There are a number of apps in the App Store that launch with a set of closed doors, these are then opened to present the actual UI underneath it.

I had to create this effect for an app I wrote for a client http://itunes.com/apps/jkmuaythai

I’d assumed when I started that this would be a relatively simple task, just take the initial default image, cut it in half and a simple bit of animation would move them out of the way. What I hadn’t counted on is getting the orientation of the device from launch is not straightforward. The trick is to remember that the first view that is loaded will always assume it’s in Portrait mode, the view is then informed via the willRotate method that in fact the orientation is different and you can then handle this appropriately. The second trick is knowing that the willRotate takes a little bit of time to fire, so it’s now a simple case of delaying the call to the method that handles the animation.

The viewWillAppear method loads the images assuming that the view is in portrait and sets up a timer to call the openDoors method

-(void)viewWillAppear:(BOOL)animated {
    //All apps start in portrait mode, with the home button at the bottom,
    //If the device is being held with the home button in any other location then a
    //willRotate is fired!
    isPortrait = YES;
    doorsClosed = YES;

    //We assume we are in portrait mode until told otherwise
    self.leftDoor.image = [UIImage imageNamed:@"DoorLeftiPadPortrait.png"];
    self.rightDoor.image = [UIImage imageNamed:@"DoorRightiPadPortrait.png"];
    self.backgroundSplash.image = [UIImage imageNamed:@"SlideBackgroundiPadPortrait.png"];

    //Add a delay to the open doors sequence, this allows the OS to determine
    //the correct orientaion and fire the all important willRotate

    [NSTimer scheduledTimerWithTimeInterval: 3.5
                                     target: self
                                   selector: @selector(openDoors)
                                   userInfo: nil
                                    repeats: NO];
}

The willRotate method then ensures that the correct image is loaded

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return YES;
}

-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
    isPortrait = UIDeviceOrientationIsPortrait(toInterfaceOrientation);
    if (!isPortrait) {
        //If the doors haven't already been opened then change them to the landscape ones
        if (doorsClosed) {
            self.leftDoor.image = [UIImage imageNamed:@"DoorLeftiPadLandscape.png"];
            self.rightDoor.image = [UIImage imageNamed:@"DoorRightiPadLandscape.png"];
        }
        self.backgroundSplash.image = [UIImage imageNamed:@"SlideBackgroundiPadLandscape.png"];
    } else {
        self.backgroundSplash.image = [UIImage imageNamed:@"SlideBackgroundiPadPortrait.png"];
    }
}

The openDoors method then just works out how far to move the images and kicks of the animation, I’ve included the old UIView beginAnimation and the Blocks way

-(void)openDoors {
    //Determine how far the doors need to move for them to disappear from view
    float adjust = (CGRectGetWidth(self.view.frame) > CGRectGetHeight(self.view.frame)) ? CGRectGetWidth(self.view.frame) : CGRectGetHeight(self.view.frame);
    //Retrieve the original frame and then adjust the X position accordingly
    CGRect leftFrame = self.leftDoor.frame;
    CGRect rightFrame = self.rightDoor.frame;;

    leftFrame.origin.x = -adjust;
    rightFrame.origin.x += adjust;

//Old School Animation

//Set up the animation, change the frames and commit it
//	[UIView beginAnimations:@"swipe" context:nil];
//	[UIView setAnimationDuration:1.2];
//	[UIView setAnimationDelay:0.0];
//	[UIView setAnimationDelegate:self];
//
//      self.leftDoor.frame = leftFrame;
//	self.rightDoor.frame = rightFrame;
//
//	[UIView commitAnimations];

//Blocks
    [UIView animateWithDuration:1.2
                     animations:^{
                        self.leftDoor.frame = leftFrame;
                        self.rightDoor.frame = rightFrame;
                     }
    ];

    doorsClosed = NO;
}

Note this effect only works if the app is launching for the first time, i.e. not from the background.

I’ve put together a sample project that puts this all into practice

https://github.com/Flexicoder/OpenDoorsDemo

Hope you find this useful, or if you have a better way of creating the same effect please let me know

• What are the target platforms, iPhone, iPad, Android, Windows Mobile?
• If iPhone do you want a universal version, i.e. the same app runs on iPhone and iPad (thanks @ithain)
• Whats the target audience?
• Do you have an idea of how you want the app to flow?
• Are there existing apps out there that do something similar, if there are what are they and what will make this one different?
• Are there existing apps that you like the style of or the way they work?
• Will you apply for your own developers licences so that the app is submitted under your name?
• Will the app be free, sold for a one off fee, have in-app purchases or have subscriptions?
• Who will supply the artwork?
• Does the app need to be location aware?
• Ideas of timescale for release? (thanks @MrAntix)
• Are there any hosting requirements? (thanks @MrAntix)
• Third party services integration requirements? (thanks @MrAntix)
• Any social media integration?

And if the app contains dynamic data the following are also important questions…

• How will the app access the data?
• Have the web services that supply the information been designed/written?
• Would you require a content management system to update information contained in the app?
• If its a Corporate app, what back end data do you need to access and synchronise (thanks @ithain)

Obviously the answers to these questions are likely to lead to more specific questions, but it helps with the thought process involved with what might be required

I would be really interested to know if there are any other questions you ask that I’ve not included?

Turns out that as it creates the underlying png for some reason it saves it in a flipped format, therefore you need to load the png into your favourite graphics package and flip it vertically before using it in your project

See what I do

http://webtreats.mysitemyway.com/

At the moment you have to specify the names using the CFBundleIconFiles

This is also a useful link to the Apple site that explains what icons are need for what device

Multi-tasking can be great, but it has added some complexity to programming on the iPhone. For many apps there really is no advantage. For instance, does the “That’s What She Said” button really need to stay in memory?

It’s some added complexity that programmers don’t need.. some of the more complex memory intensive apps will just exit anyways, and programming the app to suspend can be a highly complicated task.

Fortunately there is a simple way to make your iOS 4 apps terminate for real when the user taps the home button.

This is a simple process:

Open your info.plist file
Add The Key UIApplicationExitsOnSuspend
Set the new key to YES
Now your applicationwillterminate: method will be run when the user taps the home key, and your app will exit for real.

See what I do

Upload image to simulator

Clicking save will then include your image.