UITableView不会在reloadData上重新加载

Question

I created a Table View in my Storyboard and am trying to populate the rows in my ViewController. When I call [self.tableView], it doesn't refresh the content (it doesn't call cellForRowAtIndexPath).

SetListViewController.h:

#import <UIKit/UIKit.h>

@interface SetListViewController : UITableViewController

@end

SetListViewController.m

#import "SetListViewController.h"
#import "SetCell.h"
#import "Set.h"

@interface SetListViewController () <UITableViewDataSource, UITableViewDelegate>
{
    NSMutableArray *userSets; // array containing all the user's set objects
}
@implementation SetListViewController

- (void)viewDidLoad {
   [super viewDidLoad];
   self.userSets = [[NSMutableArray alloc] init];
   [self.tableView setDataSource:self];
   [self.tableView setDelegate:self];
   // load sets
   [self fetchSets];
}

- (void)fetchSets{
        for(NSDictionary *currentSet in set){
           Set *userSet = [[Set alloc] init];
           userSet.name = [currentSet objectForKey:@"name"];
           [userSets addObject:UserSet];
        }
       [self.tableView reloadData];
    }

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return self.userSets.count;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.userSets.count;
}

- (SetCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"in cellForRowAtIndexPath");
    SetCell *cell = [tableView dequeueReusableCellWithIdentifier:@"setCell" forIndexPath:indexPath];
    NSDate *object = self.userSets[indexPath.row];
    cell.setTitleLabel.text = [object description];
    NSLog(@"setTitleLabel: %@", cell.setTitleLabel);
    return cell;
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
    // Return NO if you do not want the specified item to be editable.
    return YES;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        NSLog(@"deleting set");
        [self deleteSet:(NSString *)[self.userSets objectAtIndex:indexPath.row]];
        NSLog(@"set ID: %@", [self.userSets objectAtIndex:indexPath.row]);
        [self.userSets removeObjectAtIndex:indexPath.row];
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    } else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
    }
}
@end

What am I doing wrong?

Answer 1

I think the problem is that you have a property called userSets, but also an ivar called userSets (I'm assuming you have a property even though you don't show it, since using self.userSets would give you an error otherwise). In viewDidLoad you instantiate the property, but in fetchSets you try to populate the ivar, with [userSets addObject:UserSet] -- but you never initialized that array. You should get rid of the ivar, and always refer to your property as self.userSets.

Answer 2

Have you implemented the dataSouce methods of the table view: (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView;

and

(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;

Please make sure to implement above dataSouce methods of UITableView

Answer 3

first create the nib file with UIViewController. In your .h file set the following

#import <UIKit/UIKit.h>

@interface SimpleTableViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>

@end

In your .m file do the following

@implementation SimpleTableViewController
{
    NSArray *tableData;
}


- (void)viewDidLoad
{
    [super viewDidLoad];
    // Initialize table data
    tableData = [NSArray arrayWithObjects:@"Egg Benedict", @"Mushroom Risotto", @"Full Breakfast", @"Hamburger", @"Ham and Egg Sandwich", @"Creme Brelee", @"White Chocolate Donut", @"Starbucks Coffee", @"Vegetable Curry", @"Instant Noodle with Egg", nil];
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [tableData count];
}

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

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];
    }

    cell.textLabel.text = [tableData objectAtIndex:indexPath.row];
    return cell;
}

In your .xib file do the following

Try this out and reply what you found