Question

我找到了实现section collapsable / expandible tableView所需的方法，但是它从代码本身填充了行对象。我刚刚创建了一个核心数据实体，并希望知道用它填充行对象。我需要帮助转换这个特定的代码，让我添加核心数据对象。这是我目前的代码：

    //

#import "CollapsableTableViewViewController.h"
#import "CollapsableTableView.h"
#import "CollapsableTableViewAppDelegate.h"


@interface CollapsableTableViewViewController()
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
@end


@implementation CollapsableTableViewViewController
@synthesize fetchedResultsController = _fetchedResultsController;

/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
    //1
    CollapsableTableViewAppDelegate* appDelegate = [UIApplication sharedApplication].delegate;
    //2
    self.managedObjectContext = appDelegate.managedObjectContext;


      self.fetchedResultsController = nil;
    NSError *error;
    if (![[self fetchedResultsController] performFetch:&error]) {
        // Update to handle the error appropriately.
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        exit(-1);  // Fail
    }







    CollapsableTableView* tableView = (CollapsableTableView*) myTableView;
    tableView.collapsableTableViewDelegate = self;

//    [tableView setIsCollapsed:YES forHeaderWithTitle:@"First Section"];
//    [tableView setIsCollapsed:YES forHeaderWithTitle:@"Second Section"];
//    [tableView setIsCollapsed:YES forHeaderWithTitle:@"Third Section"];
//    [tableView setIsCollapsed:YES forHeaderWithTitle:@"Fourth Section"];
//    [tableView setIsCollapsed:YES forHeaderWithTitle:@"Fifth Section"];
}


// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return YES;
}

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    [spinner release];
    spinner = nil;
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [spinner release];
    [super dealloc];
}


#pragma mark -
#pragma mark UITableViewDataSource

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 10;
}


+ (NSString*) titleForHeaderForSection:(int) section
{
    switch (section)
    {
        case 0 : return @"First Section";
        case 1 : return @"Second Section";
        case 2 : return @"Third Section";
        case 3 : return @"Fourth Section";
        case 4 : return @"Fifth Section";
        default : return [NSString stringWithFormat:@"Section no. %i",section + 1];
    }
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    return [CollapsableTableViewViewController titleForHeaderForSection:section];
}

// Uncomment the following two methods to use custom header views.
//- (UILabel *) createHeaderLabel: (UITableView *) tableView :(NSString *)headerTitle {
//    UILabel *titleLabel = [[[UILabel alloc] initWithFrame:CGRectZero] autorelease];
//    titleLabel.frame =CGRectMake(0, 0, tableView.frame.size.width - 20, 60);
//    titleLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;
//    titleLabel.backgroundColor = [UIColor clearColor];
//    titleLabel.textColor = [UIColor whiteColor];
//    titleLabel.font=[UIFont fontWithName:@"Helvetica-Bold" size:20];
//    titleLabel.text = headerTitle;
//    titleLabel.textAlignment = UITextAlignmentRight;
//    return titleLabel;
//}
//
//- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
//{
//    // create the parent view that will hold header Label
//    UIView * customView = [[[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, tableView.frame.size.width , 60)]autorelease];
//    UILabel *titleLabel;
//    titleLabel = [self createHeaderLabel: tableView :[CollapsableTableViewViewController titleForHeaderForSection:section]];
//    
//    [customView addSubview:titleLabel];
//    
//    UILabel* collapsedLabel = [[[UILabel alloc] initWithFrame:CGRectMake(10,0,50,60)] autorelease];
//    collapsedLabel.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;
//    collapsedLabel.backgroundColor = [UIColor clearColor];
//    collapsedLabel.textColor = [UIColor whiteColor];
//    collapsedLabel.text = @"-";
//    collapsedLabel.tag = COLLAPSED_INDICATOR_LABEL_TAG;
//    [customView addSubview:collapsedLabel];
//    
//    customView.tag = section;
//    customView.backgroundColor = [UIColor blackColor];
//    return customView;
//}

//- (NSString*) tableView:(UITableView *)tableView titleForFooterInSection:(NSInteger)section
//{
//    return [NSString stringWithFormat:@"Footer %i",section + 1];
//}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    switch (section)
    {
        case 2 : return 0;
        case 3 : return 30;
        default : return 8;
    }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }

    // Configure the cell.

    switch (indexPath.row)
    {
        case 0 : cell.textLabel.text = @"First Cell"; break;
        case 1 : cell.textLabel.text = @"Second Cell"; break;
        case 2 : cell.textLabel.text = @"Third Cell"; break;
        case 3 : cell.textLabel.text = @"Fourth Cell"; break;
        case 4 : cell.textLabel.text = @"Fifth Cell"; break;
        case 5 : cell.textLabel.text = @"Sixth Cell"; break;
        case 6 : cell.textLabel.text = @"Seventh Cell"; break;
        case 7 : cell.textLabel.text = @"Eighth Cell"; break;
        default : cell.textLabel.text = [NSString stringWithFormat:@"Cell %i",indexPath.row + 1];
    }

