How to retrieve UISwitch state in each of my UITableView cells?

问题

I have a UISwitch set as the accessoryView in each of my TableView cells.

If I press my Confirm button, I want to save the state of each UISwitch with NSUserDefaults. Then when I leave and go back to that View Controller, I should be able to load those saved states which will be different for each cell (either on or off, as shown in image).

I'm almost there but I guess I am not sure how to save/load with the right indexPath.row so it's not working correctly. Right now it is just saving/loading one BOOL value only, so if I save one cell with the switch ON, then all of them will be ON, and vice versa.

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:YES];

    BOOL menuSwitchState = [[NSUserDefaults standardUserDefaults] boolForKey:@"menuItemSwitch"];
    NSLog(@"Menu Switch State is: %@", menuSwitchState ? @"Yes": @"No");
    [self.switchView setOn:menuSwitchState animated:YES];

}

UISwitch code in my cellForRowAtIndexPath:

   // Add a UISwitch to the accessory view.
    self.switchView = [[UISwitch alloc] initWithFrame:CGRectZero];
    cell.accessoryView = self.switchView;
    self.switchView.tag = indexPath.row;
    self.switchView.on = [[NSUserDefaults standardUserDefaults] boolForKey:@"menuItemSwitch"];
    [self.switchView addTarget:self action:@selector(switchChanged:) forControlEvents:UIControlEventValueChanged];

Switch action method which sets a BOOL:

- (void) switchChanged:(id)sender {
    UISwitch *switchControl = sender;
    NSLog(@"The switch's tag number is %ld", (long)switchControl.tag);
//    NSLog(@"The switch is %@", switchControl.on ? @"ON" : @"OFF" );


    if ([sender isOn])
    {
        self.switchIsOn = YES;
        NSLog(@"THE SWITCH IS ON");
    }
    else
    {
        self.switchIsOn = NO;
        NSLog(@"THE SWITCH IS OFF");
    }
}

Confirm button that should save the state of the switch:

#pragma mark - UIBUTTONS
- (IBAction)onConfirmMenuButtonPressed:(id)sender
{
    [self performSegueWithIdentifier:@"segueMenuToGettingStarted" sender:self];


    //TODO: Save state of Switch.
    if (self.switchIsOn == YES)
    {
        [[NSUserDefaults standardUserDefaults] setBool:self.switchView.on forKey:@"menuItemSwitch"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
    else
    {
        NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
        [ud setBool:NO forKey:@"menuItemSwitch"];
    }



}

回答1:

You save that value just like any other value you use in a table view -- in an array that's your data source. Given what you show in your image, your data source should be an array of dictionaries with keys for the menu item, price, and switch state. In cellForRowAtIndexPath, you would set the state of the switch based on the value ( a BOOL) in your array.

回答2:

in your code, you just set one NSUserDefault value for the all items(now, looks like three), I think you must separate each kind of item, it means you must have the count of NSUserDefault same as the count of UISwitch, In UIViewController, you can hold the NSUserDefault values in an Array, when you change the switch, you changed the cell data, when you leave the ViewController, save the Array's values. Enter the ViewController, update the Array.

来源：https://stackoverflow.com/questions/29595757/how-to-retrieve-uiswitch-state-in-each-of-my-uitableview-cells

标签

ios

objective-c

uitableview

nsuserdefaults

uiswitch