Question

Ok, so bear with me: as this is an Objective-C related question, there’s obviously a lot of code and subclassing. So here’s my issue. Right now, I’ve got an iPad app that programmatically creates a button and two colored UIViews. These colored UIViews are controlled by SubViewControllers, and the entire thing is in a UIView controlled by a MainViewController. (i.e. MainViewController = [UIButton, SubViewController, SubViewController])

Now, all of this happens as it should, and I end up with what I expect (below):

However, when I click the button, and the console shows “flipSubView1”, nothing happens. No modal view gets shown, and no errors occur. Just nothing. What I expect is that either subView1 or the entire view will flip horizontally and show subView3. Is there some code that I’m missing that would cause that to happen / is there some bug that I’m overlooking?

viewtoolsAppDelegate.m

@implementation viewtoolsAppDelegate

@synthesize window = _window;
@synthesize mvc;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    mvc = [[MainViewController alloc] initWithFrame:self.window.frame];
    [self.window addSubview:mvc.theView];
    [self.window makeKeyAndVisible];

    return YES;
}

MainViewController.m

@implementation MainViewController

@synthesize theView;
@synthesize subView1, subView2, subView3;

- (id)initWithFrame:(CGRect) frame
{
    theView = [[UIView alloc] initWithFrame:frame];
    CGRect sV1Rect = CGRectMake(frame.origin.x+44, frame.origin.y, frame.size.width-44, frame.size.height/2);
    CGRect sV2Rect = CGRectMake(frame.origin.x+44, frame.origin.y+frame.size.height/2, frame.size.width-44, frame.size.height/2);
    subView1 = [[SubViewController alloc] initWithFrame:sV1Rect andColor:[UIColor blueColor]];
    subView2 = [[SubViewController alloc] initWithFrame:sV2Rect andColor:[UIColor greenColor]];
    subView3 = [[SubViewController alloc] initWithFrame:sV1Rect andColor:[UIColor redColor]];
    [theView addSubview:subView1.theView];
    [theView addSubview:subView2.theView];

    UIButton *aButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [aButton addTarget:self action:@selector(flipSubView1:) forControlEvents:(UIControlEvents)UIControlEventTouchDown];
    [aButton setFrame:CGRectMake(0, 0, 44, frame.size.height)];
    [theView addSubview:aButton];

    return self;
}

- (void)flipSubView1:(id) sender
{
    NSLog(@"flipSubView1");
    [subView3 setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];
    [subView1 presentModalViewController:subView3 animated:YES];
}

SubViewController.m

@implementation SubViewController

@synthesize theView;

- (id)initWithFrame:(CGRect)frame andColor:(UIColor *)color
{
    theView = [[UIView alloc] initWithFrame:frame];
    theView.backgroundColor = color;
    return self;
}

TLDR: modal view not working. should see flip. don’t.

Answer 1

It doesn’t look like you’re setting the ‘view’ property of the MainViewController anywhere, just ‘theView’. The controllers view delegate must be connected to the root view it displays for it to work properly. You’ll need to correct that on the Sub View Controller impl as well. If you want all the plumbing that framework classes bring, you have to set things up the way they expect.

Also, you’re calling presentModalViewController on one of the sub view controllers; change that to call [self presentModalViewController:…], since the MainViewController is the one which will ‘own’ the modal view.

I think if you fix those points, you’ll find -presentModalViewController will work.