CoreData + UIViewController + UITableView

时间：2016-03-20 19:05:04

标签： ios objective-c uitableview core-data uiviewcontroller

我想解释一下我面临的最详细的问题。 以前我没有直接使用UITableView控件的UIViewController，问题是现在我需要在视图中显示更多内容，只是tableview所以我创建了一个新视图。现在我有一个UIViewController，它有：UIScrollView。其中包括：1。UIView + 1 UITableView

我正在使用AutoLayout。并且工作正常。我面临的问题是，由于我切换到使用此视图，因此我无法使用coredata显示表格中的内容。我能够在没有coredata但没有coredata的情况下做到这一点。 在interfacebuilder中，我设置数据源并委托给这个UIViewController。

部首：

#import <UIKit/UIKit.h>

@interface ResultsExtraVC : UIViewController <UITableViewDelegate, UITableViewDataSource>
@property(nonatomic, strong) AGTCoreDataStack *model;
@property (strong, nonatomic) IBOutlet UILabel *labelRaceTime;
@property (strong, nonatomic) IBOutlet UILabel *labelTrackCondition;
@property (strong, nonatomic) IBOutlet UILabel *labelRaceStarttime;
@property (strong, nonatomic) IBOutlet UILabel *labelRaceMode;
@property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) IBOutlet UITableView *tableView;
@property (strong, nonatomic) IBOutlet UIView *raceInfoView;
@property(nonatomic, strong)NSNumber *eventID;
@property(nonatomic, strong)NSNumber *sectionID;
@property(nonatomic, strong)NSNumber *elementID;
@property(nonatomic, strong)NSNumber *categoryID;
@end

实现：

#import "ResultsExtraVC.h"
#import "ResultsExtraCellVC.h"
#import "Result.h"
#import "Element.h"
#import "Section.h"
#import <CoreData/CoreData.h>

@interface ResultsExtraVC () <NSFetchedResultsControllerDelegate>
//Core data
@property (nonatomic,strong) NSManagedObjectContext* managedObjectContext;
@property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;
@end
static NSString * const cellIdentifier = @"resultsExrtaAltCell";


@implementation ResultsExtraVC
@synthesize managedObjectContext;
@synthesize fetchedResultsController = _fetchedResultsController;
@synthesize eventID, sectionID, elementID, categoryID, model;

- (void)viewDidLoad {
    [super viewDidLoad];
    managedObjectContext = self.model.context;

    [self getResults];

    NSLog(@"ElementName: %@", [self getElementName]);
    NSLog(@"SectionName: %@", [self getSectionName]);
    [self configureHeatInfo];
    // Do any additional setup after loading the view.
}
- (void)viewDidUnload
{
    [super viewDidUnload];

    self.fetchedResultsController = nil;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
#pragma mark - View Configuration
-(void) configureHeatInfo{
    _scrollView.backgroundColor = [UIColor cyanColor];
    _scrollView.translatesAutoresizingMaskIntoConstraints = NO;

    _labelRaceTime.translatesAutoresizingMaskIntoConstraints = NO;
    _labelRaceTime.text = @"Race time:\n10:00";

    _labelRaceMode.translatesAutoresizingMaskIntoConstraints = NO;
    _labelRaceMode.text = @"Mode: Groupstart";

    _labelTrackCondition.translatesAutoresizingMaskIntoConstraints = NO;
    _labelTrackCondition.text = @"Track Condition: Dry";

    _labelRaceStarttime.translatesAutoresizingMaskIntoConstraints = NO;
    _labelRaceStarttime.text = @"Starttime: 12.03.2016 11:09:10";

    //self.tableView.translatesAutoresizingMaskIntoConstraints = NO;
    /*self.tableView.dataSource = self;
      self.tableView.delegate = self;*/
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return [[self.fetchedResultsController sections] count];
}

/*- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return 20;
}*/
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    id  sectionInfo = [[_fetchedResultsController sections] objectAtIndex:section];
    #ifndef NDEBUG
        NSLog(@"%s (line:%d) - Rows: %lu",__PRETTY_FUNCTION__,__LINE__, (unsigned long)[sectionInfo numberOfObjects]);
    #endif
    // Return the number of rows in the section.

    return [sectionInfo numberOfObjects];
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    return [self basicCellAtIndexPath:indexPath];
}
- (ResultsExtraCellVC *)basicCellAtIndexPath:(NSIndexPath *)indexPath {
    ResultsExtraCellVC *cell = [self.tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    // Using a cell identifier will allow your app to reuse cells as they come and go from the screen.
    if (cell == nil) {
        #ifndef NDEBUG
            NSLog(@"%s (line:%d)",__PRETTY_FUNCTION__,__LINE__);
        #endif
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"ResultsExtraCell" owner:self options:nil];
        cell = (ResultsExtraCellVC *)[nib objectAtIndex:0];
    }
    [self configureCell:cell atIndexPath:indexPath];

    return cell;
}

- (void)configureCell:(ResultsExtraCellVC *)cell atIndexPath:(NSIndexPath *)indexPath {
    #ifndef NDEBUG
        NSLog(@"%s (line:%d)",__PRETTY_FUNCTION__,__LINE__);
    #endif

