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Editorial Team
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Asked: 2026-05-18T00:23:42+00:00

I have been working on a problem relating to UITableView and cellForRowAtIndexPath. I want

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I have been working on a problem relating to UITableView and cellForRowAtIndexPath.

I want to give the user the ability to have a very large number of rows much like a large list of email on iPhone. I discovered this problem when I began to create a class that would queue and dequeue groups of records from the database, as needed, in order to conserve memory. I found that when my UITableViewController loads, it then calls cellForRowAtIndexPath for the typical first 10 indexes (0 through 9). The problem ocurrs when I either click my mouse on the simulator’s black outer surface area or I attempt to scroll down on the UITableView using an upward gesture. At this point, cellForRowAtIndexPath gets called for all remaining indexes. This happens even if there are 1000+ cells. I have attempted recreating a VERY SIMPLE project with only 100 indexes (nothing fancy). It does exactly the same thing.. as soon as I scroll, it calls cellForRowAtIndexPath from positions 10 to 99.

Is this the normal behavior of a UITableView? Does anyone anyone have any ideas why it is inefficiently calling all rows?

I will say that once this initial pass occurs, it seems like it begins to work correctly. I am really puzzled by this because it makes it almost impossible to create a class for queuing and de-queuing records as need.

Here is the code on my much simpler sample project:

// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}


// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
 return 100;
}


// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {


 printf("RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = %d\n", indexPath.row);


    static NSString *CellIdentifier = @"Cell";

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

 cell.textLabel.text = @"Example Text";

 return cell;  
}

Console:

……
Initial Load of View
……

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 0

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 1

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 2

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 3

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 4

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 5

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 6

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 7

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 8

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 9

……
First Scroll Gesture
……

ootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 11

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 12

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 13

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 14

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 15

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 16

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 17

.
.
I removed a few here to shorten it up
.
.

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 97

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 98

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 99

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 10

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 11

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 12

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 13

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 14

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 15

RootViewController, -tableView:cellForRowAtIndexPath; // indexPath.row = 16

(gdb)

Thanks for your help.

Eric

Edit (subsequent day) –> Today I thought to try a real device instead of my simulator. My iPhone 3GS does not reproduce this strange behavior. I believe there might be something wrong with the simulator on my machine. I plan to try another MAC when time permits.

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1 Answer

  1. Editorial Team

    The cause of this problem was an application I have installed on my Mac called Cinch.

    Cinch is a window management application that adds a windows ‘snap’ feature to Mac OS. The program works great otherwise. Whenever I am working with cellForRowAtIndex path, I’ll just have to remember to disable Cinch.

    Sadly, I had to reload my entire computer to figure this out! Hope this is helpful to anyone else experiencing this weird functionality.

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