任务是用BB桌面管理器或以任何其他方式备份/恢复可持久对象。主要目的是在设备固件更新之间保持数据…
我:
public final class UserList implements Persistable {
//The persistable objects.
private Hashtable fData;
//Initialize the class with empty values.
public UserList() {
fData = new Hashtable();
}
//Initialize the class with the specified values.
public UserList(Hashtable p) {
fData = p;
}
public Hashtable getData() {
return fData;
}}
我也实现了SyncItem(如在一个例子中发现)
public final class UserListSync extends SyncItem {
private static UserList fList;
private static final int FIELDTAG_NAME = 1;
private static final int FIELDTAG_AGE = 2;
private static PersistentObject store;
static {
store = PersistentStore.getPersistentObject(0x3167239af4aa40fL);
}
public UserListSync() {
}
public String getSyncName() {
return "Sync Item Sample";
}
public String getSyncName(Locale locale) {
return null;
}
public int getSyncVersion() {
return 1;
}
public boolean getSyncData(DataBuffer db, int version) {
boolean retVal = true;
synchronized (store) {
if (store.getContents() != null) {
fList = (UserList)store.getContents();
}
}
try {
Enumeration e = fList.getData().keys();
while (e.hasMoreElements()) {
String key = (String) e.nextElement();
String value = (String) fList.getData().get(key);
//Write the name.
db.writeShort(key.length() + 1);
db.writeByte(FIELDTAG_NAME);
db.write(key.getBytes());
db.writeByte(0);
//Write the age.
db.writeShort(value.length() + 1);
db.writeByte(FIELDTAG_AGE);
db.write(value.getBytes());
db.writeByte(0);
}
} catch (Exception e) {
retVal = false;
}
return retVal;
}
//Interprets and stores the data sent from the Desktop Manager.
public boolean setSyncData(DataBuffer db, int version) {
int length;
Hashtable table = new Hashtable();
Vector keys = new Vector();
Vector values = new Vector();
boolean retVal = true;
try {
//Read until the end of the Databuffer.
while (db.available() > 0) {
//Read the length of the data.
length = db.readShort();
//Set the byte array to the length of the data.
byte[] bytes = new byte[length];
//Determine the type of data to be read (name or age).
switch (db.readByte()) {
case FIELDTAG_NAME:
db.readFully(bytes);
keys.addElement(new String(bytes).trim());
break;
case FIELDTAG_AGE:
db.readFully(bytes);
values.addElement(new String(bytes).trim());
break;
}
}
} catch (Exception e) {
retVal = false;
}
for (int i = 0; i < keys.size(); i++) {
table.put(keys.elementAt(i), values.elementAt(i));
}
try {
//Store the new data in the persistent store object.
fList = new UserList(table);
store.setContents(fList);
store.commit();
} catch (Exception e) {
retVal = false;
}
return retVal;
}}
入口点操作如下:
public class SyncItemSample extends UiApplication {
private static PersistentObject store;
private static UserList userList;
static {
store = PersistentStore.getPersistentObject(0x3167239af4aa40fL);
}
public static void main(String[] args) {
SyncItemSample app = new SyncItemSample();
app.enterEventDispatcher();
}
public SyncItemSample() {
UserListScreen userListScreen;
//Check to see if the store exists on the BlackBerry.
synchronized (store) {
if (store.getContents() == null) {
//Store does not exist, create it with default values
userList = new UserList();
store.setContents(userList);
store.commit();
} else {
//Store exists, retrieve data from store.
userList = (UserList)store.getContents();
}
}
//Create and push the UserListScreen.
userListScreen = new UserListScreen(userList);
pushScreen(userListScreen);
}}
下面是screen的实现:
public final class UserListScreen extends MainScreen {
Vector fLabels = new Vector();
Vector fValues = new Vector();
VerticalFieldManager leftColumn = new VerticalFieldManager();
VerticalFieldManager rightColumn = new VerticalFieldManager();
UserList fList;
public UserListScreen(UserList list) {
super();
fList = list;
//Create a horizontal field manager to hold the two vertical field
//managers to display the names and ages in two columns.
VerticalFieldManager inputManager = new VerticalFieldManager();
HorizontalFieldManager backGround = new HorizontalFieldManager();
//Array of fields to display the names and ages.
LabelField title = new LabelField("User List",
LabelField.ELLIPSIS | LabelField.USE_ALL_WIDTH);
setTitle(title);
final TextField fld1 = new TextField(TextField.NO_NEWLINE);
fld1.setLabel("input label");
inputManager.add(fld1);
final TextField fld2 = new TextField(TextField.NO_NEWLINE);
fld2.setLabel("input value");
inputManager.add(fld2);
final ButtonField fld3 = new ButtonField();
fld3.setChangeListener(new FieldChangeListener() {
public void fieldChanged(Field field, int context) {
fList.getData().put(fld1.getText().trim(), fld2.getText().trim());
refresh();
}
});
fld3.setLabel("add");
inputManager.add(fld3);
add(inputManager);
//Add the column titles and a blank field to create a space.
LabelField leftTitle = new LabelField("label ");
leftColumn.add(leftTitle);
LabelField rightTitle = new LabelField("value");
rightColumn.add(rightTitle);
refresh();
//Add the two vertical columns to the horizontal field manager.
backGround.add(leftColumn);
backGround.add(rightColumn);
//Add the horizontal field manager to the screen.
add(backGround);
}
private void refresh() {
leftColumn.deleteAll();
rightColumn.deleteAll();
fLabels.removeAllElements();
fValues.removeAllElements();
//Populate and add the name and age fields.
Enumeration e = fList.getData().keys();
while (e.hasMoreElements()) {
String key = (String) e.nextElement();
String value = (String) fList.getData().get(key);
final LabelField tmp1 = new LabelField(key);
final LabelField tmp2 = new LabelField(value);
leftColumn.add(tmp1);
rightColumn.add(tmp2);
fLabels.addElement(tmp1);
fValues.addElement(tmp2);
}
}
public boolean onClose() {
System.exit(0);
return true;
}}
正如你所看到的，它应该非常容易…
所以所有这些我运行应用程序，添加值到持久对象，它们被正确添加，在设备重置期间存储等等…当我运行桌面管理器并进行备份时，似乎UserList已备份，因为备份的大小随着向持久存储中添加新数据而增长。
但是当我在BB 9300上运行"擦设备"时(并且持久化存储的所有数据都按预期清除)，然后从刚刚制作的备份文件运行还原-应用程序中没有任何更新，持久化存储似乎是空的。
在一些例子中，我发现添加替代入口点"init"，但我不能像我的EclipsePlugin
所描述的那样调整一切你能告诉我如何在备份文件中存储数据，如何从备份中检索相同的数据并将其加载回应用程序，或者如何使用桌面管理器记录任何事件吗?
如果有人遇到了同样的问题，您可以在擦除设备之前尝试断开连接。这是奇怪的，但它帮助:)