How to Show and Hide UIPickerView like iOS Keyboard? - ios

Question

I have this code to hide UIPickerView by default:
- (void)viewDidLoad
{
[super viewDidLoad];
[_memberList setAlpha:0];
}
and this code to show UIPickerView when a button tapped :
- (IBAction)buttonChooseMember {
[UIView animateWithDuration:0.6 delay:0. options:UIViewAnimationOptionCurveEaseInOut animations:^{
[_memberList setAlpha:1];
} completion:nil];
}
and the last thing is this, to hide keyboard when user tap anywhere :
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
for (UIView * txt in self.view.subviews){
if ([txt isKindOfClass:[UITextField class]]) {
[txt resignFirstResponder];
}else if ([txt isKindOfClass:[UIPickerView class]]) {
[UIView animateWithDuration:0.6 delay:0. options:UIViewAnimationOptionCurveEaseInOut animations:^{
[_registerMLMList setAlpha:0];
} completion:nil];
}
}
}
but all of this just give me 'appear' animation, because it's only changing Alpha value from 0 to 1 (and vice versa). not slide-up or slide-down just like iOS keyboard.
I tried to use this animation below to have iOS keyboard look and feel on my UIPickerView :
- (IBAction)hidePicker {
UIPickerView *pickerView = [[UIPickerView alloc] init]; // default frame is set
float pvHeight = pickerView.frame.size.height;
float y = _screen.bounds.size.height - (pvHeight * -2); // the root view of view controller
[UIView animateWithDuration:0.5f delay:0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
self.picker.frame = CGRectMake(0 , y, pickerView.frame.size.width, pvHeight);
} completion:nil];
}
- (IBAction)showPicker {
UIPickerView *pickerView = [[UIPickerView alloc] init]; // default frame is set
float pvHeight = pickerView.frame.size.height;
float y = _screen.bounds.size.height - (pvHeight); // the root view of view controller
[UIView animateWithDuration:0.5f delay:0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
self.picker.frame = CGRectMake(0 , y, pickerView.frame.size.width, pvHeight);
} completion:nil];
}
I like this animation, it looks like iOS keyboard animation, but the problem with this animation is... when my app is loaded, the UIPickerView is already shows up. how to hide it when it loads up for the first time?
thank you.

Answer 1

All UIResponder objects have an inputView property. The inputView of a UIResponder is the view that will be shown in place of the keyboard when the responder becomes the first responder.
So if you want a UIPickerView to show up instead of the keyboard, you could simply do it by making your UIResponder (like a UITextField) have a UIPickerView as its inputView.
(As a caveat: you probably won't want a bare UIPickerView as the inputView, because you also need to account for when the keyboard would change size, like when you rotate. But this is the general idea.)

Answer 2

In viewDidLoad take one boolean variable and set it's value as TRUE and also set the UIPickerView's frame so that UIPickerView is invisible for first time.Based on the boolean value handle the frame animations to show or hide the picker view.

Answer 3

hidepicker and showpicker method idea is good, and the problem of "UIPicker is visible when the app is loaded" can be overcome by just setting the frame of UIPickerView while initiating it to the position such that it should not be visible...after that you can call the showpicker method to show the picker view.