NSManagedObjectContext只能运行几次，然后停止工作 [英] NSManagedObjectContext work well only a few times, then it stops working
本文介绍了NSManagedObjectContext只能运行几次，然后停止工作的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
在我尝试问了两次并解释了自己之后，我做了一个挖掘，我想我现在可以更好地解释我的问题了：
1）我正在使用核心数据保存到 NSManagedObjects ： CoreDataTrap & CoreDataAllTraps 。
第一次，我解析一个较大的xml，然后转换为数组，然后将详细信息添加到 CoreDataAllTraps ，此操作进展顺利，因为我知道
2）然后，为了测试，我正在获取所有记录并记录它们的总数。
这些功能为我提供了正确的记录数。
3）然后只初始化一些变量。
4）然后初始化我的四叉树。
错误：fetchedObjects没有记录。
5）然后，使用核心数据的所有其他功能当然都会返回错误，因为没有数据。
相关（编号）代码：
1：
---
-（无效） addOrUpdateTrap :(陷阱*）trapObject
{
NSManagedObjectContext * context = generateManagedObjectContext（）;
int trapID = trapObject.getTrapID;
CoreDataAllTraps * trapEntity = nil;
NSError *错误=无;
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] initWithEntityName：kCORE_DATA_ALL_TRAPS_ENTITY];
NSPredicate * predicate = [NSPredicate predicateWithFormat：@ trapID ==％d，trapID];
[fetchRequest setPredicate：predicate];
NSArray * results = [context executeFetchRequest：fetchRequest error：& error];
if（结果==零）
{
//处理错误
}
else if（results.count == 0）
{
//无需更新，添加新陷阱
//创建新记录（行）
trapEntity = [NSEntityDescription insertNewObjectForEntityForName：kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext：context];
}
其他
{
trapEntity = results [0]; // ID只能有一个对象。
}
if（trapEntity！= nil）
{
//设置新对象或现有对象的属性...
// Int
[trapEntity setTrapID：[NSNumber numberWithInt：trapObject.getTrapID]];
[trapEntity setType：[NSNumber numberWithInt：trapObject.getTrapType]];
[trapEntity setDist：[NSNumber numberWithInt：trapObject.getTrapDistanceToCar]];
[trapEntity setDist_to_close_point：[NSNumber numberWithInt：trapObject.getTrapDistanceToClosePoint]]；
[trapEntity setActive：[NSNumber numberWithInt：trapObject.isActive]];
[trapEntity setAlert：[NSNumber numberWithInt：trapObject.isAlert]];
[trapEntity setAlarmDistance：[NSNumber numberWithInt：trapObject.alarmDistance]];
[trapEntity setRoadNumber：[NSNumber numberWithInt：trapObject.roadNumber]];
[trapEntity setPolys：[NSNumber numberWithInt：trapObject.polygons]];
[trapEntity setEnter_to_area：[NSNumber numberWithInt：trapObject.getTrapEnterToArea]]；
// Double
[trapEntity setLat：[NSNumber numberWithDouble：trapObject.getTrapLat]] ;;
[trapEntity setLon：[NSNumber numberWithDouble：trapObject.getTrapLon]]；
[trapEntity setClose_point_lat：[NSNumber numberWithDouble：trapObject.getTrapClosePointLat]]；
[trapEntity setClose_point_lon：[NSNumber numberWithDouble：trapObject.getTrapClosePointLon]]；
// NSString
[trapEntity setLastTrapAlarm：[NSString stringWithFormat：@％li，trapObject.getTrapLastAlarm]];
[trapEntity setPoly0：trapObject.getTrapPolygonA];
[trapEntity setPoly1：trapObject.getTrapPolygonB];
[trapEntity setPoly2：trapObject.getTrapPolygonC];
[trapEntity setPolygonAzimut1：trapObject.getTrapPolygonAzimuthA];
[trapEntity setPolygonAzimut2：trapObject.getTrapPolygonAzimuthB];
[trapEntity setPolygonAzimut3：trapObject.getTrapPolygonAzimuthC];
[trapEntity setDesc：trapObject.getTrapDesc];
//所有属性等...
