BlackBerry Persistent store

Question

Je développe une application dans laquelle je veux stocker de nombreuses entrées de données en utilisant le stockage persistant. le problème est que chaque fois qu'une nouvelle entrée est faite, elle remplace l'entrée existante. voici mon code s'il vous plaît aidez-moi.

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

En fait, il est sauve tout parfaitement, mais récupérer seul le dernier enregistrement:

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

Essayez cette option pour afficher tous les records:

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