<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="@string/hello"
        android:gravity="center" />
 <com.machete.FlingAndScrollViewer.FlingAndScrollViewer
        android:layout_width="fill_parent" android:layout_height="fill_parent"
        android:id="@+id/flingScrollViewer">
        <ScrollView android:id="@+id/scrollView1"
            android:background="#FF8000" android:layout_height="fill_parent"
            android:layout_width="fill_parent">
            <LinearLayout android:id="@+id/linearLayout1"
                android:layout_height="fill_parent" android:layout_width="fill_parent"
                android:orientation="vertical">
                <TextView android:id="@+id/TextView01" android:text="1"
                    android:textColor="#ffffff" android:layout_width="fill_parent"
                    android:layout_weight="1" android:gravity="center"
                    android:layout_height="wrap_content" android:textSize="500dip"></TextView>
            </LinearLayout>
        </ScrollView>
     <ScrollView android:id="@+id/scrollView2"
            android:background="#0080FF" android:layout_height="fill_parent"
            android:layout_width="fill_parent">
            <LinearLayout android:id="@+id/linearLayout2"
                android:layout_height="fill_parent" android:layout_width="fill_parent"
                android:orientation="vertical">
                <TextView android:id="@+id/TextView02" android:text="2"
                    android:textColor="#ffffff" android:layout_width="fill_parent"
                    android:layout_weight="1" android:gravity="center"
                    android:layout_height="wrap_content" android:textSize="500dip"></TextView>
            </LinearLayout>
        </ScrollView>
     <ScrollView android:id="@+id/scrollView3"
            android:background="#00FF00" android:layout_height="fill_parent"
            android:layout_width="fill_parent">
            <LinearLayout android:id="@+id/linearLayout3"
                android:layout_height="fill_parent" android:layout_width="fill_parent"
                android:orientation="vertical">
                <TextView android:id="@+id/TextView03" android:text="3"
                    android:textColor="#ffffff" android:layout_width="fill_parent"
                    android:layout_weight="1" android:gravity="center"
                    android:layout_height="wrap_content" android:textSize="500dip"></TextView>
            </LinearLayout>
        </ScrollView>
 </com.machete.FlingAndScrollViewer.FlingAndScrollViewer>
</LinearLayout>

public class Main  extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        FlingAndScrollViewer flingAndScrollViewer =
        (FlingAndScrollViewer) findViewById(R.id.flingScrollViewer);
        flingAndScrollViewer.setInitialPosition(0); //set the initial position
    }
}

public class FlingAndScrollViewer extends ViewGroup {
    private Scroller mScroller;
    private VelocityTracker mVelocityTracker;
    private int mScrollX = 0;
    private int mCurrentScreen = 0;
    private float mLastMotionX;
    private static final String LOG_TAG = "FlingAndScrollViewer";
    private static final int SNAP_VELOCITY = 1000;
    private final static int TOUCH_STATE_REST = 0;
    private final static int TOUCH_STATE_SCROLLING = 1;
    private int mTouchState = TOUCH_STATE_REST;
    private int mTouchSlop = 0;

    public FlingAndScrollViewer(Context context) {
        super(context);
        mScroller = new Scroller(context);
        mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
        this.setLayoutParams(new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.FILL_PARENT));
    }

    public FlingAndScrollViewer(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = getContext().obtainStyledAttributes(attrs,
                R.styleable.FlingAndScrollViewer);
        mCurrentScreen = a.getInteger(
                R.styleable.FlingAndScrollViewer_default_screen, 0);
        mScroller = new Scroller(context);
        mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
        this.setLayoutParams(new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.FILL_PARENT));
    }

