SHSwipeEvent class will allow you to easily listen to swipe events inside Sparrow, it also contains extra methods to get the location and direction based on spaces that inherit SPDisplayObject.

• Project: Snake Game
• Screenshot: SnakeScreenshot.png
• Recording: SnakeRecording.mov

@implementation Game
- (id)initWithWidth:(float)width height:(float)height {
        if (self = [super initWithWidth:width height:height]) {
	        //set a container sprite in landscape
		mContainer = [SPSprite sprite];
		mContainer.rotation = SP_D2R(90);
		mContainer.x = 320;
		[self addChild:mContainer];
 
		//start swipe recognizer
		[self.stage startSwipeRecognizer];
 
		//add a swipe event listener
		[self addEventListener:@selector(onSwipe:) atObject:self forType:SH_EVENT_TYPE_SWIPE];
        }
        return self;
}
 
- (void)onSwipe:(SHSwipeEvent *)event {
        //get the global coordinates from the start of the swipe
	SPPoint *globalLocation = event.location;
 
	//get the local coordinates based on mContainer
	SPPoint *localLocation = [event locationInSpace:mContainer];
 
	//get the global swipe direction
	SHSwipeDirection globalDirection = event.direction;
 
	//get the local swipe direction based on mContainer
	SHSwipeDirection localDirection = [event directionInSpace:mContainer];
 
	//check the local swipe direction
	if (localDirection == SHSwipeDirectionUp) {
		NSLog(@"swiped up");
	} else if (localDirection == SHSwipeDirectionDown) {
		NSLog(@"swiped down");
	} else if (localDirection == SHSwipeDirectionLeft) {
		NSLog(@"swiped left");
	} else if (localDirection == SHSwipeDirectionRight) {
		NSLog(@"swiped right");
	}
}
 
- (void)dealloc {
	//stop and remove swipe recognizer
	[self.stage stopSwipeRecognizer];
 
	[self removeChild:mContainer];
	[super dealloc];
}
@end

1. Download the source files here: https://gist.github.com/gists/882536/download
2. Open your desired Sparrow project
3. Drag and drop the files into the “Groups & Files” pane
4. Open “Game.h”
5. Include the extension:

   #include "SHSwipeEvent.h"

6. Save “Game.h”

1. Download the source files here: https://gist.github.com/gists/882536/download
2. Save the files into Sparrow's “/Classes/” directory
   • Example: “/sparrow/src/Classes/”
3. Navigate back one directory and open “Sparrow.xcodeproj”
   • Example: “/sparrow/src/Sparrow.xcodeproj”
4. Inside the “Groups & Files” pane, locate the “Events” group folder
   • Example: “Sparrow → Classes → Events”
5. Right click the “Display” group folder and click “Add → Existing Files..”
6. Navigate into the “/Classes/” directory and select “SHSwipeEvent.h” and “SHSwipeEvent.m”, then click “add”
7. On the next window, leave all options as default and click “add”
8. In the “Groups & Files” pane, Open “Sparrow.h”
   • Example “Sparrow → Classes → Sparrow.h”
9. At the bottom of the file, add:

   #import "SHSwipeEvent.h"

10. Save “Sparrow.h”
11. Close “Sparrow.xcodeproj”

Make sure you add this line before listening for a SPSwipeEvent:

[self.stage startSwipeRecognizer];

if you are using “directionInSpace:” method with a SPDisplayObject that has a rotation that is not in increments of 90 degrees, you won't always get an accurate direction. This is because UISwipeGestureRecognizer does not hold the exactly angle/degree of the direction. Again, this is only if you use degrees that are not: (-180, -90, 0, 90, 180, 270, ect).

If you are encountering this runtime error:

*** Terminating app due to uncaught exception 'NativeViewDoesNotExist', reason: 'nativeView not linked to stage yet.'

Inside your ApplicationDelegate, I suggest you link your Game class to sparrowView (SPView) BEFORE initializing your Game class, like so:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    SP_CREATE_POOL(pool);
 
    [SPStage setSupportHighResolutions:YES];
    [SPAudioEngine start];
 
    Game *game = [Game alloc];
    sparrowView.stage = game;
    game = [game init];
    [game release];
 
    [window makeKeyAndVisible];
    [sparrowView start];
 
    SP_RELEASE_POOL(pool);
 
    return YES;
}

Warning: Although this method works fine in this situation, it might not be safe to get an instance of other Apple/Sparrow classes before initialization. The class might release and initialize a new instance of itself in the “init” method, which would make the old instance invalid.

You could also call “startSwipeRecognizer:” method after the initialization of your Game class to ensure that SPStage is linked to SPView.

• 2011-03-10: First version
• 2011-06-21: Events now dispatch to hit display objects and bubble correctly. (Thank you odie)

• Add continuous swipe option