根据我的理解,这是一个内存问题,特别是因为我使用不同的计时器从多个地方多次调用该方法。
下面的代码抛出异常:
- (NSMutableArray*)getAllTraps
{
@synchronized(self)
{
self.fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Trap"];
NSError *error = nil;
NSArray *results = [self.managedObjectContext executeFetchRequest:self.fetchRequest error:&error];
if (!results)
{
NSLog(@"Error fetching traps: %@", error.localizedDescription);
NSLog(@"Reason: %@", error.localizedFailureReason);
NSLog(@"Suggestion: %@", error.localizedRecoverySuggestion);
abort();
}
if (error != nil)
{
// Handle error
NSLog(@"Error getting all traps");
}
else
{
// Handle success
NSLog(@"Success getting all traps");
}
NSMutableArray *arrayOfAllTraps = [[NSMutableArray alloc] init];
for (int i = 0; i < results.count; i++)
{
Trap *singleTrap = results[i];
NSMutableDictionary *singleDict = [[NSMutableDictionary alloc] init];
if (singleTrap.trapID.integerValue > 0)
{
singleDict[ID] = singleTrap.trapID;
singleDict[ALARMDISTANCE] = singleTrap.alarmDistance;
singleDict[ISACTIVE] = singleTrap.isActive;
singleDict[LAT] = singleTrap.lat;
singleDict[LON] = singleTrap.lon;
singleDict[POLYGONS] = singleTrap.polys;
// NSLog(@"Trap ID: %@, Trap Description: %@", singleTrap.trapID, singleTrap.trapDescription);
singleDict[DESCRIPTION] = singleTrap.trapDescription;
singleDict[ROADNUMBER] = singleTrap.roadNumber;
singleDict[TYPE] = singleTrap.type;
singleDict[DEGREES] = singleTrap.degrees;
singleDict[DIRECTION] = singleTrap.direction;
if (singleTrap.poly0 == nil)
{
singleDict[POLYGON_A] = @"";
}
else
{
singleDict[POLYGON_A] = singleTrap.poly0;
}
// Make sure not to set NULL value #1
if (singleTrap.poly1 == nil)
{
singleDict[POLYGON_B] = @"";
}
else
{
singleDict[POLYGON_B] = singleTrap.poly1;
}
if (singleTrap.poly2 == nil)
{
singleDict[POLYGON_C] = @"";
}
else
{
singleDict[POLYGON_C] = singleTrap.poly2;
}
// Make sure not to set NULL value #2
if (singleTrap.polygonAzimut1 == nil)
{
singleDict[POLYGON_A_AZIMUTH] = @"";
}
else
{
singleDict[POLYGON_A_AZIMUTH] = singleTrap.polygonAzimut1;
}
if (singleTrap.polygonAzimut2 == nil)
{
singleDict[POLYGON_B_AZIMUTH] = @"";
}
else
{
singleDict[POLYGON_B_AZIMUTH] = singleTrap.polygonAzimut2;
}
if (singleTrap.polygonAzimut3 == nil)
{
singleDict[POLYGON_C_AZIMUTH] = @"";
}
else
{
singleDict[POLYGON_C_AZIMUTH] = singleTrap.polygonAzimut3;
}
[arrayOfAllTraps addObject:singleDict];
}
}
return arrayOfAllTraps;
}
}
失败之后:
NSArray *results = [self.managedObjectContext executeFetchRequest:self.fetchRequest error:&error];
甚至没有进入'if'。
答案 0 :(得分:2)
试试这个,
NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
NSEntityDescription *entityDescription = [NSEntityDescription
entityForName:@"Trap" inManagedObjectContext:self.managedObjectContext];
[fetch setEntity:entityDescription];
NSError * error = nil;
NSArray *results = [self.managedObjectContext executeFetchRequest:fetch error:&error];