Touch Practice

// StoreScene.h
#include "cocos2d.h"

class StoreScene : public cocos2d::CCLayer {
private:
   cocos2d::CCLayerColor * mScrollLayer;
   cocos2d::CCMenu * mMenu;
   cocos2d::CCPoint mTouchStartPos;

public:
   static cocos2d::CCScene * scene();
   virtual void init();
   CREATE_FUNC( StoreScene ) // LAYER_CREATE_FUNC is deprecated in cocos2d-x 2.0.4

   void drawButtons();

   virtual bool ccTouchBegan( cocos2d::CCTouch * touch, cocos2d::CCEvent * event );
   virtual void ccTouchMoved( cocos2d::CCTouch * touch, cocos2d::CCEvent * event );
   virtual void ccTouchEnded( cocos2d::CCTouch * touch, cocos2d::CCEvent * event );
}

// StoreScene.cpp
#include "StoreScene.h"

// GraphicMacros.h contains functions like getWinWize() and the like.
#include "GraphicMacros.h"
USING_NS_CC;

/** cocos2d-x common functions
 *    - Functions like create() and scene() here.
 */

bool StoreScene::init() {
   if ( !CCLayer::init() ) return false;

   // Create the scrolling layer
   mScrollLayer = CCLayerColor::create( ccc4( 255, 255, 255, 255 ), getWinSize().width, getWinSize().height );
   this -> addChild( mScrollLayer );

   // Create CCMenu object
   mMenu = CCMenu::create();
   mMenu -> setPosition( CCPointZero );
   this -> addChild( mMenu );

   // Fill the scroll layer with items
   this -> drawButtons();

   // Enable touch
   this -> setTouchEnabled( true );
   CCDirector::sharedDirector() -> getTouchDispatcher() -> addTargetedDelegate( this, 0, true );

   // Report success.
   return true;
}

void StoreScene::drawButtons() {
   // Draw a bunch of CCMenuItemImage objects.
   for ( int i = 0; i <= 10; i++ ) {
      CCMenuItemImage * menu = CCMenuItemImage::create( "btn_on.png", "btn_off.png", this, menu_selector( StoreScene::doPlay );
      menu -> setTag( i );
      mMenu -> addChild( menu );
   }
}

bool StoreScene::ccTouchBegan( CCTouch * touch, CCEvent * event ) {
   // Save touch position
   mTouchStartPos = this -> convertTouchToNodeSpace( touch );

   // Swallow touch
   return true;
}

void StoreScene::ccTouchMoved( CCTouch * touch, CCEvent * event ) {
   // Calculate difference in touch
   CCPoint touchLoc = this -> convertTouchToNodeSpace( touch );
   CCPoint oldLoc = this -> convertToNodeSpace( touch -> getPreviousLocationInView() );
   CCPoint gap = ccpSub( touchLoc, oldLoc );

   // Drag mMenu towards touch location, but not changing y-position
   CCPoint newLoc = ccpAdd( mMenu -> getPosition(), gap );
   mMenu -> setPosition( CCPointMake( newLoc.x, mMenu -> getPosition().y ) );
}

void StoreScene::ccTouchEnded( CCTouch * touch, CCEvent * event ) {
   // Calculate touch length (along x-axis )
   CCPoint touchLoc = this -> convertTouchToNodeSpace( touch );
   CCPoint gap = ccpSub( touchLoc, mTouchStartPos );

   // Check gap length
   if ( gap.x < -200 ) {
      // Touch is towards the left. Do something about it.
   } else if ( gap.x > 200 ) {
      // Touch is towards the right. Do something about it.
   } else {
      // Touch is not long enough. Reset mMenu position. ( assume original position is CCPointZero )
      mMenu -> runAction( CCMoveTo::create( 0.20f, CCPointZero ) );
   }
}