error = nil;
if（[context save：& error] == NO）{
NSLog（@％s错误保存：％@ \n％@，__ PRETTY_FUNCTION __，error.localizedDescription，error.userInfo ）;
}
else {
[重置上下文]；
}
}
}
2：
-
-（void）saveArray：（NSArray *）array
{
kNETROADS_CONTEXT.arrayOfAllTraps = self.arrayOfAllTraps = array.mutableCopy;
NSLog（@陷阱总数：％d，self.arrayOfAllTraps.count）;
NSManagedObjectContext *上下文= generateManagedObjectContext（）;
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *实体= [NSEntityDescription实体名称：kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext：context]；
[fetchRequest setEntity：entity];
NSError *错误=无;
NSArray * fetchedObjects = [上下文executeFetchRequest：fetchRequest错误：&错误];
NSLog（@ TrapService-fetchedObjects.count：％d，fetchedObjects.count）;
if（fetchedObjects == nil || fetchedObjects.count == 0）{
NSLog（@ saveArray-localizedDescription：％@，userInfo：％@，error.localizedDescription，错误。用户信息）;
}
[self readArray];
}
-（void）readArray
{
NSManagedObjectContext * context = generateManagedObjectContext（）;
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *实体= [NSEntityDescription实体名称：kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext：context]；
[fetchRequest setEntity：entity];
NSError *错误=无;
NSArray * fetchedObjects = [上下文executeFetchRequest：fetchRequest错误：&错误];
NSLog（@ readArray-fetchedObjects.count：％d，fetchedObjects.count）;
if（fetchedObjects == nil || fetchedObjects.count == 0）{
NSLog（@ readArray-localizedDescription：％@，userInfo：％@，error.localizedDescription，错误。用户信息）;
}
}
3：
---
-（void）initVariables
{
db = [[DataBase alloc] init];
// dbat = [[DataBaseAllTraps alloc] init];
dbat = [DataBaseAllTraps getInstance];
kRECEIVER_CONTEXT.db = [[数据库分配] init];
[db deleteTrapsTable];
[dbat deleteTrapsTable];
self.dictAddUserLocations = [[NSMutableDictionary alloc] init];
self.arrayOfAllTraps = [Netroads sharedInstance] .arrayOfAllTraps;
self.arrayOfLocations = [[NSMutableArray alloc] init];
self.firstOnLocationChanged = YES;
self.mLocation = [CLLocation新]；
self.mLastLocation = [CLLocation新]；
self.globalLocation = [CLLocation新]；
self.lastGlobalLocation = [CLLocation新]；
self.myLocations = [[NSMutableArray alloc] init];
self.accuracy = @ N / A;
self.closeTrap = [[陷阱分配] init];
self.notification = [NSNotificationCenter defaultCenter];
// // [self.notification addObserver：self选择器：@selector（onReceive :)名称：kSend_To_Receiver_Notification对象：nil];
}
4：
---
-（void）initializeQuadTree
{
self.qTree = [[ QuadTree alloc] init];
BOOL成功=是；
NSManagedObjectContext *上下文= generateManagedObjectContext（）;
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *实体= [NSEntityDescription实体名称：kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext：context]；
[fetchRequest setEntity：entity];
NSError *错误=无;
NSArray * fetchedObjects = [上下文executeFetchRequest：fetchRequest错误：&错误];
if（fetchedObjects == nil || fetchedObjects.count == 0）
{
NSLog（@ initializeQuadTree-localizedDescription：％@，userInfo：％@，error.localizedDescription，错误。用户信息）;
成功=否；
}
NSLog（@ initializeQuadTree-fetchedObjects.count：％d，fetchedObjects.count）;
NSAssert（fetchedObjects！= nil，@错误：fetchedObjects = nil）;
NSAssert（fetchedObjects.count> 0，@错误：fetchedObjects没有记录。）;
如果成功，则
{
for（CoreDataAllTraps * fetchedObjects中的陷阱）
{
double latitude = trap.lat.doubleValue;
