====== SHSwipeEvent ======
---- dataentry extension ----
type            : extension
author_mail     : shilo86@gmail.com Shilo White
description     : A simple swipe event.
lastupdate_dt   : 2011-03-22
compatible      : v1.X
depends         : 
tags            : swipe, event, swipeevent
homepage_url    : https://gist.github.com/882536
download_url    : https://gist.github.com/gists/882536/download
sample_url      : http://shilo.coarsemode.com/sparrow/extensions/shswipeevent/SnakeSample.zip
min iOS version : 3.2
----

===== Description =====
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.

===== Sample =====
[[http://shilo.coarsemode.com/sparrow/extensions/shswipeevent/SnakeSample.zip|{{http://shilo.coarsemode.com/sparrow/extensions/shswipeevent/SnakeScreenshot.png}}]]
  * Project: [[http://shilo.coarsemode.com/sparrow/extensions/shswipeevent/SnakeSample.zip|Snake Game]]
  * Screenshot: [[http://shilo.coarsemode.com/sparrow/extensions/shswipeevent/SnakeScreenshot.png|SnakeScreenshot.png]]
  * Recording: [[http://shilo.coarsemode.com/sparrow/extensions/shswipeevent/SnakeRecording.mov|SnakeRecording.mov]]

===== Example =====
<code objc>
@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
</code>

===== Instructions =====
==== To add into your Sparrow project ====
  - Download the source files here: [[https://gist.github.com/gists/882536/download]]
  - Open your desired Sparrow project
  - Drag and drop the files into the "Groups & Files" pane
  - Open "Game.h"
  - Include the extension: <code objc>#include "SHSwipeEvent.h"</code>
  - Save "Game.h"

==== To add directly into Sparrow source ====
  - Download the source files here: [[https://gist.github.com/gists/882536/download]]
  - Save the files into Sparrow's "/Classes/" directory
    * Example: "/sparrow/src/Classes/"
  - Navigate back one directory and open "Sparrow.xcodeproj"
    * Example: "/sparrow/src/Sparrow.xcodeproj"
  - Inside the "Groups & Files" pane, locate the "Events" group folder
    * Example: "Sparrow -> Classes -> Events"
  - Right click the "Display" group folder and click "Add -> Existing Files.."
  - Navigate into the "/Classes/" directory and select "SHSwipeEvent.h" and "SHSwipeEvent.m", then click "add"
  - On the next window, leave all options as default and click "add"
  - In the "Groups & Files" pane, Open "Sparrow.h"
    * Example "Sparrow -> Classes -> Sparrow.h"
  - At the bottom of the file, add: <code objc>#import "SHSwipeEvent.h"</code>
  - Save "Sparrow.h"
  - Close "Sparrow.xcodeproj"

===== Troubleshooting =====
==== Why is it not recognizing swipes? ====
Make sure you add this line before listening for a SPSwipeEvent:
<code objc>[self.stage startSwipeRecognizer];</code>

==== Why is it not recognizing the correct swipe direction? ====
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).

==== Why am I getting a runtime error/crash? ====
If you are encountering this runtime error:
<code objc>*** Terminating app due to uncaught exception 'NativeViewDoesNotExist', reason: 'nativeView not linked to stage yet.'</code>

Inside your ApplicationDelegate, I suggest you link your Game class to sparrowView (SPView) BEFORE initializing your Game class, like so:
<code objc>
- (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;
}
</code>

//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.

===== Source Code =====
%gist(882536)%

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

===== Todo =====
  * Add continuous swipe option