Swipe or OnFling Event Android

This  is a simple application Demonstrating Swipe or onFling() event on ListView.

you can download the source code of this project from  google drive  https://drive.google.com/folderview?id=0BySLpWhqmbbdSVB4M0hXb0VxcU0&usp=sharing
click on the above link ->sign into  your  google account ->add this to your google drive -> open it in google drive and download it.

1.Following is the MainActivity (DemoSwipe.java) of the application

package com.arun.demolistviewswipe;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class DemoSwipe extends Activity {
 ListView lvCountry;
 String[] country = { "India", "USA", "Russsia", "China", "Pakistan",
   "Canada", "UK" };
 SwipeGestureListener gestureListener;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  lvCountry = (ListView) findViewById(R.id.lv_country);
  ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(
    DemoSwipe.this, android.R.layout.simple_list_item_1, country);
  lvCountry.setAdapter(arrayAdapter);
  gestureListener = new SwipeGestureListener(DemoSwipe.this);
  lvCountry.setOnTouchListener(gestureListener);

 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }

 class SwipeGestureListener extends SimpleOnGestureListener implements
   OnTouchListener {
  Context context;
  GestureDetector gDetector;
  static final int SWIPE_MIN_DISTANCE = 120;
  static final int SWIPE_MAX_OFF_PATH = 250;
  static final int SWIPE_THRESHOLD_VELOCITY = 200;

  public SwipeGestureListener() {
   super();
  }

  public SwipeGestureListener(Context context) {
   this(context, null);
  }

  public SwipeGestureListener(Context context, GestureDetector gDetector) {

   if (gDetector == null)
    gDetector = new GestureDetector(context, this);

   this.context = context;
   this.gDetector = gDetector;
  }

  @Override
  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
    float velocityY) {

   final int position = lvCountry.pointToPosition(
     Math.round(e1.getX()), Math.round(e1.getY()));

   String countryName = (String) lvCountry.getItemAtPosition(position);

   if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH) {
    if (Math.abs(e1.getX() - e2.getX()) > SWIPE_MAX_OFF_PATH
      || Math.abs(velocityY) < SWIPE_THRESHOLD_VELOCITY) {
     return false;
    }
    if (e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this, "bottomToTop" + countryName,
       Toast.LENGTH_SHORT).show();
    } else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this,
       "topToBottom  " + countryName, Toast.LENGTH_SHORT)
       .show();
    }
   } else {
    if (Math.abs(velocityX) < SWIPE_THRESHOLD_VELOCITY) {
     return false;
    }
    if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this,
       "swipe RightToLeft " + countryName, 5000).show();
    } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this,
       "swipe LeftToright  " + countryName, 5000).show();
    }
   }

   return super.onFling(e1, e2, velocityX, velocityY);

  }

  @Override
  public boolean onTouch(View v, MotionEvent event) {

   return gDetector.onTouchEvent(event);
  }

  public GestureDetector getDetector() {
   return gDetector;
  }

 }
}

>>>> To include Swipe  Event in our Activity we need a class which extends SimpleOnGestureListener and implements OnTouchListener  (SwipeGestureListener- in the above example). we need a constructor for this class and we need to @override the onFling(..),onTouch(..) events.Swipe event is controlled by OnFling() method. we can control LeftToRight ,RightToleft , BottomToTop, TopToBottom  swipe events using this.

@Override
  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
    float velocityY) {

   final int position = lvCountry.pointToPosition(
     Math.round(e1.getX()), Math.round(e1.getY()));

   String countryName = (String) lvCountry.getItemAtPosition(position);

   if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH) {
    if (Math.abs(e1.getX() - e2.getX()) > SWIPE_MAX_OFF_PATH
      || Math.abs(velocityY) < SWIPE_THRESHOLD_VELOCITY) {
     return false;
    }
    if (e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this, "bottomToTop" + countryName,
       Toast.LENGTH_SHORT).show();
    } else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this,
       "topToBottom  " + countryName, Toast.LENGTH_SHORT)
       .show();
    }
   } else {
    if (Math.abs(velocityX) < SWIPE_THRESHOLD_VELOCITY) {
     return false;
    }
    if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this,
       "swipe RightToLeft " + countryName, 5000).show();
    } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE) {
     Toast.makeText(DemoSwipe.this,
       "swipe LeftToright  " + countryName, 5000).show();
    }
   }

   return super.onFling(e1, e2, velocityX, velocityY);

  }

>>> then we need to create  instance of the  SwipeGestureListener
in our mainActivity (DemoSwipe - in the above Example) and set the instance to the onTochEvent of the ListView .

SwipeGestureListener gestureListener;
gestureListener = new SwipeGestureListener(DemoSwipe.this);
lvCountry.setOnTouchListener(gestureListener);

2. Main.xml file  is given below 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/LinearLayout1"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >


    <ListView

        android:id="@+id/lv_country"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

    </ListView>


</LinearLayout>