Question

I am trying to re-use cellViews using tags and Cell Identifiers, however the code below crashes whenever a cell is re-used. I think I’m almost there. Can anyone see the mistake?

// Customize the appearance of table view cells.
    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    const NSInteger BUTTON_TAG = 1001;
    const NSInteger SWITCH_TAG = 1002;
    const NSInteger TEXTFIELD_TAG = 1003;

    NSString *CellIdentifier = @"";
    if(indexPath.section == 2 && indexPath.row == 0)
        CellIdentifier = @"Button";
    else if (indexPath.section == 3)
        CellIdentifier = @"Switch";
    else
        CellIdentifier = @"TextField";


    UISwitch *switchView;
    UITextField *textField;

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        if (CellIdentifier == @"TextField")
        {
            cell.selectionStyle = UITableViewCellSelectionStyleNone;
            CGRect frame = CGRectInset([cell.contentView bounds], 70, 10);
            textField = [[[UITextField alloc] initWithFrame:frame] autorelease];
            textField.keyboardType = UIKeyboardTypeDefault;
            textField.returnKeyType = UIReturnKeyDone;
            textField.autocorrectionType = UITextAutocorrectionTypeNo;
            textField.autocapitalizationType = UITextAutocapitalizationTypeNone;
            textField.delegate = self;

            cell.accessoryView = textField;
            cell.tag = TEXTFIELD_TAG;

        }
        else if (CellIdentifier == @"Button")
        {
            cell.selectionStyle = UITableViewCellSelectionStyleBlue;
            cell.textLabel.textAlignment = UITextAlignmentCenter;
            cell.clipsToBounds=YES;
            cell.tag = BUTTON_TAG;
        }
        else if (CellIdentifier == @"Switch")
        {
            cell.selectionStyle = UITableViewCellSelectionStyleNone;
            switchView = [[[UISwitch alloc] initWithFrame:CGRectZero] autorelease];

            cell.accessoryView = switchView;
            cell.tag = SWITCH_TAG;
        }
    }
    else
    {
        textField = (UITextField*)[cell viewWithTag:TEXTFIELD_TAG];
        switchView = (UISwitch*)[cell viewWithTag:SWITCH_TAG];     
    }

Crash Log

2012-02-22 14:50:08.352 ***[2304:207] -[UITableViewCell setSecureTextEntry:]: unrecognized selector sent to instance 0x6368270
2012-02-22 14:50:08.355 ***[2304:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UITableViewCell setSecureTextEntry:]: unrecognized selector sent to instance 0x6368270'

Answer 1

You don’t say what the crash is or provide a backtrace, but one problem I see right away is that you are always doing:

switchView = (UISwitch*)[cell viewWithTag:SWITCH_TAG];     

for all recycled cells even though only one of the three types has a switchView.

You also only set TEXTFIELD_TAG for one kind of cell as well, yet refer to it when accessing all types of “recycled” cells.

EDITED TO ADD: I see you’ve added the exception from your console. The exception is being thrown on a call to setSecureTextEntry. I don’t see setSecureTextEntry anywhere in the code you copy & pasted into the question, so I’d suggest looking for setSecureTextEntry in your real code and wherever it’s being called, make sure it’s a UITextField receiving that call and not a UITableViewCell (which can be the super view in which a secure UITextField lives).