double经度= trap.lon.doubleValue;
double closePointLat = trap.close_point_lat.doubleValue;
double closePointLon = trap.close_point_lon.doubleValue;
DummyAnnotation * trapAnnotation = [[DummyAnnotation alloc] init];
if（closePointLat！= 0.0 || closePointLon！= 0.0）trapAnnotation.coordinate = CLLocationCoordinate2DMake（closePointLat，closePointLon）;
else trapAnnotation.coordinate = CLLocationCoordinate2DMake（纬度，经度）;
[self.qTree insertObject：trapAnnotation];
}
}
else
{
for（陷阱* kNETROADS_CONTEXT.arrayOfAllTraps中的陷阱）
{
double latitude = trap.lat;
double longitude = trap.lon;
double closePointLat = trap.closePointLat;
double closePointLon = trap.closePointLon;
DummyAnnotation * trapAnnotation = [[DummyAnnotation alloc] init];
if（closePointLat！= 0.0 || closePointLon！= 0.0）trapAnnotation.coordinate = CLLocationCoordinate2DMake（closePointLat，closePointLon）;
else trapAnnotation.coordinate = CLLocationCoordinate2DMake（纬度，经度）;
[self.qTree insertObject：trapAnnotation];
}
}
NSLog（@陷阱总数（％s）：％i，__ PRETTY_FUNCTION__，成功？fetchedObjects.count：[Netroads sharedInstance] .arrayOfAllTraps.count）；
}
旁注：
*呼叫后initializeQuadTree 我正在初始化位置管理器。
*在位置管理器中，我有一个 dispatch_async ，将整个代码包装在其中。
*完成所有初始化后，代码的主要部分通过位置管理器 didUpdateLocations 进行。
*对于核心数据中的每一次使用，我都会像这样生成新的NSManagedObjectConext：
FOUNDATION_EXPORT NSManagedObjectContext * generateManagedObjectContext （）
{
NSManagedObjectContext * context = [[NSManagedObjectContext alloc] init];
context.persistentStoreCoordinator = appDelegate.persistentStoreCoordinator;
返回上下文；
}
解决方案
[db deleteTrapsTable];
[dbat deleteTrapsTable];
在创建表后将其删除
After I tried to ask twice and explain myself, I did a dig and I think I can now explain my problem better:
1) I'm using core data to save to NSManagedObjects: CoreDataTrap & CoreDataAllTraps.
First time, I'm parsing a large xml and then convert to array and then add the details to CoreDataAllTraps, this operation going well as I know because I did a log.
2) Then, Just for the test, I'm fetching all of the records and log the total number of them.
Those functions give me the correct number of records. 3) Then just initializing a few variables.
4) Then initializing my quad tree.
Which gives me back my assertion error.
Error: fetchedObjects have no records.
5) Then, all the rest of the functions that using core data gives me error back of course, because there is no data.
Relevant (numbered) code:
1:
---
- (void)addOrUpdateTrap:(Traps*)trapObject
{
NSManagedObjectContext *context = generateManagedObjectContext();
int trapID = trapObject.getTrapID;
CoreDataAllTraps *trapEntity = nil;
NSError *error = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:kCORE_DATA_ALL_TRAPS_ENTITY];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"trapID == %d", trapID];
[fetchRequest setPredicate:predicate];
NSArray *results = [context executeFetchRequest:fetchRequest error:&error];
if (results == nil)
{
// Handle error
}
else if (results.count == 0)
{
// Nothing to update, add new trap
// Create a new record (row)
trapEntity = [NSEntityDescription insertNewObjectForEntityForName:kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext:context];
}
else
{
trapEntity = results[0]; // There should be only one object for the ID.
