Adding Swipe Gesture in Android App

Question

I'm trying to add a swipe gesture to my app. I followed a tutorial but I can't seem to get it working. What am I doing wrong?

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class Home extends Activity {

        private static final int SWIPE_MIN_DISTANCE = 120;
        private static final int SWIPE_THRESHOLD_VELOCITY = 200;
        GridView gridMenu;
        private GestureDetector gestureDetector;

        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.home);

            gridMenu = (GridView)findViewById(R.id.gridMenu);

            gridMenu.setAdapter(new ImageAdapter(this));
            gridMenu.setHorizontalScrollBarEnabled(false);

            gestureDetector = new GestureDetector(this, new OnSwipeGestureListener());

            gridMenu.setOnItemClickListener(new OnItemClickListener(){
            public void onItemClick(AdapterView<?>parent, View v, int position, long id){

                Intent url;
                Bundle urlBundle = new Bundle(); 

                switch(position){
                case 0: 
                    // Public Affairs

                    url = new Intent(Home.this, PublicAffairs.class); 
                    urlBundle.putString("url", "http://kyfbnewsroom.com/category/public-affairs/feed");
                    url.putExtras(urlBundle);
                    startActivity(url);
                    break;

                case 1:
                    // Action Alerts  

                    url = new Intent(Home.this, ActionAlerts.class); 
                    urlBundle.putString("url", "http://kyfbnewsroom.com/category/public-affairs/notifications/feed");
                    url.putExtras(urlBundle);
                    startActivity(url);     
                    break;

                case 2:
                    // Market Updates 

                    url = new Intent(Home.this, MarketUpdates.class); 
                    urlBundle.putString("url", "http://kyfbnewsroom.com/category/market-updates/feed");
                    url.putExtras(urlBundle);
                    startActivity(url);  
                    break;

                case 3: 
                    // Ag Stories

                    url = new Intent(Home.this, AgNews.class); 
                    urlBundle.putString("url", "http://kyfbnewsroom.com/category/ag-news/feed");
                    url.putExtras(urlBundle);
                    startActivity(url);  
                    break;

                case 4:
                    // KFB News

                    url = new Intent(Home.this, KFBMagazine.class); 
                    urlBundle.putString("url", "http://kyfbnewsroom.com/category/kfb-news/feed/");
                    url.putExtras(urlBundle);
                    startActivity(url);  
                    break;

                case 5:
                   // Member Benefits


                    Intent member = new Intent(Home.this, MemberBenefits.class); 
                    startActivity(member);
                        //overridePendingTransition(R.anim.fadeon, R.anim.fadeoff); 
                    break;

                case 6:
                //Monthly Video

                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.youtube.com/user/kentuckyfarmbureau")));
                    break;

                case 7:
                    // Photos

                 // Intent flickr = new Intent(Home.this, Flickr.class);                    

                      // startActivity(flickr);
                        //overridePendingTransition(R.anim.fadeon, R.anim.fadeoff); 

                    // Farm Markets

                    Intent markets = new Intent(Home.this, RSFM.class);
                    startActivity(markets);
                    break;

                case 8:
                    // Social Media

                  Intent social = new Intent(Home.this, SocialMedia.class);                     
                  startActivity(social);
                 //overridePendingTransition(R.anim.fadeon, R.anim.fadeoff); 
                    break;
                }   
            }
           }); 
        }

        @Override
        public boolean onTouchEvent(MotionEvent event)
        {
            if (gestureDetector.onTouchEvent(event))
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        private class OnSwipeGestureListener extends GestureDetector.SimpleOnGestureListener
        {
            @Override
            public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
            {
                float deltaX = e2.getX() - e1.getX();
                if ((Math.abs(deltaX) < SWIPE_MIN_DISTANCE) || (Math.abs(velocityX) < SWIPE_THRESHOLD_VELOCITY))
                {
                    return false;
                }
                else
                {
                    if (deltaX < 0)
                    {
                        handleSwipeLeftToRight();
                    }
                    else
                    {
                        handleSwipeRightToLeft();
                    }
                }
                return true;
            }
        }

        private void handleSwipeLeftToRight()
        {
            System.out.println("Swipe Left to Right");
            Intent intent = new Intent(Home.this, RSFM.class);
            startActivity(intent);
        }

        private void handleSwipeRightToLeft()
        {
            System.out.println("Swipe Right to Left");
            Intent intent = new Intent(Home.this, RSFM.class);
            startActivity(intent);
        }



        /*
         * This method is used to check whether there is internet connection or not.
         */
        public boolean isConnect() {
            ConnectivityManager cm =
                (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo netInfo = cm.getActiveNetworkInfo();
            if (netInfo != null && netInfo.isConnectedOrConnecting()) {
                return true;
            }
            return false;
        }

    public class ImageAdapter extends BaseAdapter {

            Context mContext;
            public static final int ACTIVITY_CREATE = 10;

            public ImageAdapter(Context c){
                mContext = c;
            }

            public int getCount(){
                return MenuIcon.length;
            }

            public Object getItem(int position){
                return null;
            }

            public long getItemId(int position){
                return 0;
            }

            public View getView(int position, View convertView, ViewGroup parent){
                View v;
                if(convertView == null){
                    LayoutInflater li = getLayoutInflater();
                    v = li.inflate(R.layout.grid_layout, null);
                }else{
                    v = convertView;
                }

                ImageView imgIcon = (ImageView) v.findViewById(R.id.imgIcon);
                imgIcon.setImageResource(MenuIcon[position]);
                //TextView txtIcon = (TextView) v.findViewById (R.id.txtIcon);
                //txtIcon.setText(TextIcon[position]);

                return v;
            }

            private Integer[] MenuIcon = {
                    R.drawable.publicaffairs, R.drawable.actionalerts, R.drawable.marketupdates, 
                    R.drawable.agnews, R.drawable.kfbmagazine, R.drawable.memberbenefits, R.drawable.monthlyvideo, 
                    R.drawable.roadsidemarkets, R.drawable.socialmedia
            };


        }


} 

Answer 1

Do you want to catch the touches on the GridView?

Your onTouchEvent() is only called when the touched View (in your Activity) doesn't handle it itself (like an ImageView). The GridView does (cause is clickable)!

Try setting a OnTouchListener on your GridView and push those events to your GestureDetector.