ios - How to programmatically take a screenshot and share it to a social network? -

i attempting programmatically take screenshot , share social media network when button clicked, however, cannot quite figure out how so. appreciate

    -(void)touchesbegan:(nsset *)touches withevent:(uievent *)event { /* called when touch begins */ uitouch *touch = [touches anyobject]; cgpoint location = [touch locationinnode:self]; sknode *node = [self nodeatpoint:location];  if ([node.name isequaltostring:@"twitter"]){     [self.button play];      twitter = [[slcomposeviewcontroller alloc] init];     twitter = [slcomposeviewcontroller composeviewcontrollerforservicetype:slservicetypetwitter];     [twitter setinitialtext:@""];      uiviewcontroller *twit = self.view.window.rootviewcontroller;     [twit presentviewcontroller: twitter animated: yes completion:null]; }   }