Removing subviews when bar button is tapped - ios

Question

I am trying to trigger adding two subviews when a Bar Button is tapped. But adding the subviews works just fine, but when I try removing the subviews, it doesn't work.
Here is the code I am implementing
-(IBAction)showPopover:(id)sender{
UIView *popoverView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
UIView *popoverViewBackground = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 1000)];
popoverView.alpha = 0.0;
popoverView.layer.cornerRadius = 2;
popoverView.layer.borderWidth = 0.1f;
popoverView.layer.backgroundColor = [UIColor whiteColor].CGColor;
popoverView.layer.masksToBounds = YES;
popoverViewBackground.layer.backgroundColor= [UIColor blackColor].CGColor;
if (popoverCount == 0) {
[self.view addSubview:popoverViewBackground];
[self.view addSubview:popoverView];
popoverCount = 1;
}else if (popoverCount ==1){
[popoverView removeFromSuperview];
[popoverViewBackground removeFromSuperview];
popoverCount = 0;
}
[popoverViewBackground setAlpha:0.5];
[popoverView setAlpha:1.0];
}

Answer 1

Problem is that you are creating new view every time you click the button so old view not removing put your code like thi, then it will work fine.I have tested it.
in .h file
#interface secondViewController : UIViewController
{
int popoverCount;
UIView *popoverView ;
UIView *popoverViewBackground;
}
in .m file
- (void)viewDidLoad
{
[super viewDidLoad];
popoverView = [[UIView alloc] initWithFrame:CGRectMake(0, -100, 320, 100)];
popoverViewBackground = [[UIView alloc] initWithFrame:CGRectMake(0, -100, 320, 100)];
popoverView.alpha = 0.0;
popoverView.layer.cornerRadius = 2;
popoverView.layer.borderWidth = 0.1f;
popoverView.layer.backgroundColor = [UIColor whiteColor].CGColor;
popoverView.layer.masksToBounds = YES;
popoverViewBackground.layer.backgroundColor= [UIColor blackColor].CGColor;
}
-(IBAction)showPopover:(id)sender {
if (popoverCount == 0) {
[self.view addSubview:popoverViewBackground];
[self.view addSubview:popoverView];
[UIView animateWithDuration:0.5
animations:^{
popoverView.frame = CGRectMake(0,0,320,100);
}
completion:^(BOOL finished){
;
}];
[UIView animateWithDuration:0.5
animations:^{
popoverViewBackground.frame = CGRectMake(0,0,320,100);
}
completion:^(BOOL finished){
;
}];
popoverCount = 1;
}else if (popoverCount ==1){
[UIView animateWithDuration:0.5
animations:^{
popoverView.frame = CGRectMake(0,-100,320,100);
}
completion:^(BOOL finished){
[popoverView removeFromSuperview];
}];
[UIView animateWithDuration:0.5
animations:^{
popoverViewBackground.frame = CGRectMake(0,-100,320,100);
}
completion:^(BOOL finished){
[popoverViewBackground removeFromSuperview];
}];
popoverCount = 0;
}
[popoverViewBackground setAlpha:0.5];
[popoverView setAlpha:1.0];
}

Answer 2

UIView *popoverView;
UIView *popoverViewBackground;
Declare popoverView and popoverViewBackground in .h file and allocate and initializes of these subview in when popoverCount is zero.
-(IBAction)showPopover:(id)sender{
if (popoverCount == 0) {
popoverView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
popoverViewBackground = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 1000)];
popoverView.alpha = 0.0;
popoverView.layer.cornerRadius = 2;
popoverView.layer.borderWidth = 0.1f;
popoverView.layer.backgroundColor = [UIColor whiteColor].CGColor;
popoverView.layer.masksToBounds = YES;
popoverViewBackground.layer.backgroundColor= [UIColor blackColor].CGColor;
[self.view addSubview:popoverViewBackground];
[self.view addSubview:popoverView];
popoverCount = 1;
}else if (popoverCount ==1){
[popoverView removeFromSuperview];
[popoverViewBackground removeFromSuperview];
popoverCount = 0;
}
[popoverViewBackground setAlpha:0.5];
[popoverView setAlpha:1.0];
}

Answer 3

At least 2 issues in your code:
Every time the method is involved, you are creating new instances of these sub-views
You are removing the newly created instances. That is, previous instances that were added still exist.
You should
save these sub-views in instance variables, so that you can refer to them and remove them correctly.
move the creation code inside the first if-block, so that you are not creating too many sub-views.

Answer 4

It is happening because you are applying addSubview and removeFromSuperview on different object.
When First time showPopover is called it create two object of UIView
with name popoverView and popoverViewBackground.
and add this to self.view.
Till now every thing fine but when this method call second time
New object of popoverView and popoverViewBackground created again and
You are trying to remove that new created object from self.view which is not there.
How to solve this:
There are two way to solve this:
1) Create this object in .h file so you can access it from anywhere.
2) create object in such way that it created only when method call first time.
Give this UIView tag and when you remove find this tag in UIView.subview
Way 1 is easy way 2 require some code but you can make it efficient in turm of memory.
All the best