    public void setInitialPosition(int initialPosition) {
        mCurrentScreen = initialPosition;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        /*
         * This method JUST determines whether we want to intercept the motion.
         * If we return true, onTouchEvent will be called and we do the actual
         * scrolling there.
         */
     /*
         * Shortcut the most recurring case: the user is in the dragging state
         * and he is moving his finger. We want to intercept this motion.
         */
        final int action = ev.getAction();
        if ((action == MotionEvent.ACTION_MOVE)
                , (mTouchState != TOUCH_STATE_REST)) {
            return true;
        }
     final float x = ev.getX();
     switch (action) {
        case MotionEvent.ACTION_MOVE:
            /*
             * mIsBeingDragged == false, otherwise the shortcut would have
             * caught it. Check whether the user has moved far enough from his
             * original down touch.
             */
         /*
             * Locally do absolute value. mLastMotionX is set to the y value of
             * the down event.
             */
            final int xDiff = (int) Math.abs(x - mLastMotionX);
         boolean xMoved = xDiff > mTouchSlop;
         if (xMoved) {
                // Scroll if the user moved far enough along the X axis
                mTouchState = TOUCH_STATE_SCROLLING;
            }
            break;
     case MotionEvent.ACTION_DOWN:
            // Remember location of down touch
            mLastMotionX = x;
         /*
             * If being flinged and user touches the screen, initiate drag;
             * otherwise don't. mScroller.isFinished should be false when being
             * flinged.
             */
            mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
                    : TOUCH_STATE_SCROLLING;
            break;
     case MotionEvent.ACTION_CANCEL:
        case MotionEvent.ACTION_UP:
            // Release the drag
            mTouchState = TOUCH_STATE_REST;
            break;
        }
     /*
         * The only time we want to intercept motion events is if we are in the
         * drag mode.
         */
        return mTouchState != TOUCH_STATE_REST;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
     if (mVelocityTracker == null) {
            mVelocityTracker = VelocityTracker.obtain();
        }
        mVelocityTracker.addMovement(event);
     final int action = event.getAction();
        final float x = event.getX();
     switch (action) {
        case MotionEvent.ACTION_DOWN:
            Log.i(LOG_TAG, "event : down");
            /*
             * If being flinged and user touches, stop the fling. isFinished
             * will be false if being flinged.
             */
            if (!mScroller.isFinished()) {
                mScroller.abortAnimation();
            }
         // Remember where the motion event started
            mLastMotionX = x;
            break;
        case MotionEvent.ACTION_MOVE:
            // Log.i(LOG_TAG,"event : move");
            // if (mTouchState == TOUCH_STATE_SCROLLING) {
            // Scroll to follow the motion event
            final int deltaX = (int) (mLastMotionX - x);
            mLastMotionX = x;
         // Log.i(LOG_TAG, "event : move, deltaX " + deltaX + ", mScrollX " +
            // mScrollX);
         if (deltaX < 0) {
                if (mScrollX > 0) {
                    scrollBy(Math.max(-mScrollX, deltaX), 0);
                }
            } else if (deltaX > 0) {
                final int availableToScroll = getChildAt(getChildCount() - 1)
                        .getRight() - mScrollX - getWidth();
                if (availableToScroll > 0) {
                    scrollBy(Math.min(availableToScroll, deltaX), 0);
                }
            }
            // }
            break;
        case MotionEvent.ACTION_UP:
            Log.i(LOG_TAG, "event : up");
            // if (mTouchState == TOUCH_STATE_SCROLLING) {
            final VelocityTracker velocityTracker = mVelocityTracker;
            velocityTracker.computeCurrentVelocity(1000);
            int velocityX = (int) velocityTracker.getXVelocity();
         if (velocityX > SNAP_VELOCITY , mCurrentScreen > 0) {
                // Fling hard enough to move left
                snapToScreen(mCurrentScreen - 1);
            } else if (velocityX < -SNAP_VELOCITY
                    , mCurrentScreen < getChildCount() - 1) {
                // Fling hard enough to move right
                snapToScreen(mCurrentScreen + 1);
            } else {
                snapToDestination();
            }
         if (mVelocityTracker != null) {
                mVelocityTracker.recycle();
                mVelocityTracker = null;
            }
            // }
            mTouchState = TOUCH_STATE_REST;
            break;
        case MotionEvent.ACTION_CANCEL:
            Log.i(LOG_TAG, "event : cancel");
            mTouchState = TOUCH_STATE_REST;
        }
        mScrollX = this.getScrollX();
     return true;
    }

    private void snapToDestination() {
        final int screenWidth = getWidth();
        final int whichScreen = (mScrollX + (screenWidth / 2)) / screenWidth;
        Log.i(LOG_TAG, "from des");
        snapToScreen(whichScreen);
    }

    public void snapToScreen(int whichScreen) {
        Log.i(LOG_TAG, "snap To Screen " + whichScreen);
        mCurrentScreen = whichScreen;
        final int newX = whichScreen * getWidth();
        final int delta = newX - mScrollX;
        mScroller.startScroll(mScrollX, 0, delta, 0, Math.abs(delta) * 2);
        invalidate();
    }

    public void setToScreen(int whichScreen) {
        Log.i(LOG_TAG, "set To Screen " + whichScreen);
        mCurrentScreen = whichScreen;
        final int newX = whichScreen * getWidth();
        mScroller.startScroll(newX, 0, 0, 0, 10);
        invalidate();
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childLeft = 0;
        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != View.GONE) {
                final int childWidth = child.getMeasuredWidth();
                child.layout(childLeft, 0, childLeft + childWidth,
                        child.getMeasuredHeight());
                childLeft += childWidth;
            }
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        final int width = MeasureSpec.getSize(widthMeasureSpec);
        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        if (widthMode != MeasureSpec.EXACTLY) {
            throw new IllegalStateException("error mode.");
        }
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        if (heightMode != MeasureSpec.EXACTLY) {
            throw new IllegalStateException("error mode.");
        }
        // The children are given the same width and height as the workspace
        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
        }
        Log.i(LOG_TAG, "moving to screen " + mCurrentScreen);
        scrollTo(mCurrentScreen * width, 0);
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            mScrollX = mScroller.getCurrX();
            scrollTo(mScrollX, 0);
            postInvalidate();
        }
    }

    /**
     * Return the parceable instance to be saved
     */
    @Override
    protected Parcelable onSaveInstanceState() {
        final SavedState state = new SavedState(super.onSaveInstanceState());
        state.currentScreen = mCurrentScreen;
        return state;
    }

    /**
     * Restore the previous saved current screen
     */
    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        SavedState savedState = (SavedState) state;
        super.onRestoreInstanceState(savedState.getSuperState());
        if (savedState.currentScreen != -1) {
            mCurrentScreen = savedState.currentScreen;
        }
    }

    // ========================= INNER CLASSES ==============================
    public interface onViewChangedEvent {
        void onViewChange(int currentViewIndex);
    }

    /**
     * A SavedState which save and load the current screen
     */
    public static class SavedState extends BaseSavedState {
        int currentScreen = -1;

        /**
         * Internal constructor
         *
         * @param superState
         */
        SavedState(Parcelable superState) {
            super(superState);
        }

        /**
         * Private constructor
         *
         * @param in
         */
        private SavedState(Parcel in) {
            super(in);
            currentScreen = in.readInt();
        }

        /**
         * Save the current screen
         */
        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeInt(currentScreen);
        }

        /**
         * Return a Parcelable creator
         */
        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="FlingAndScrollViewer">
        <attr name="default_screen" format="integer"/>
    </declare-styleable>
</resources>