Custom UITableViewCell weird behavior with fast scroll - ios

Question

I have a grouped tableView with 5 sections. The tableView uses a custom UITableViewCell with 2 label and 4 buttons in it. When i select 1 or more buttons at the beginning of the table and then scroll to the end of it, i find those buttons selected in the last cell, sometimes in the second-last. It seems to me that there is some issues with the dequeueReusableCellWithIdentifier but i cannot figure it out.
For clarity i have this code in my viewDidLoad:
// table cell
UINib *nib = [UINib nibWithNibName:#"SMRateMeetingTableViewCell" bundle:nil];
[self.tableView registerNib:nib forCellReuseIdentifier:#"SMRateMeetingTableViewCell"];
and this in my cellForRowAtIndexPath:
SMRateMeetingTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"SMRateMeetingTableViewCell" forIndexPath:indexPath];
// Configure the cell...
if (cell == nil) {
cell = [[SMRateMeetingTableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"SMRateMeetingTableViewCell"];
}
Pretty basic stuff.
I added some screens for better understanding.
EDIT: adding buttons code.
For an easier analysis let's assume i only have 1 button in the custom cell
This is the table view code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
SMRateMeetingTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"SMRateMeetingTableViewCell" forIndexPath:indexPath];
// Configure the cell...
if (cell == nil) {
cell = [[SMRateMeetingTableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"SMRateMeetingTableViewCell"];
}
//the tag will allow me to understand in which section is the button
cell.firstYesButton.tag = indexPath.section;
[cell.firstYesButton addTarget:self action:#selector(firstYesButtonAction:) forControlEvents:UIControlEventTouchUpInside];
return cell;
}
And the relative method associated to the button:
-(IBAction)firstYesButtonAction:(id)sender
{
UIButton *senderButton = (UIButton *)sender;
[self.votesArray replaceObjectAtIndex:(senderButton.tag*2) withObject:[NSNumber numberWithInt:1]];
//NSLog(#"%#", self.votesArray );
}
An this is the code in the implementation file of the custom cell:
#implementation SMRateMeetingTableViewCell
- (void)awakeFromNib {
// Initialization code
[self.firstYesButton setImage:[UIImage imageNamed:#"yesRateDisable.png"] forState:UIControlStateNormal];
}
- (IBAction)firstYesAction:(id)sender {
[self.firstYesButton setImage:[UIImage imageNamed:#"yesRateEnable.png"] forState:UIControlStateNormal];
}

Answer 1

This is because the table view is recycling your cell. This is what the dequeueReusableCellWithIdentifier: method is doing. Because it is recycling views instead of a new one always being created, you will have to set certain properties, such as the selected state of your buttons, otherwise they will retain the properties that they had when they were enqueued.

Answer 2

As UITableViewCell's get recycled which is quite unpredictable.
So one approach is to maintain the state with key value pairs
that this NSDictionary and set images as per state changed in NSDictionary like
#{
"0":"EnableImage",
"1":"DisableImage",
"2":"DisableImage",
"3":"EnableImage",
}
so set image as per the above dictionary in cellForRowAtIndexPath.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
.... ....
You need set image as per state maintained in above dictionary
return cell;
}
And Remove below code
(void)awakeFromNib {
// Initialization code
[self.firstYesButton setImage:[UIImage imageNamed:#"yesRateDisable.png"] forState:UIControlStateNormal];
}
- (IBAction)firstYesAction:(id)sender {
[self.firstYesButton setImage:[UIImage imageNamed:#"yesRateEnable.png"] forState:UIControlStateNormal];
}