
_data.addElement(info); 
//synchronizing the thread 
synchronized (store) 
{ 

    store.setContents(_data); 
    store.commit(); 
} 
//resetting the input fields 

Dialog.inform("Success!"); 
firstName.setText(null); 
lastName.setText(null); 
email.setText(""); 
gender.setSelectedIndex("Male"); 
status.setChecked(true); 
} 
//overriding onClose method 
public boolean onClose() 
{ 
System.exit(0); 
return true; 
} 
} 

Answer 1

На самом деле это сохраняет все отлично, но извлечение только последняя запись:

StoreInfo info = (StoreInfo)_data.lastElement(); 

Попробуйте это, чтобы показать все записи:

for (int i = 0; i < _data.size(); i++) { 
StoreInfo info = (StoreInfo)_data.elementAt(i); 
... 
show(); 
}