Checking if the UIPickerView is shown or hidden? The *if* conditions? - objective-c

Question

I have a little problem with my UIPickerView animation.
I did set up the animation so when I click a button the UIPickerView will slide up and after another click it will slide down. But I hit the problem on if. I tried to set up a new settings bool and set it's value after each animation, so the if was just checking for the bool. I'm not sure if I did explained it well, but maybe you get the idea from the code.
But unfortunately it's not working... Any ideas?
- (void)viewDidLoad
{
[super viewDidLoad];
settings = [NSUserDefaults standardUserDefaults];
[settings setBool:NO forKey:#"pickerShown"];
[settings synchronize];
}
- (IBAction)showPicker:(id)sender {
CGRect rect = countryPicker.frame;
CGPoint origin = CGPointMake(0, 510); // Some off-screen y-offset here.
rect.origin = origin;
countryPicker.frame = rect;
if ([settings boolForKey:#"pickerShown"] == YES) {
// Perform transform to slide it off the screen.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.5];
countryPicker.transform = CGAffineTransformMakeTranslation(0, -0); // Offset.
[UIView commitAnimations];
[settings setBool:NO forKey:#"pickerShown"];
[settings synchronize];
} else if ([settings boolForKey:#"pickerShown"] == NO) {
// Perform transform to slide it onto the screen.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.5];
countryPicker.transform = CGAffineTransformMakeTranslation(0, -266); // Offset.
[UIView commitAnimations];
[settings setBool:YES forKey:#"pickerShown"];
[settings synchronize];
}
}
EDIT:
Just found the solution...
If anyone's interested - here it is:
The h. file:
.
.
.
{
BOOL pickerShown;
}
.
.
.
The .m file:
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect rect = countryPicker.frame;
CGPoint origin = CGPointMake(0, 510); // Some off-screen y-offset here.
rect.origin = origin;
countryPicker.frame = rect;
pickerShown = NO;
}
- (IBAction)showPicker:(id)sender {
if (pickerShown == NO) {
// Perform transform to slide it onto the screen.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1];
//[UIView setAnimationDidStopSelector:#selector(hidePicker)];
countryPicker.transform = CGAffineTransformMakeTranslation(0, 0); // Offset.
[UIView commitAnimations];
[self performSelector:#selector(hidePicker) withObject:nil afterDelay:1];
} else if (pickerShown == YES) {
//countryPicker.hidden = NO;
// Perform transform to slide it onto the screen.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1];
countryPicker.transform = CGAffineTransformMakeTranslation(0, -266); // Offset.
[UIView commitAnimations];
countryPicker.hidden = NO;
}
}

Answer 1

If a view is visible on screen, it's window property will be non-nil.

Answer 2

Just found the solution... If anyone's interested - here it is:
The h. file:
.
.
.
{
BOOL pickerShown;
}
.
.
.
The .m file:
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect rect = countryPicker.frame;
CGPoint origin = CGPointMake(0, 510); // Some off-screen y-offset here.
rect.origin = origin;
countryPicker.frame = rect;
pickerShown = NO;
}
- (IBAction)showPicker:(id)sender {
if (pickerShown == NO) {
// Perform transform to slide it onto the screen.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1];
//[UIView setAnimationDidStopSelector:#selector(hidePicker)];
countryPicker.transform = CGAffineTransformMakeTranslation(0, 0); // Offset.
[UIView commitAnimations];
[self performSelector:#selector(hidePicker) withObject:nil afterDelay:1];
} else if (pickerShown == YES) {
//countryPicker.hidden = NO;
// Perform transform to slide it onto the screen.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1];
countryPicker.transform = CGAffineTransformMakeTranslation(0, -266); // Offset.
[UIView commitAnimations];
countryPicker.hidden = NO;
}
}

Answer 3

You can check it with:
self.countryPicker.superview
If picker is hidden then superview will be nil. Otherwise it will be containing view.

Answer 4

If all you want is the basic effect of displaying the picker view, then removing it again there is an easier way.
pseudocode:
//do any picker initialization here
if(!pickerIsShowing)
[self.view addSubview:yourPickerView];
else
[self.yourPickerView removeFromSuperView];