Hi Zhoulei,
On Mar 31, 2012, at 11:12 , zhou lei wrote:
> I try to modify "ReadItemAsKey". Using SetValue to set the contacts, and i
> just guess that "read" mean read the local contacts and send them to server.
Exactly. The terms in the plugin are all meant towards the database.
> But with the struct fCB in the sample_dbplugin1.mm, just get a error named
> "EXC_BAD_ACCESS". And I use it like this "fCB->ui.SetValue( &fCB, aItemKey,
> "N_FIRST" ,VALTYPE_TEXT, "123131" , strlen("123131")); ", the fCB was set
> when init the "SamplePluginDB1".
I would really discourage using a mixture of ObjC and parts from the C++
examples. The ObjC wrapper was done exactly because dealing with the fCB and
it's members directly is difficult, and you need to do all the memory
management on your own.
EXC_BAD_ACCESS is a bus error which is hard to debug, especially as two
completely different memory management systems need to cooperate here (ObjC
refcounted world with C++/C traditional malloc/free world).
The ObjC wrapper classes however are really simple to use from the ObjC world.
I made a skeleton for the two read* methods to show how to easily access fields
from ObjC, without any messing with fCB, and with automatic conversion from
NSString (the SettingsKey also gives you convenience methods to access dates as
NSDate and integers).
- (TSyError)readNextItemAsKey:(SettingsKey *)aItemKey
itemIdP:(NSString **)aItemIdP parentIdP:(NSString **)aParentIdP
statusP:(sInt32 *)aStatusP
isFirst:(BOOL)aFirst
{
TSyError sta = LOCERR_OK;
[self debugOut:[NSString stringWithFormat:@"readNextItemAsKey: aFirst=%d",
aFirst]];
// read next item from DB
if (aFirst) {
// %%% reset iterator over dataset here
}
// get next item
BOOL found = NO;
do {
if (/* %%% no more data items */) {
*aStatusP = ReadNextItem_EOF;
break;
}
else {
found = YES;
// %%% get IDs of records from the database
// Note: data is not required at this point, however, if the database
is such
// that it always reads the data anyway when getting the IDs,
the data
// CAN be OPTIONALLY read here already (see below)
NSString *localID = /* item ID as string */ @"dummyID";
*aItemIdP = localID;
// %%% find out if it has modified since last time
if (/* %%% modified since last suspend */)
*aStatusP = ReadNextItem_Resumed; // changed since last resume (implies
changed since last sync also)
else if (/* %%% modified since last completed sync session */)
*aStatusP = ReadNextItem_Changed; // changed since last sync (but NOT
since last resume)
else
*aStatusP = ReadNextItem_Unchanged; // not changed, but caller wants to
see all records
// %%% optionally, you can ready actual item data from the DB here and
return it. If you don't deliver
// data here, the engine will later call readItemAsKey to get the data
// %%% just set some sample properties
// - simple strings
[aItemKey setStringValueByName:"N_FIRST" toValue:/* dummy first name */
@"Theodor"];
[aItemKey setStringValueByName:"N_LAST" toValue:/* dummy last name */
@"Tester"];
// - strings in an array
sInt32 telFieldID = [aItemKey valueIDByName:"TEL"];
for (int i=0; i<3; i++) {
[aItemKey setStringValueByID:telFieldID arrayIndex:i toValue:/* dummy
TEL */ @"12345 78 90"];
}
// %%% advance iterator to next item (such that next item will be
delivered on next call to reasNextItemAsKey
}
} while (!found);
// done
return sta;
}
- (TSyError)readItemAsKey:(SettingsKey *)aItemKey
itemID:(NSString *)aItemID parentID:(NSString *)aParentID
{
TSyError sta = LOCERR_OK;
[self debugOut:[NSString stringWithFormat:
@"readItemAsKey: itemID=%@ parentID=%@",
aItemID, aParentID
]];
// %%% read item identified by NSString in aItemID from DB
if (/* %%% found item with ID aItemID*/) {
// %%% just set some sample properties
// - simple strings
[aItemKey setStringValueByName:"N_FIRST" toValue:/* dummy first name */
@"Theodor"];
[aItemKey setStringValueByName:"N_LAST" toValue:/* dummy last name */
@"Tester"];
// - strings in an array
sInt32 telFieldID = [aItemKey valueIDByName:"TEL"];
for (int i=0; i<3; i++) {
[aItemKey setStringValueByID:telFieldID arrayIndex:i toValue:/* dummy TEL
*/ @"12345 78 90"];
}
}
else {
// item not found
sta = DB_NotFound;
}
// done
return sta;
}
Best Regards,
Lukas
PS: please make sure to Cc: your replies to the mailing list (Synthesis
) as well, and not only to me, so everyone on the
list can follow the conversation.
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