Persistent data storage
Create a persistent data store
Each
PersistentObject
has a unique long key.
1.
Import the following classes:
•
net.rim.device.api.system.PersistentObject
•
net.rim.device.api.system.PersistentStore
•
java.lang.String
•
net.rim.device.api.ui.component.Dialog
2.
To create a unique long key, in the BlackBerry® Integrated Development Environment, type a string value.
com.rim.samples.docs.userinfo
3.
Right-click the string and click
Convert ‘com.rim.samples.docs.userinfo’ to long
.
4.
Include a comment in your code to indicate the string that you used to generate the unique long key.
5.
To create a persistent data store, create a single static
PersistentObject
and invoke
PersistentStore.getPersistentObject
, using the unique long key as a parameter.
static PersistentObject store;
static {
store = PersistentStore.getPersistentObject( 0xa1a569278238dad2L );
}
Store persistent data
1.
Import the following classes:
•
net.rim.device.api.system.PersistentStore
•
net.rim.device.api.system.PersistentObject
2.
Invoke
setContents()
on a
PersistentObject
. This method replaces existing content with the new content.
3.
To save the new content to the persistent store, invoke
commit()
.
String[] userinfo = {username, password};
synchronized(store) {
store.setContents(userinfo);
store.commit();
}
4.
To use a batch transaction to commit objects to the persistent store, invoke
PersistentStore.getSynchObject()
. This method retrieves the persistent store monitor that locks the
object.
Development Guide
Persistent data storage
46
