package com.givenjazz.android;

import android.content.Context;
import android.hardware.SensorManager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
import android.widget.Gallery;

public class OneFlingGallery extends Gallery {
    private float mDeceleration;
    private float mDistanceX;

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

    public OneFlingGallery(Context context, AttributeSet attrs) {
    super(context, attrs);
    float ppi = context.getResources().getDisplayMetrics().density * 160.0f;
    mDeceleration = SensorManager.GRAVITY_EARTH // g (m/s^2)
        * 39.37f // inch/meter
        * ppi // pixels per inch
        * ViewConfiguration.getScrollFriction();
    }

    public OneFlingGallery(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    float ppi = context.getResources().getDisplayMetrics().density * 160.0f;
    mDeceleration = SensorManager.GRAVITY_EARTH // g (m/s^2)
        * 39.37f // inch/meter
        * ppi // pixels per inch
        * ViewConfiguration.getScrollFriction();
    }

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

    float toMoveDistance = getWidth() - Math.abs(mDistanceX);
    float maxVelocity = (float) Math.sqrt(toMoveDistance * mDeceleration
        * 2);
    float revisedVelocityX = 0;

    if (velocityX > 0) {
        revisedVelocityX = Math.min(velocityX, maxVelocity);
    } else {
        revisedVelocityX = Math.max(velocityX, -maxVelocity);
    }

    return super.onFling(e1, e2, revisedVelocityX, velocityY);
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
        float distanceY) {
    mDistanceX += distanceX;
    return super.onScroll(e1, e2, distanceX, distanceY);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        mDistanceX = 0;
    }
    return super.onTouchEvent(event);
    }
}