Using GestureDetector to detect user swipe, onFling()

Previous exercise demonstrate "Bi-direction sliding ViewFlipper" controlled by buttons. This exercise show how to implements GestureDetector.OnGestureListener to detect user swipe to update ViewFlipper.

package com.example.androidviewflipper;

import android.os.Bundle;
import android.app.Activity;
import android.support.v4.view.GestureDetectorCompat;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.Toast;
import android.widget.ViewFlipper;

public class MainActivity extends Activity implements 
 GestureDetector.OnGestureListener {
 
 private GestureDetectorCompat mDetector;

 Button buttonPrev, buttonNext;
 ViewFlipper viewFlipper;

 Animation slide_in_left, slide_out_right;
 Animation slide_in_right, slide_out_left;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  mDetector = new GestureDetectorCompat(this,this);

  buttonPrev = (Button) findViewById(R.id.prev);
  buttonNext = (Button) findViewById(R.id.next);
  viewFlipper = (ViewFlipper) findViewById(R.id.viewflipper);

  slide_in_left = AnimationUtils.loadAnimation(this,
    R.anim.slide_in_left);
  slide_out_right = AnimationUtils.loadAnimation(this,
    R.anim.slide_out_right);
  
  slide_in_right = AnimationUtils.loadAnimation(this,
    R.anim.slide_in_right);
  slide_out_left = AnimationUtils.loadAnimation(this,
    R.anim.slide_out_left);
  
  //viewFlipper.setInAnimation(slide_in_left);
  //viewFlipper.setOutAnimation(slide_out_right);

  buttonPrev.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
    viewFlipper.setInAnimation(slide_in_right);
    viewFlipper.setOutAnimation(slide_out_left);
    viewFlipper.showPrevious();
   }
  });

  buttonNext.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
    viewFlipper.setInAnimation(slide_in_left);
    viewFlipper.setOutAnimation(slide_out_right);
    viewFlipper.showNext();
   }
  });
  ;
 }

 @Override
 public boolean onTouchEvent(MotionEvent event) {
  this.mDetector.onTouchEvent(event);
  return super.onTouchEvent(event);
 }

 @Override
 public boolean onDown(MotionEvent arg0) {
  // TODO Auto-generated method stub
  return false;
 }

 @Override
 public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
   float velocityY) {
  float sensitvity = 50;
  
  if((e1.getX() - e2.getX()) > sensitvity){
   viewFlipper.setInAnimation(slide_in_right);
   viewFlipper.setOutAnimation(slide_out_left);
   viewFlipper.showPrevious();
   Toast.makeText(MainActivity.this, 
     "Previous", Toast.LENGTH_SHORT).show();
  }else if((e2.getX() - e1.getX()) > sensitvity){
   viewFlipper.setInAnimation(slide_in_left);
   viewFlipper.setOutAnimation(slide_out_right);
   viewFlipper.showNext();
   Toast.makeText(MainActivity.this, 
     "Next", Toast.LENGTH_SHORT).show();
  }
  
  return true;
 }

 @Override
 public void onLongPress(MotionEvent e) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
   float distanceY) {
  // TODO Auto-generated method stub
  return false;
 }

 @Override
 public void onShowPress(MotionEvent e) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public boolean onSingleTapUp(MotionEvent e) {
  // TODO Auto-generated method stub
  return false;
 }

}

Keep using the layout and animation XML files in last exercise.

Download the files.


Next:
- Detect Gesture by implementing GestureDetector.SimpleOnGestureListener