    Result *result = [_fetchedResultsController objectAtIndexPath:indexPath];

    [cell.cellRankNr setText:[NSString stringWithFormat:@"%@",[result endposition]]];
    [cell.cellName setText:[NSString stringWithFormat:@"%@ %@ (%@)",[result pilotprename], [result pilotname], [result carnumber]]];
    [cell.cellResult setText:[NSString stringWithFormat:@"%@",NSLocalizedFormatString(@"LapsXnTimeX",[result rlaps],[result rendtime])]];
    [cell.cellRace setText:[NSString stringWithFormat:@"%@",NSLocalizedFormatString(@"BestTimeXnAvgTimeX",[result rbesttime], [result rmediumtime])]];

}

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{

    if ([tableView respondsToSelector:@selector(setSeparatorInset:)])
    {
        [tableView setSeparatorInset:UIEdgeInsetsZero];
    }

    if ([tableView respondsToSelector:@selector(setLayoutMargins:)])
    {
        [tableView setLayoutMargins:UIEdgeInsetsZero];
    }

    if ([cell respondsToSelector:@selector(setLayoutMargins:)])
    {
        [cell setLayoutMargins:UIEdgeInsetsZero];
    }
}



-(NSString *)getElementName{
    NSString *elementName = @"";

    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Elements" inManagedObjectContext:managedObjectContext];
    NSFetchRequest *request = [[NSFetchRequest alloc] init] ;
    [request setEntity:entityDescription];

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(eventid = %@ AND sectionid = %@ AND elementid = %@ AND categoryid= %@)",eventID, sectionID, elementID, categoryID];
    [request setPredicate:predicate]; //added this line later
    NSArray *array = [managedObjectContext executeFetchRequest:request error:nil];
    if([array count]> 0){
        Element *element = [array lastObject];
        elementName = [element name];
    }
    return elementName;
}

-(NSString *)getSectionName{
    NSString *sectiontName = @"";

    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Sections" inManagedObjectContext:managedObjectContext];


    NSFetchRequest *request = [[NSFetchRequest alloc] init] ;
    [request setEntity:entityDescription];

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(eventid = %@ AND sectionid = %@)",eventID, sectionID];
    [request setPredicate:predicate]; //added this line later
    NSArray *array = [managedObjectContext executeFetchRequest:request error:nil];
    if([array count]> 0){
        Section *section = [array lastObject];
        sectiontName = [section name];
    }
    return sectiontName;
}

-(void)getResults{
    // Initialize Fetch Request
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Results"];

    // Add Sort Descriptors
    //[fetchRequest setSortDescriptors:@[[NSSortDescriptor sortDescriptorWithKey:@"endposition" ascending:YES]]];

    //Predicate
    NSPredicate *commentsPredicate = [NSPredicate predicateWithFormat:@"(eventid = %@ AND sectionid = %@ AND elementid = %@)",eventID, sectionID, elementID];
    [fetchRequest setPredicate:commentsPredicate]; //added this line later

    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"endposition"
                                                                   ascending:YES];
    NSArray *sortDescriptors = @[sortDescriptor];

    [fetchRequest setSortDescriptors:sortDescriptors];

    // Initialize Fetched Results Controller
    self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];

    // Configure Fetched Results Controller
    [self.fetchedResultsController setDelegate:self];

    // Perform Fetch
    NSError *error = nil;
    [self.fetchedResultsController performFetch:&error];

    if (error) {
        NSLog(@"Unable to perform fetch.");
        NSLog(@"%@, %@", error, error.localizedDescription);
    }
}
#pragma mark -
#pragma mark Fetched Results Controller Delegate Methods
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
    [self.tableView beginUpdates];
}

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
    [self.tableView endUpdates];
}

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {
    switch (type) {
        case NSFetchedResultsChangeInsert: {
            [self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
        }
        case NSFetchedResultsChangeDelete: {
            [self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
        }
        case NSFetchedResultsChangeUpdate: {
            [self configureCell:(ResultsExtraCellVC *)[self.tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            break;
        }
        case NSFetchedResultsChangeMove: {
            [self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
            [self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
        }
    }
}
@end

我的视图如下所示： enter image description here

我尝试按照一些教程，因为这是我第一次使用CoreData执行此操作，以前我总是只使用UITableViewController。 我跟着这个：http://code.tutsplus.com/tutorials/core-data-from-scratch-more-nsfetchedresultscontroller--cms-21777 并检查：CoreData TableView inside UIViewController

但没有成功。 如果有人可以帮我解决这个问题，我会很棒。

提前致谢

1 个答案:

答案 0 :(得分：0)

可能在代码行中

// Initialize Fetched Results Controller
self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];

sectionNameKeyPath丢失了？它必须是NSSortDescriptor个键之一。

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