UISwitch not reaction - ios

Question

This is probably simple. My UISwitch from my xib is connected to an IBOutlet "switch".
however when i create the viewController, i want to check if a variable is YES/NO, and the switch should be the correct value.
ViewController *vc = [[ViewController alloc] init];
if(variable ==YES){
[vc.switch setOn:YES];
}else{
[vc.switch setOn:NO];
}
however its always unchecked. What could i be doing wrong? i´ve double checked the connection to the IBOutlet

Answer 1

You aren't calling the correct method; UISwitch doesnt' have a setOn method. it has an on property and a senOn:animated: method.
either:
ViewController *vc = [[ViewController alloc] init];
vc.switch.on = variable
or:
ViewController *vc = [[ViewController alloc] init];
[vc.switch setOn:variable animated:YES];
Note, you are already checking against a BOOL, I've shown how to do it without the needless check.

Answer 2

This is the most common problem new developers have. Actually i had the same problem once. at that time i don't know the reason of happening this. i think now i am clear about such problems.
Let me give you some tips.
You should never access any UIView controls before presenting or pushing viewcontroller. you can access the UIView controls after presenting/pushing.
You can achieve this by setting the boolean value also. Create deafultSwitchStatus boolean property because its a boolean type this value will remain memory before viewDidLoad. and you can assign this status to your UISwitch object in viewDidLoad.
In short. UIView controls are not created/loaded before viewDidLoad method and viewDidLoad is called after preseting/pushing any controller. it means your controls are nil if you are accessing before presenting/pushing. those controls will not have any effect of your code because it will be overwritten.
Hope i explained right :)

Answer 3

You have created ViewController, but not presented it. So loadView was never called and yours .switch is nil.
try this:
ViewController *vc = [[[ViewController alloc] init] autorelease];
[self presentViewController:vc
animated:YES
completion:^(){
vc.switch.on = variable;
}];