}
if (trapEntity != nil)
{
// Set properties for new or existing object ...
// Int
[trapEntity setTrapID:[NSNumber numberWithInt:trapObject.getTrapID]];
[trapEntity setType:[NSNumber numberWithInt:trapObject.getTrapType]];
[trapEntity setDist:[NSNumber numberWithInt:trapObject.getTrapDistanceToCar]];
[trapEntity setDist_to_close_point:[NSNumber numberWithInt:trapObject.getTrapDistanceToClosePoint]];
[trapEntity setActive:[NSNumber numberWithInt:trapObject.isActive]];
[trapEntity setAlert:[NSNumber numberWithInt:trapObject.isAlert]];
[trapEntity setAlarmDistance:[NSNumber numberWithInt:trapObject.alarmDistance]];
[trapEntity setRoadNumber:[NSNumber numberWithInt:trapObject.roadNumber]];
[trapEntity setPolys:[NSNumber numberWithInt:trapObject.polygons]];
[trapEntity setEnter_to_area:[NSNumber numberWithInt:trapObject.getTrapEnterToArea]];
// Double
[trapEntity setLat:[NSNumber numberWithDouble:trapObject.getTrapLat]];
[trapEntity setLon:[NSNumber numberWithDouble:trapObject.getTrapLon]];
[trapEntity setClose_point_lat:[NSNumber numberWithDouble:trapObject.getTrapClosePointLat]];
[trapEntity setClose_point_lon:[NSNumber numberWithDouble:trapObject.getTrapClosePointLon]];
// NSString
[trapEntity setLastTrapAlarm:[NSString stringWithFormat:@"%li", trapObject.getTrapLastAlarm]];
[trapEntity setPoly0:trapObject.getTrapPolygonA];
[trapEntity setPoly1: trapObject.getTrapPolygonB];
[trapEntity setPoly2: trapObject.getTrapPolygonC];
[trapEntity setPolygonAzimut1: trapObject.getTrapPolygonAzimuthA];
[trapEntity setPolygonAzimut2: trapObject.getTrapPolygonAzimuthB];
[trapEntity setPolygonAzimut3: trapObject.getTrapPolygonAzimuthC];
[trapEntity setDesc: trapObject.getTrapDesc];
// etc. for all properties ...
error = nil;
if ([context save:&error] == NO) {
NSLog(@"%s error saving: %@\n%@", __PRETTY_FUNCTION__, error.localizedDescription, error.userInfo);
}
else {
[context reset];
}
}
}
2:
---
- (void)saveArray:(NSArray*)array
{
kNETROADS_CONTEXT.arrayOfAllTraps = self.arrayOfAllTraps = array.mutableCopy;
NSLog(@"Total number of traps: %d", self.arrayOfAllTraps.count);
NSManagedObjectContext *context = generateManagedObjectContext();
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSError *error = nil;
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
NSLog(@"TrapService - fetchedObjects.count: %d", fetchedObjects.count);
if (fetchedObjects == nil || fetchedObjects.count == 0) {
NSLog(@"saveArray - localizedDescription: %@, userInfo: %@", error.localizedDescription, error.userInfo);
}
[self readArray];
}
- (void)readArray
{
NSManagedObjectContext *context = generateManagedObjectContext();
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSError *error = nil;
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
NSLog(@"readArray - fetchedObjects.count: %d", fetchedObjects.count);
if (fetchedObjects == nil || fetchedObjects.count == 0) {
NSLog(@"readArray - localizedDescription: %@, userInfo: %@", error.localizedDescription, error.userInfo);
}
}
3:
---
- (void)initVariables
{
db = [[DataBase alloc] init];
//dbat = [[DataBaseAllTraps alloc] init];
dbat = [DataBaseAllTraps getInstance];
kRECEIVER_CONTEXT.db = [[DataBase alloc] init];
[db deleteTrapsTable];
[dbat deleteTrapsTable];
self.dictAddUserLocations = [[NSMutableDictionary alloc] init];
self.arrayOfAllTraps = [Netroads sharedInstance].arrayOfAllTraps;
self.arrayOfLocations = [[NSMutableArray alloc] init];
