How to properly implement multiple subview operations in IPAD

I am creating an iPAD app. I have got a MAIN VIEW controller which covers the whole screen. And I have another class DROP-DOWN Class which i will be using to mimic the functionality of a drop-down as in Windows OS components. For that I am using a simple button, a scroll view开发者_JAVA百科 and a few labels. I instantiate an object of that class and use it in my MAIN VIEW controller. To create the effect of a drop down, I alter the instance's views frame on the touch up of the button in toggle mode.(Click once, frame increased, click again frame decreased).

The creation part was fine, and the function to toggle to worked fine when implemented on a single instance of the DROP DOWN object.

But the problem comes when I instantiate these objects thru a for loop. The views seem to just vanish on button click.

Here is the code within the dropdowns.

- (void)viewDidLoad {
[super viewDidLoad];

self.view.backgroundColor = [UIColor redColor];

UIScrollView *scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(10,54,100,50)];

scrollView.contentSize = CGSizeMake(50, 100);

for (int i = 0; i< 10; i++)
{
    UILabel *newLable = [[UILabel alloc]initWithFrame:CGRectMake(0, 10*i, 100, 10)];
    [newLable setFont:[UIFont boldSystemFontOfSize:10]];
    newLable.text = [NSString stringWithFormat:@"Testing %i",i];
    [scrollView addSubview:newLable];
}

scrollView.backgroundColor = [UIColor greenColor];
[self.view addSubview:scrollView];
}

-(IBAction)btnClicked:(id)sender
{
if (!isOpen) {

    oldRect = self.view.frame;

    CGRect newFrame = self.view.frame;

    newFrame.size = CGSizeMake(190, 200);
    NSLog(@"New Frame - %f,%f,%f,%f",self.view.frame.origin.x,self.view.frame.origin.y,self.view.frame.size.height,self.view.frame.size.width);
    self.view.frame = newFrame;
}
else {
    self.view.frame = oldRect;
    NSLog(@"Old Frame - %f,%f,%f,%f",self.view.frame.origin.x,self.view.frame.origin.y,self.view.frame.size.height,self.view.frame.size.width);

}
isOpen = !isOpen;
} 

And here is how this is called from the main view.

- (void)viewDidLoad {
[super viewDidLoad];


[self performSelector:@selector(drawTheFilters)];



}

-(void)drawTheFilters
{
for (int i = 0; i<5 ; i++) {

    DropDownView *dropView = [[DropDownView alloc]initWithNibName:@"DropDownView" bundle:[NSBundle mainBundle]];

    CGRect newFrame = dropView.view.frame;

    newFrame.origin = CGPointMake(200*i, 200);

    dropView.view.frame = newFrame;

    [self.view addSubview:dropView.view];

    NSLog(@"Frame %i, %f,%f,%f,%f",i,dropView.view.frame.origin.x,dropView.view.frame.origin.y,dropView.view.frame.size.height,dropView.view.frame.size.width);
}

}