在TableView自定义单元格中刷新数组

Question

I have a ViewController that has a TableView generated with Custom Cells. Each Custom Cell has a NSDictionary that generates few arrays.

I want to find the way to replace one array in Custom Cell using [myArray replaceObjectAtIndex:... withObject:...] pointing towards a specific cell in a TableView , provided that I already know the indexPath of that cell that contains that array.

Another words I have to somehow indicate that Custom Cell indexPath, get there and refresh array.

Is there a way to accomplish that mission in Objective-C?

Answer 1

You can get a cell reference using cellForRowAtIndexPath call if you know the indexPath of the cell that you want to change if each of your custom cell is different unique.

But I strongly recommend changing the data model by getting it using cell location as the reference. Because table views reuse cell you could end up with unexpected results. You should instead change your table model and then reload the table or perhaps reload just the specific cells that have changed.

Answer 2

Once you have the indexPath of your cell, you can do something like:

[self.tableView beginUpdates];
[self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPathOfYourCell, nil] withRowAnimation:UITableViewRowAnimationNone];
[self.tableView endUpdates]; 

Answer 3

You got several option for reloading the UITableView taken inside the UIViewController

say your table view is such

    UITableView *tableView

case 1: Reload the whole table view appledoc

[tableView reloadData];

case 2: Reload all the rows inside a section appledoc

[tableView reloadRowsAtIndexPaths:yourIndexPath withRowAnimation: UITableViewRowAnimationNone];

case 3: Reload multiple section at once appledoc

tableView reloadSections:yourIndexPathSet withRowAnimation:UITableViewRowAnimationNone];

NB :: must do any of these operation in your mainThread / gui thread .

Answer 4

Solution.

First, we need to make sure that every Custom Cell has a @property NSInteger cellIndex; . When tableView populates Custom Cells, make sure to add cell.cellIndex = indexPath.row; . That way every Custom Cell will have it equal to tableView row.

Second, when making changes in parent viewController, in the end of update we post notification [[NSNotificationCenter defaultCenter] postNotificationName:@"refreshCollectionView" object:self]; .

Third, in Custom Cell we listen to that notification: [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(refreshCollect) name:@"refreshCollectionView" object:nil]; . That triggers method (also included in Custom Cell) with reference to cellIndex:

-(void) refreshCollect {

    if (cellIndex == [[[NSUserDefaults standardUserDefaults] valueForKey:@"cellIndex"] intValue]) {

       NSURL *newsImgURL = [NSURL URLWithString:[NSString stringWithFormat:@"http://www.website.com/core/functions/ios/page.news.image?news_id=%@", [[NSUserDefaults standardUserDefaults] valueForKey:@"newsID"]]];
       NSData *newsImgData = [NSURLConnection sendSynchronousRequest:[NSURLRequest requestWithURL:newsImgURL] returningResponse:nil error:nil];

       newsImgDict    = [NSJSONSerialization JSONObjectWithData:newsImgData options: NSJSONReadingMutableContainers error:nil];
       newsImgID2     = [NSMutableArray arrayWithArray: [newsImgDict valueForKey:@"image_id"]];
       newsImgTime    = [NSMutableArray arrayWithArray: [newsImgDict valueForKey:@"timestamp"]];
       newsIDImg      = [NSMutableArray arrayWithArray: [newsImgDict valueForKey:@"news_id"]];
       newsImgDescr   = [NSMutableArray arrayWithArray: [newsImgDict valueForKey:@"description"]];
       newsImgExt2    = [NSMutableArray arrayWithArray: [newsImgDict valueForKey:@"ext"]];

} } 

In my case I have NSDictionary that rebuilds some arrays just for that particular Custom Cell.