Detect Gesture by implementing GestureDetector.SimpleOnGestureListener

This example show how to detect user gesture by implementing GestureDetector.SimpleOnGestureListener. It have the same result as last exercise of "GestureDetector".

GestureDetector.SimpleOnGestureListener provides an implementation for all of the on<TouchEvent> methods by returning false for all of them. Thus we can override only the methods we care about. In our application, we have to detect onFling() only. So we can extend GestureDetector.SimpleOnGestureListener instead of implementing the GestureDetector.OnGestureListener interface.

MainActivity.java

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{
 
 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, new MyGestureListener());

  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);

  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);
 }

 class MyGestureListener extends GestureDetector.SimpleOnGestureListener {

  @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;
  }
    }
}

Keep using the layout and animation XML files in the exercise of "Bi-direction sliding ViewFlipper".

Download the files.

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

Bi-direction sliding ViewFlipper

Last exercise show a Example of ViewFlipper. It always slide from left to right, no matter you click previous or next button. In this exercise, we will implement bi-direction sliding. Slide to right if you click next button, slide left if you click previous button. This technique can also be applied on ViewAnimator, TextSwitcher, ImageSwitcher and ViewSwitcher.

Create /res/anim/ folder, and create the following XMLs to define the animation.

slide_in_left.xml:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
 <translate android:fromXDelta="-50%p" android:toXDelta="0"
            android:duration="1000"/>
 <alpha android:fromAlpha="0.0" android:toAlpha="1.0"
            android:duration="1000" />
</set>

slide_in_right.xml:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
 <translate android:fromXDelta="50%p" android:toXDelta="0"
            android:duration="1000"/>
 <alpha android:fromAlpha="0.0" android:toAlpha="1.0"
            android:duration="1000" />
</set>

slide_out_left.xml:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
 <translate android:fromXDelta="0" android:toXDelta="-50%p"
            android:duration="1000"/>
 <alpha android:fromAlpha="1.0" android:toAlpha="0.0"
            android:duration="1000" />
</set>

slide_out_right.xml:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
 <translate android:fromXDelta="0" android:toXDelta="50%p"
            android:duration="1000"/>
 <alpha android:fromAlpha="1.0" android:toAlpha="0.0"
            android:duration="1000" />
</set>

Modify layout file, all child View of <ViewFlipper> have android:layout_width="match_parent".

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/prev"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="previous" />

        <Button
            android:id="@+id/next"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="next" />
    </LinearLayout>

    <ViewFlipper
        android:id="@+id/viewflipper"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_launcher" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:orientation="vertical" >

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="- Button 2 -" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="LinearLayout 2" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:orientation="vertical" >

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Enter something" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="LinearLayout 3" />
        </LinearLayout>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="ViewFlipper is a simple ViewAnimator that 
     will animate between two or more views that 
     have been added to it. Only one child is shown 
     at a time. If requested, can automatically 
     flip between each child at a regular interval." />
    </ViewFlipper>

</LinearLayout>

Main code;

package com.example.androidviewflipper;

import android.os.Bundle;
import android.app.Activity;
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.ViewFlipper;

public class MainActivity extends Activity {

 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);

  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();
   }
  });
  ;
 }

}

Next: Using GestureDetector to detect user swipe, onFling()

Example of ViewFlipper

android.widget.ViewFlipper is a simple ViewAnimator that will animate between two or more views that have been added to it. Only one child is shown at a time. If requested, can automatically flip between each child at a regular interval.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/prev"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="previous" />

        <Button
            android:id="@+id/next"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="next" />
    </LinearLayout>

    <ViewFlipper
        android:id="@+id/viewflipper"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_launcher" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:orientation="vertical" >

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="- Button 2 -" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="LinearLayout 2" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:orientation="vertical" >

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Enter something" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="LinearLayout 3" />
        </LinearLayout>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="ViewFlipper is a simple ViewAnimator that 
     will animate between two or more views that 
     have been added to it. Only one child is shown 
     at a time. If requested, can automatically 
     flip between each child at a regular interval." />
    </ViewFlipper>

</LinearLayout>

package com.example.androidviewflipper;

import android.os.Bundle;
import android.app.Activity;
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.ViewFlipper;

public class MainActivity extends Activity {

 Button buttonPrev, buttonNext;
 ViewFlipper viewFlipper;

 Animation slide_in_left, slide_out_right;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

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

  slide_in_left = AnimationUtils.loadAnimation(this,
    android.R.anim.slide_in_left);
  slide_out_right = AnimationUtils.loadAnimation(this,
    android.R.anim.slide_out_right);

  viewFlipper.setInAnimation(slide_in_left);
  viewFlipper.setOutAnimation(slide_out_right);

  buttonPrev.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
    viewFlipper.showPrevious();
   }
  });

  buttonNext.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
    viewFlipper.showNext();
   }
  });
  ;
 }

}