Save checkbox values - ios

Question

As many others here I am new to Xcode and would like to ask a basic question. When checking a box and leaving Xcode, this value is not saved (unchecked box) when I reopen the Xcode project.
I have seen different discussions here: e.g. how to save a checkbox value check/uncheck to NSUserDefaults but it is not working in my code. Do you have a hint where the problem is?
In my .h I have created an instance of a BOOL (called “checked“) and a UIButton is connected both as an IBAction and as an IBOutlet.
- (void)viewDidLoad{
checked = NO;
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"Negative"];
BOOL checked = [[NSUserDefaults standardUserDefaults] boolForKey:#"Negative"];
[[NSUserDefaults standardUserDefaults] synchronize];
[super viewDidLoad];
NSUserDefaults *defaults70 = [NSUserDefaults standardUserDefaults];
checked = [defaults70 boolForKey: #"boxIsChecked70"];
[self checkTheBox];
[self updateLabels];}
- (IBAction)CheckCOUTCheckButton:(id)sender {
NSUserDefaults *defaults70 = [NSUserDefaults standardUserDefaults];
if (! checked) {
[_CheckBoxCOUTButton setImage:[UIImage imageNamed:#"Checkboxcheckedimage.png"] forState:UIControlStateNormal];
checked = YES;
[defaults70 setBool:checked forKey:#"boxIsChecked70"];}
else if (checked) {
[_CheckBoxCOUTButton setImage:[UIImage imageNamed:#"Checkboxuncheckedimage.png"] forState:UIControlStateNormal];
checked = NO;
[defaults70 setBool:checked forKey:#"boxIsChecked70"];}
[defaults70 synchronize];}
- (void) checkTheBox {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (! checked) {
[_CheckBoxCOUTButton setImage:[UIImage imageNamed:#"Checkboxuncheckedimage.png"] forState:UIControlStateNormal];
}
else if (checked) {
[_CheckBoxCOUTButton setImage:[UIImage imageNamed:#"Checkboxcheckedimage.png"] forState:UIControlStateNormal];
}
- (IBAction)ClearAllFields:(id)sender {
[_CheckBoxCOUTButton setImage:[UIImage imageNamed:#"Checkboxuncheckedimage.png"] forState:UIControlStateNormal];
checked = NO;}

Answer 1

Your problem is an problem of scope. You are defining a second variable called checked and confusing which one you're setting.
- (void)viewDidLoad{
checked = NO;
in this line you are setting the property - ie the self.checked value to NO.
BOOL checked = [[NSUserDefaults standardUserDefaults] boolForKey:#"Negative"];
[[NSUserDefaults standardUserDefaults] synchronize];
in this line however you are declaring a NEW local variable that will only exist within viewDidLoad.
try removing the BOOL before it. When viewDidLoad returns this local variable will go out of scope and disappear.
checked = [[NSUserDefaults standardUserDefaults] boolForKey:#"Negative"];
[[NSUserDefaults standardUserDefaults] synchronize];
so later on when you set the checkbox as part of checkTheBox you're reading the property, not your local variable that you set.
let me know if this isn't clear.

Answer 2

I am not sure if this is your only problem, but in your viewDidLoad, you are basically setting a value before you're reading it:
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"Negative"];
BOOL checked = [[NSUserDefaults standardUserDefaults] boolForKey:#"Negative"];
You probably want to do this:
BOOL checked = [[NSUserDefaults standardUserDefaults] boolForKey:#"Negative"];