How to set onFling() event of Gesture on ScrollView in android?

Question

I set the onFling() event of Gesture on ScrollView, but it is not working on ScrollView,

package com.doubletap;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.OnDoubleTapListener;
import android.view.GestureDetector.OnGestureListener;
import android.view.MotionEvent;
import android.widget.TextView;

public class DoubleTapActivity extends Activity implements OnGestureListener 
{
private GestureDetector gd;

private TextView tvTap;

String TAG = getClass().getSimpleName();

private static final int SWIPE_MIN_DISTANCE = 120;
private static final int SWIPE_MAX_OFF_PATH = 250;
private static final int SWIPE_THRESHOLD_VELOCITY = 200;

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    tvTap = (TextView)findViewById(R.id.tvTap);

    gd = new GestureDetector(this);

    gd.setOnDoubleTapListener(new OnDoubleTapListener()
    {
        @Override
        public boolean onDoubleTap(MotionEvent e) 
        {
            return false;
        }

        @Override
        public boolean onDoubleTapEvent(MotionEvent e) 
        {
            return false;
        }

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) 
        {
            return false;
        }
    });
}

@Override
public boolean onTouchEvent(MotionEvent event) 
{
    return gd.onTouchEvent(event);//return the double tap events
}

@Override
public boolean onDown(MotionEvent e) 
{
    return false;
}

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

    try {
        if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
        {
             return false;
        }

        if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
             tvTap.setText("Flip Right to Left");
             Log.v(TAG, "Right to Left");
        }  else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
            tvTap.setText("Flip Left to Right");
             Log.v(TAG, "Left to Right");
        }
    } catch (Exception e)
    {

    }
    return false;
}

@Override
public void onLongPress(MotionEvent e) 
{
}

@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) 
{
    return false;
}

@Override
public void onShowPress(MotionEvent e) 
{
}

@Override
public boolean onSingleTapUp(MotionEvent e) 
{
    return false;
}
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="@string/hello"
    android:textStyle="bold" />
<TextView
    android:id="@+id/tvTap"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dip" >
</TextView>
<TextView
    android:id="@+id/tvTapEvent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dip" >
</TextView>
<ScrollView
    android:id="@+id/scroll"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button1" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button2" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button3" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button4" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button5" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button6" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button7" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button8" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button9" />
        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Button10" />
    </LinearLayout>
</ScrollView>

does anybody know how to implement the onFling() event on Scrollview ??

Answer 1

This works for me. Hopefully you can add your double tap actions in here.

    public class ScrollViewFling extends Activity 
{
    private GestureDetector mGesture;

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.scrollviewfling);
        mGesture = new GestureDetector(this, mOnGesture);

    }
    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        boolean handled = super.dispatchTouchEvent(ev);
        handled = mGesture.onTouchEvent(ev);    
        return handled;
    }

    private OnGestureListener mOnGesture = new GestureDetector.SimpleOnGestureListener() {

        @Override
        public boolean onDown(MotionEvent e) {
            return false;
        }

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            Log.v("fling", "Flinged.");
            return true;
        }

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            return false;
        }
    };
};