self.firstOnLocationChanged = YES;
self.mLocation = [CLLocation new];
self.mLastLocation = [CLLocation new];
self.globalLocation = [CLLocation new];
self.lastGlobalLocation = [CLLocation new];
self.myLocations = [[NSMutableArray alloc] init];
self.accuracy = @"N/A";
self.closeTrap = [[Traps alloc] init];
self.notification = [NSNotificationCenter defaultCenter];
// [self.notification addObserver:self selector:@selector(onReceive:) name:kSend_To_Receiver_Notification object:nil];
}
4:
---
- (void)initializeQuadTree
{
self.qTree = [[QuadTree alloc] init];
BOOL success = YES;
NSManagedObjectContext *context = generateManagedObjectContext();
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:kCORE_DATA_ALL_TRAPS_ENTITY inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSError *error = nil;
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
if (fetchedObjects == nil || fetchedObjects.count == 0)
{
NSLog(@"initializeQuadTree - localizedDescription: %@, userInfo: %@", error.localizedDescription, error.userInfo);
success = NO;
}
NSLog(@"initializeQuadTree - fetchedObjects.count: %d", fetchedObjects.count);
NSAssert(fetchedObjects != nil, @"Error: fetchedObjects = nil");
NSAssert(fetchedObjects.count > 0, @"Error: fetchedObjects have no records.");
if (success)
{
for (CoreDataAllTraps *trap in fetchedObjects)
{
double latitude = trap.lat.doubleValue;
double longitude = trap.lon.doubleValue;
double closePointLat = trap.close_point_lat.doubleValue;
double closePointLon = trap.close_point_lon.doubleValue;
DummyAnnotation *trapAnnotation = [[DummyAnnotation alloc] init];
if (closePointLat != 0.0 || closePointLon != 0.0) trapAnnotation.coordinate = CLLocationCoordinate2DMake(closePointLat, closePointLon);
else trapAnnotation.coordinate = CLLocationCoordinate2DMake(latitude, longitude);
[self.qTree insertObject:trapAnnotation];
}
}
else
{
for (Traps *trap in kNETROADS_CONTEXT.arrayOfAllTraps)
{
double latitude = trap.lat;
double longitude = trap.lon;
double closePointLat = trap.closePointLat;
double closePointLon = trap.closePointLon;
DummyAnnotation *trapAnnotation = [[DummyAnnotation alloc] init];
if (closePointLat != 0.0 || closePointLon != 0.0) trapAnnotation.coordinate = CLLocationCoordinate2DMake(closePointLat, closePointLon);
else trapAnnotation.coordinate = CLLocationCoordinate2DMake(latitude, longitude);
[self.qTree insertObject:trapAnnotation];
}
}
NSLog(@"TOTAL NUMBER OF TRAPS (%s): %i", __PRETTY_FUNCTION__, success?fetchedObjects.count:[Netroads sharedInstance].arrayOfAllTraps.count);
}
Side notes:
* After calling initializeQuadTree i'm initializing the location manager.
* In location manager I've a dispatch_async that wrap the whole code inside.
* After I done with all initializing, the main of the code happens via location manager didUpdateLocations.
* For each and every using in core data I'm generating new NSManagedObjectConext like this:
FOUNDATION_EXPORT NSManagedObjectContext *generateManagedObjectContext()
{
NSManagedObjectContext *context = [[NSManagedObjectContext alloc] init];
context.persistentStoreCoordinator = appDelegate.persistentStoreCoordinator;
return context;
}
解决方案
[db deleteTrapsTable];
[dbat deleteTrapsTable];
The table deleted after you create it
这篇关于NSManagedObjectContext只能运行几次，然后停止工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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