我有一个NSArray
拥有一些NSDictionary
,每次我保存一个NSDictionary
对象并将其添加到NSArray
,我发送给它添加/更新功能。
我知道我读取的数据是正确的,当我以前添加没有更新功能的数据时,所有数据都插入CoreData
,但我想添加更新函数来验证我放的数据。
现在,该函数添加第一个对象,然后一遍又一遍地进入'更新'。
怎么了?
我的代码:
-(void)updateOrAddTrap:(NSMutableDictionary*)trapObject
{
NSInteger trapID = [trapObject[@"id"] integerValue];
Trap *trapEntity = nil;
NSError *error = nil;
Boolean success = true;
self.fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Trap"];
self.predicate = [NSPredicate predicateWithFormat:@"trapID == %d", trapID];
[self.fetchRequest setPredicate:self.predicate];
NSArray *results = [self.managedObjectContext executeFetchRequest:self.fetchRequest error:&error];
if (results == nil)
{
// Handle error
NSLog(@"HANDLE ERROR");
success = false;
}
else if ([results count] == 0)
{
// Nothing to update, add new trap
NSLog(@"NOTHING TO UPDATE | ADD NEW");
// Create a new record (row)
trapEntity = [NSEntityDescription insertNewObjectForEntityForName:@"Trap" inManagedObjectContext:self.managedObjectContext];
}
else
{
NSLog(@"UPDATE EXISTING OBJECT");
trapEntity = results[0]; // There should be only one object for the ID.
}
if (trapEntity != nil)
{
// Set properties for new or existing object ...
// Int
int alarmDistance = [[trapObject objectForKey:ALARMDISTANCE] intValue];
int type = [[trapObject objectForKey:TYPE] intValue];
int roadNumber = [[trapObject objectForKey:ROADNUMBER] intValue];
int trap_id = [[trapObject objectForKey:ID] intValue];
int polys = [[trapObject objectForKey:POLYGONS] intValue];
int degrees = [[trapObject objectForKey:DEGREES] intValue];
[trapEntity setAlarmDistance:[NSNumber numberWithInt:alarmDistance]];
[trapEntity setType:[NSNumber numberWithInt:type]];
[trapEntity setRoadNumber:[NSNumber numberWithInt:roadNumber]];
[trapEntity setTrapID:[NSNumber numberWithInt:trap_id]];
[trapEntity setPolys:[NSNumber numberWithInt:polys]];
[trapEntity setDegrees:[NSNumber numberWithInt:degrees]];
// Boolean
BOOL isActive = [[trapObject objectForKey:ISACTIVE] integerValue] == 1 ? YES : NO;
[trapEntity setIsActive:[NSNumber numberWithBool:isActive]];
// Float
float lat = [[trapObject objectForKey:LAT] floatValue];
float lon = [[trapObject objectForKey:LON] floatValue];
[trapEntity setLat:[NSNumber numberWithFloat:lat]];
[trapEntity setLon:[NSNumber numberWithFloat:lon]];
// NSString
[trapEntity setDirection:[trapObject objectForKey:DIRECTION]];
[trapEntity setTrapDescription:[trapObject objectForKey:DESCRIPTION]];
[trapEntity setPoly0:[trapObject objectForKey:POLYGON_A]];
[trapEntity setPoly1:[trapObject objectForKey:POLYGON_B]];
[trapEntity setPoly2:[trapObject objectForKey:POLYGON_C]];
[trapEntity setPolygonAzimut1:[trapObject objectForKey:POLYGON_A_AZIMUTH]];
[trapEntity setPolygonAzimut2:[trapObject objectForKey:POLYGON_B_AZIMUTH]];
[trapEntity setPolygonAzimut3:[trapObject objectForKey:POLYGON_C_AZIMUTH]];
// etc. for all properties ...
if (![self.managedObjectContext save:&error])
{
NSLog(@"HANDLE ERROR WHEN SAVING THE OBJECT");
success = false;
}
}
}
我很高兴知道如何正确更新,因为我现在也错过了此功能。
修改 感谢马丁,这段代码就像一个魅力。
答案 0 :(得分:4)
我不确定这是否是您的问题的原因,但是您检查错误 条件或空结果是错误的。它应该是
BOOL success = true;
Trap *trap = nil;
NSArray *results = [self.managedObjectContext executeFetchRequest:self.fetchRequest error:&error];
if (results == nil) {
NSLog(@"HANDLE ERROR");
success = false;
} else if ([results count] == 0) {
NSLog(@"NOTHING TO UPDATE | ADD NEW");
trap = [NSEntityDescription insertNewObjectForEntityForName:@"Trap" inManagedObjectContext:self.managedObjectContext];
} else {
NSLog(@"UPDATE EXISTING OBJECT");
trap = result[0]; // There should be only one object for the ID.
}
if (trap != nil) {
// Set properties for new or existing object ...
[trap setTrapID:[NSNumber numberWithInt:trap_id]];
// etc. for all properties ...
if (![self.managedObjectContext save:&error]) {
NSLog(@"HANDLE ERROR WHEN SAVING THE OBJECT");
success = false;
}
}
executeFetchRequest
返回
nil
如果发生错误,