AutoScroll ViewPager

AutoScrollViewPager.java

import android.content.Context;
import android.os.Handler;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.animation.DecelerateInterpolator;
import android.widget.Scroller;

import java.lang.reflect.Field;


/**
 * BannerView Pager - custom auto scroll viewpager
 * Copyright (c) 2014年 Alan Lam. All rights reserved.
 * REF: http://stackoverflow.com/questions/8155257/slowing-speed-of-viewpager-controller-in-android
 */
public class AutoScrollViewPager extends ViewPager {

    private static final int SCROLL_DURATION = 1000;
    private static final int DEFAULT_CIRCULAR_DURATION = 4000;

    private Handler mHandler = new Handler();

    private boolean mAllowSwipe = true;
    private int mCurrentPos;
    private int mCircularDuration;
    private boolean autoplayDisableOnInteraction = true;

    private Runnable mChangePosRunnable = new Runnable() {
        @Override
        public void run() {
            int newPos = ++mCurrentPos;
            if (newPos >= getAdapter().getCount()) {
                newPos = 0;
                mCurrentPos = newPos;
            }
            setCurrentItem(newPos, true);
            if (mCurrentPos == getAdapter().getCount()-1) {
                mHandler.postDelayed(mBackToFirstRunnable, SCROLL_DURATION);
                mCurrentPos = 0;
            }
            mHandler.removeCallbacks(mChangePosRunnable);
            mHandler.postDelayed(mChangePosRunnable, mCircularDuration);
        }
    };

    private Runnable mBackToFirstRunnable = new Runnable() {
        @Override
        public void run() {
            mHandler.removeCallbacks(mBackToFirstRunnable);
            setCurrentItem(0, false);
        }
    };

    public AutoScrollViewPager(Context context) {
        super(context);
        setCustomScroller();
    }

    public AutoScrollViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        setCustomScroller();
    }

    public void setAllowSwipe(boolean allow) {
        mAllowSwipe = allow;
    }

    public void startCircular(int durationMillis) {
        mCurrentPos = 0; 
        mCircularDuration = durationMillis;
        stopCircular();
        mHandler.postDelayed(mChangePosRunnable, mCircularDuration);
    }

    /**
     * Start circular with default duration {@value #DEFAULT_CIRCULAR_DURATION}ms
     */
    public void startCircular() {
        startCircular(DEFAULT_CIRCULAR_DURATION);
    }

    public void stopCircular() {
        mHandler.removeCallbacks(mChangePosRunnable);
    }

    @Override
    public boolean onTouchEvent(MotionEvent arg0) {
        return mAllowSwipe?super.onTouchEvent(arg0):true;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent arg0) {
        return mAllowSwipe?super.onInterceptTouchEvent(arg0):false;
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        stopCircular();
    }
    
    public void setAutoplayDisableOnInteraction(boolean isAutoplayDisableOnInteraction){
        autoplayDisableOnInteraction = isAutoplayDisableOnInteraction;   
    }

    /**
     * Use reflection to set our custom Scroller
     * for longer animation duration
     */
    private void setCustomScroller() {
        try {
            Class<?> viewPager = ViewPager.class;
            Field scroller = viewPager.getDeclaredField("mScroller");
            scroller.setAccessible(true);
            scroller.set(this, new CustomScroller(getContext()));
        } catch (Exception e)  {
            e.printStackTrace();
        }
    }

    public class CustomScroller extends Scroller {

        public CustomScroller(Context context) {
            super(context, new DecelerateInterpolator());
        }

        @Override
        public void startScroll(int startX, int startY, int dx, int dy,
                                int duration) {
            super.startScroll(startX, startY, dx, dy, SCROLL_DURATION);
        }

    }

}