Question

I have a nice bug here, specially in slow devices.
I have a UITableView jusk like the ones in the App Store app, with a Load More button at the bottom.
When it is pressed, I load the new info from the server, set the array, and reload the table view. In that info is also the url of the image for each object displayed in the table rows, so when we got it we start donwloading the image. When the image is loaded, I reload the row of the object.

[self.searchResultsTableView reloadRowsAtIndexPaths: [NSArray arrayWithObject: path] withRowAnimation: UITableViewRowAnimationNone];

The problem comes when the row is being reloading because the image was downloaded, and the whole table is doing so cause the user pressed the load more button and more info was gotten. Then I get this error:

Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (140) must be equal to the number of rows contained in that section before the update (125), plus or minus the number of rows inserted or deleted from that section (1 inserted, 1 deleted).

Which is perfectly understable, the table was enlarged while the new image row was being updated.
My question is: how can lock it so I do not reload that row until the whole table is reloaded? It would nice something like table.isReloading. I try with a boolean lock, and doing both actions in the main thread, but it did not work …
Thanks a lot.

Answer 1

Well, a little research in the doc put some more light in all this.

reloadRowsAtIndexPaths:withRowAnimation: Call this method if you want to alert the user that the value of a cell is changing. If, however, notifying the user is not important—that is, you just want to change the value that a cell is displaying—you can get the cell for a particular row and set its new value.

And that is what I did, I got the cell and set the new value for image, instead of reloading the whole of it. I guess it is more efficient also:

AHMyTableViewCell *cell = (AHMyTableViewCell *) [self.myTableView cellForRowAtIndexPath:path];

                if ((cell != nil) && ([cell  isKindOfClass:[AHMyTableViewCell class]]))
                    cell.myImageView.image = image;

It does not crash now.