How do I present UIViewController from SKscene with social framework? - ios7

Question

I am making a game like Flappy Bird. How do I present a UIViewController from SKScene?
First of all, I tell my environments
Mac OS X 10.9
Xcode 5.0.2
Sprite Kit(framework), social.framework(framework) are added in my project
My goal is to display a "Share" button upon Game Over. Tapping the share button image should present a SLComposeViewController (Twitter Share). The contents of the scene should not change.
I'd like to solve bellow issue and change display from GameOverScene to tweetSheet(display)
composed with social.framework.
The issue
[self presentViewController:tweetSheet animated:YES completion:nil];
//Error:No visible #interface for 'GameOverScene' declares the selector "presentViewController":animated:completion:
My coding files are below(I extracted parts of important codes).
ViewController.h
import <UIKit/UIKit.h>
import <SpriteKit/SpriteKit.h>
import <iAd/iAd.h>
#interface ViewController : UIViewController<ADBannerViewDelegate><br>
#end
GameOverScene.h
#import <SpriteKit/SpriteKit.h>
#class SpriteViewController;
#interface GameOverScene : SKScene {
}
#end
GameOverScene.m
#import "GameOverScene.h"
#import "NewGameScene.h"
#import "MainScene.h"
#import <Social/Social.h>
#implementation GameOverScene {
//The twitter button
SKSpriteNode *_twitterbutton;
}
- (id)initWithSize:(CGSize)size
{
if (self = [super initWithSize:size]) {
//Creating the twitterbutton with the twitterbutton image from Images.xcassets
_twitterbutton = [SKSpriteNode spriteNodeWithImageNamed:#"twitterbutton"];
[_twitterbutton setSize:CGSizeMake(50, 50)];
[_twitterbutton setPosition:CGPointMake(self.size.width/2, self.size.height/5 + 50)];
//Adding the twitter button
[self addChild:_twitterbutton];
//Again, this is important, otherwise we can't identify what button is pressed
_twitterbutton.name = #"twitterbutton";
[_twitterbutton setPosition:CGPointMake(self.size.width/2, self.size.height/5 + 50)]
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//Same as in NewGameScene menu
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInNode:self];
SKNode *node = [self nodeAtPoint:location];
//Is the twitter button touched?
if([node.name isEqualToString:#"twitterbutton"]){
if ([SLComposeViewController isAvailableForServiceType:SLServiceTypeTwitter]){
SLComposeViewController *tweetSheet = [SLComposeViewController composeViewControllerForServiceType:SLServiceTypeTwitter];
[tweetSheet setInitialText:#"TestTweet from the Game !!"];
[self presentViewController:tweetSheet animated:YES completion:nil];
**//Error:No visible #interface for 'GameOverScene' declares the selector "presentViewController":animated:completion:**
}
}
ViewControlloer.m
#import "ViewController.h"
#import "NewGameScene.h"
#implementation ViewController
//Loads the view onto our main class
- (void)loadView
{
self.view = [[SKView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
}
//Executes when view finishes loading
- (void)viewWillLayoutSubviews
{
[super viewDidLoad];
//Set the resize mode to flexible width and height
[self.view setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
//Create our view from our original view
//Make sure to leave originalContentView in, otherwise the app will crash
SKView *skView = (SKView *)self.originalContentView;
//We create a new NewGameScene according to the current dimensions
SKScene *scene = [NewGameScene sceneWithSize:skView.bounds.size];
//Create a transition class with animation type fade and a duration of .4 seconds
SKTransition *transition = [SKTransition fadeWithDuration:.4];
//Present the menu view (NewGameScene) with our fade in transition
[skView presentScene:scene transition:transition];
}
#end

Answer 1

You cannot present a viewController from within a SKScene as it is actually only being rendered on a SKView. You need a way to send a message to the viewController, which in turn will present the viewController. For this, you can use delegation.
Add the following protocol definition to your SKScene's .h file:
#protocol sceneDelegate <NSObject>
-(void)showShareScreen;
#end
And declare a delegate property in the interface:
#property (weak, nonatomic) id <sceneDelegate> delegate;
Then, at the point where you want to present the share screen, instead of the line:
[self presentViewController:tweetSheet animated:YES completion:nil];
Use this line:
[self.delegate showShareScreen];
Now, in your viewController's .h file, implement the protocol:
#interface ViewController : UIViewController <sceneDelegate>
And, in your .m file, add the following line before you present the scene:
scene.delegate = self;
Then add the following method there:
-(void)presentShareScreen
{
if ([SLComposeViewController isAvailableForServiceType:SLServiceTypeTwitter])
{
SLComposeViewController *tweetSheet = [SLComposeViewController
composeViewControllerForServiceType:SLServiceTypeTwitter];
[tweetSheet setInitialText:#"TestTweet from the Game !!"];
[self presentViewController:tweetSheet animated:YES completion:nil];
}
}
An alternate method would be to use NSNotificationCenter
Keep the -presentShareScreen method as described in the previous alternative.
Add the viewController as a listener to the notification in it's -viewDidLoad method:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(presentShareScreen) name:#"showShareScreen" object:nil];
Then, in the scene at the point where you want to show this viewController, use this line:
[[NSNotificationCenter defaultCenter] postNotificationName:#"showShareScreen" object:nil];