UISwitch in each sectioned table row's accessoryView

Question

I am new to iOS coding, I looked around here in SO and tried several approaches to solve this, but nothing seems to work. I'm shure it's because of some silly mistake of mine :-)

I have a sectioned table, with about 25 rows in total, divided in 2 sections. There is a switch for each cell.accessoryView, i try to store the switch state, when it changes, in a NSArray, but logging the array content at that index weirdly returns 0 in any case. (The array is instantiated as a property (nonatomic, readwrite) of the TableViewController, and synthesized)

And obviously , when i scroll the table up and down, all the switches return in the default OFF state.

Thanks for any help!

- (void)viewDidLoad
{
[super viewDidLoad];
//countries dict and switch state array init..  
self.countries = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"countries" ofType:@"plist"]];
NSNumber *b = [NSNumber numberWithBool:NO];
for (int i=0; i<210; i++) {
    [statiSwitch addObject:b];
    NSLog(@"%d", [[statiSwitch objectAtIndex:i] integerValue]);
}

//tableview drawing..
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"CellWithSwitch";    
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

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

NSString *continent = [self tableView:tableView titleForHeaderInSection:indexPath.section];
NSString *country = [[self.countries valueForKey:continent] objectAtIndex:indexPath.row];

//Simple tag calculation...
NSInteger tagOb = indexPath.section * 100 + indexPath.row;

UISwitch *mySwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
[mySwitch addTarget:self action:@selector(switchChange:) forControlEvents:UIControlEventValueChanged];
mySwitch.tag = tagOb;
if ([statiSwitch count] > tagOb) {
    [mySwitch setOn:[[statiSwitch objectAtIndex:tagOb] boolValue] animated:NO];
     }

cell.textLabel.text = country;    
cell.accessoryView = mySwitch;

return cell;
}

And then the method called at switch status change:

- (void) switchChange:(UISwitch *)sender {
NSNumber *c = [NSNumber numberWithBool:sender.on];
[statiSwitch replaceObjectAtIndex:sender.tag withObject:c];

NSLog(@"switch tag is: %i and state is: %d", sender.tag, sender.on);
NSLog(@"switch states array value: %d", [[statiSwitch objectAtIndex:sender.tag] integerValue]);
}

Answer 1

I think you had omitted to initialize statiSwitch before adding objects to it.

In viewDidLoad before the for-loop, add this line

statiSwitch = [NSMutableArray array];

Answer 2

1. Set up a custom cell class.
2. Create a prototype cell in your storyboard, and place a switch in it.
3. Set the prototype cell to your custom class, and set a reuse identifier.
4. Connect the switch to an IBOutlet in your custom cell class. (Also set up @protocol and delegate if you want your cell to be able to communicate)
5. Now for the tricky/hackish part:

In -viewDidLoad:

    for (int i = 0; i < [self.cellDataArray count]; ++i) {
            CustomCell *cell;

    cell = [self.tableView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:nil];
    cell.delegate = self;
    [self.cellsArray addObject:cell];
}

1. In your cellForRowAtIndexPath, do the following:

   cell = self.cellsArray[indexPath.row]; // or .item if using a collectionView

2. Since the switch is connected to each cell, you need a method in your CustomCell class that will do something based on the switch, and perhaps send a call to the delegate class.

Answer 3

I used a simple int array to store the switches values, it appears to work better than a NSMutableArray made up of objects with switchTag and switchState properties, which is what i used to do before.

Here is the code:

- (void)viewDidLoad
{   
    //[here goes the code to retrieve my table data from a dictionary, getting sections and rows]

    //int array iniazialization, with zeros to have switches set at OFF at beginning

    for (int i = 0; i < 300; i++) {
    switchStates[i] = 0;
        }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    static NSString *CellIdentifier = @"Cella"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

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

//Cell drawing..

NSString *continent = [self tableView:tableView titleForHeaderInSection:indexPath.section];
NSString *country = [[self.countries valueForKey:continent] objectAtIndex:indexPath.row];
cell.textLabel.text = country;

//Calculate the tag to be assigned to the switches..

    switchTag = indexPath.section * 100 + indexPath.row
    UISwitch *mySwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
    [mySwitch addTarget:self action:@selector(switchChange:) forControlEvents:UIControlEventValueChanged];
    mySwitch.tag = switchTag;
    mySwitch.on = switchStates[switchTag];

    cell.accessoryView = mySwitch;

    return cell;

}

//switch change action..

- (void) switchChange:(UISwitch *)sender {
     switchStates[sender.tag] = sender.on;
}

Now i have "just" to store those switch values in core data.. see you here for my upcoming questions :-)