Sorry, just to be clear, you want your second view controller to have a button that when tapped, adds your third view controller taking up half the screen at the bottom?
If this is the case then you can do this with the new view controller containers in iOS5.
Ok, so you have three view controllers. For the sake of this lets say your class are called FirstViewController, SecondViewController and ThirdViewController.
I assume from what you say that you already have you instance of FirstViewController with a button, that moves you on to an instance of SecondViewController, and that the issue is then getting SecondViewController to add an instance of ThirdViewController to the bottom half of the screen when a button is pressed.
The .m file for SecondViewController will need to do something like this:
#import "ThirdViewController.h"
@interface SecondViewController ()
@property (retain) ThirdViewController *thirdViewConroller;
- (void)buttonTap;
@end
@implementation SecondViewController
@synthesize thirdViewConroller = _thirdViewConroller;
- (void)dealloc {
self.thirdViewConroller = nil;
[super dealloc];
}
- (void)loadView {
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.titleLabel.text = @"Show third controller";
[button addTarget:self action:@selector(buttonTap) forControlEvents:UIControlEventTouchUpInside];
button.frame = // Some CGRect of where you want the button to be
[self.view addSubview:button];
}
- (void)buttonTap {
// When the button is tapped, create an instance of your ThirdViewController and add it
self.thirdViewConroller = [[ThirdViewController alloc] initWithFrame:/* Some CGRect where you want the controller to be */ ];
[self.thirdViewConroller willMoveToParentViewController:self];
[self addChildViewController:self.thirdViewConroller];
[self.thirdViewConroller didMoveToParentViewController:self];
}
@end
This should give you a button on your second controller, that will create and add you third controller. Make sure yo us till have all the standard methods that you had before, this should be in addition to what you have.
In your interface for ThirdViewController:
@interface ThirdViewController : UIViewController <NSObject>
- (id)initWithFrame:(CGRect)frame;
@end
Then in the implementation of your ThirdViewController:
- (id)initWithFrame:(CGRect)frame {
self = [super initWithNibName:nil bundle:nil];
if (self) {
self.view.frame = frame;
// Do your init stuff here
}
return self;
}
It should then handle adding the views and such forth.
Make sure your thirdViewController class has a valid initWithFrame: initialiser method.
This should do the trick, if you need any further help let me know :)