    //cell.detailTextLabel.text = ...;

    return cell;
}


#pragma mark -
#pragma mark CollapsableTableViewDelegate

- (void) collapsableTableView:(CollapsableTableView*) tableView willCollapseSection:(NSInteger) section title:(NSString*) sectionTitle headerView:(UIView*) headerView
{
    [spinner startAnimating];
}

- (void) collapsableTableView:(CollapsableTableView*) tableView didCollapseSection:(NSInteger) section title:(NSString*) sectionTitle headerView:(UIView*) headerView
{
    [spinner stopAnimating];
}

- (void) collapsableTableView:(CollapsableTableView*) tableView willExpandSection:(NSInteger) section title:(NSString*) sectionTitle headerView:(UIView*) headerView
{
    [spinner startAnimating];
}

- (void) collapsableTableView:(CollapsableTableView*) tableView didExpandSection:(NSInteger) section title:(NSString*) sectionTitle headerView:(UIView*) headerView
{
    [spinner stopAnimating];
}


#pragma mark -
#pragma mark IBAction methods

- (IBAction) toggleSection2
{
    NSString* sectionTitle = //[NSString stringWithFormat:@"Tag %i",1]; // Use this expression when using custom header views.
        [CollapsableTableViewViewController titleForHeaderForSection:1]; // Use this expression when specifying text for headers.
    CollapsableTableView* collapsableTableView = (CollapsableTableView*) myTableView;
    BOOL isCollapsed = [[collapsableTableView.headerTitleToIsCollapsedMap objectForKey:sectionTitle] boolValue];
    [collapsableTableView setIsCollapsed:! isCollapsed forHeaderWithTitle:sectionTitle];
}

- (NSFetchedResultsController *)fetchedResultsController {

    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription
                                   entityForName:@"ToDoItems" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];

    NSSortDescriptor *sort = [[NSSortDescriptor alloc]
                              initWithKey:@"tdText" ascending:NO];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];

    [fetchRequest setFetchBatchSize:20];

    NSFetchedResultsController *theFetchedResultsController =
    [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
                                        managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil
                                                   cacheName:@"Root"];
    self.fetchedResultsController = theFetchedResultsController;
    _fetchedResultsController.delegate = self;

    return _fetchedResultsController;

}



@end

要向我的应用添加核心数据，我已完成以下操作：

1. Added CoreDataFramework to the project.
2. Added   #import <CoreData/CoreData.h> to the prefix.pch file
3. Added 
@property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel;
@property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext;
@property (nonatomic, retain, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator ;
to my AppDelegate.h file
4. Added 
@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;

@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

到我的AppDelegate.m文件。

5. Added 
//core data
// 1
- (NSManagedObjectContext *) managedObjectContext {
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }
    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        _managedObjectContext = [[NSManagedObjectContext alloc] init];
        [_managedObjectContext setPersistentStoreCoordinator: coordinator];
    }

    return _managedObjectContext;
}

//2
- (NSManagedObjectModel *)managedObjectModel {
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }
    _managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];

    return _managedObjectModel;
}

//3
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
    if (_persistentStoreCoordinator != nil) {
        return _persistentStoreCoordinator;
    }
    NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory]
                                               stringByAppendingPathComponent: @"Model.sqlite"]];
    NSError *error = nil;
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]
                                   initWithManagedObjectModel:[self managedObjectModel]];
    if(![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                                  configuration:nil URL:storeUrl options:nil error:&error]) {
        /*Error for store creation should be handled in here*/
    }

    return _persistentStoreCoordinator;
}

- (NSString *)applicationDocumentsDirectory {
    return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}

到我的AppDelegate.m文件

6. Updated VC as new edited above in the question.

Answer 1

我发现使用UITableView的CoreData的最佳开端实际上是基于Xcode模板“启用了核心数据的主要详细信息应用程序”的新“从头开始”项目。在此模板中，您将看到所有必须使用CoreData实体填充UITableView的样板代码。

enter image description here

相信我：有太多的基础设施要做 - 你无法“猜测”这段代码或者从API描述中获取，或者从其他地方读取。但是，如果您打开现有项目和这个新模板项目。然后慢慢滚动MasterViewController的代码并复制＆amp;粘贴所有你需要的。这将为您提供一个非常快速的开始。

至少它在同样的情况下对我有用。

将核心数据添加到现有tableView

1 个答案: