升级版draggedLayout *固定其中一个按钮*

系统桌面的图标是可以拖拽，大家用起来好像也很习惯。不知道从什么时候开始，应用中的gridview也常常被人拿来做类似的效果。像支付宝，uc，还有一些新闻类的app都有拖拽控件的效果。对于item数量比较多的情况使用拖拽控件是一个比较不错的选择。
然后客户就开始想象自己有很多很多的类似小功能，然后就出现了这篇blog。
虽然只有十个不到的功能按钮，然而我们要有雄伟的蓝图，以后我们会有好多好多的功能的。用户使用的时候就会觉得不方便的。我们需要把按钮的排序权利交给用户。然后我们还要展开收缩的功能。为了界面的整洁美观，一行就放5个按钮，第一行的第五个按钮就是更多按钮，这是用来展开收拢的。按钮全部来自网络，我们需要随时更新的。
其实拖拽还是简单的，展开收拢也没什么难度。然而为什么要让第五个按钮成为更多呢？！？！？！？！？瞬间日子就很难过了。

有一个失败的例子就是继承自gridview的拖拽控件，动画效果十分生硬，还有各种闪烁的情况。想想网上的大神们应该没有写过这一类的帅气的空间吧。

感谢 http://blog.csdn.net/sk719887916/article/details/40074663 博主 为我提供了这个帅帅拖拽基础控件。

package com.kting.baijinka.util;/*import java.util.ArrayList;import android.content.Context;import android.database.DataSetObserver;import android.graphics.Rect;import android.os.Parcel;import android.os.Parcelable;import android.support.v4.view.MotionEventCompat;import android.support.v4.view.VelocityTrackerCompat;import android.support.v4.view.ViewCompat;import android.support.v4.view.ViewConfigurationCompat;import android.util.AttributeSet;import android.util.Log;import android.view.HapticFeedbackConstants;import android.view.MotionEvent;import android.view.VelocityTracker;import android.view.View;import android.view.ViewConfiguration;import android.view.ViewGroup;import android.view.ViewParent;import android.view.animation.AlphaAnimation;import android.view.animation.AnimationSet;import android.view.animation.Interpolator;import android.view.animation.ScaleAnimation;import android.view.animation.TranslateAnimation;import android.widget.Adapter;import android.widget.AdapterView.OnItemClickListener;import android.widget.AdapterView.OnItemLongClickListener;import android.widget.Scroller;import com.kting.baijinka.adapter.ICBCButtonAdapter;/** * Zaker style grid view pager, support dragging & rearrange, using as zaker's main screen. */public class DraggableGridViewPager extends ViewGroup {    private static final String TAG = "DraggableGridViewPager";    private static final boolean DEBUG = true;    private static final boolean USE_CACHE = false;    private static void DEBUG_LOG(String msg) {        if (DEBUG) {            Log.v(TAG, msg);        }    }    // layout    private static final int DEFAULT_COL_COUNT = 5;    private static final int DEFAULT_ROW_COUNT = 12;    private static final int DEFAULT_GRID_GAP = 2; // gap between grids (dips)    private static final int MAX_SETTLE_DURATION = 600; // ms    private static final int MIN_DISTANCE_FOR_FLING = 25; // dips    private static final int MIN_FLING_VELOCITY = 600; // dips    private static final int CLOSE_ENOUGH = 5; // dp    private static final Interpolator sInterpolator = new Interpolator() {        public float getInterpolation(float t) {            t -= 1.0f;            return t * t * t * t * t + 1.0f;        }    };    private static final int INVALID_POINTER = -1;    public static final int SCROLL_STATE_IDLE = 0;    public static final int SCROLL_STATE_DRAGGING = 1;    public static final int SCROLL_STATE_SETTLING = 2;    private static final long LONG_CLICK_DURATION = 500; // ms    private static final long ANIMATION_DURATION = 150; // ms    private static final int EDGE_LFET = 0;    private static final int EDGE_RIGHT = 1;    private static final long EDGE_HOLD_DURATION = 1200; // ms    private int mColCount = DEFAULT_COL_COUNT;    private int mRowCount = DEFAULT_ROW_COUNT;    private int mPageSize = mColCount * mRowCount;    private int mGridGap;    private int mPageCount;    private int mGridWidth;    private int mGridHeight;    private int mMaxOverScrollSize;    private int mEdgeSize;    // internal paddings    private int mPaddingLeft;    private int mPaddingTop;    private int mPaddingRight;    private int mPaddingButtom;    private int mCurItem; // Index of currently displayed page.    private Adapter mAdapter;    private final DataSetObserver mDataSetObserver = new DataSetObserver() {        @Override        public void onChanged() {            dataSetChanged();        }        @Override        public void onInvalidated() {            dataSetChanged();        }    };    private Scroller mScroller;    private boolean mScrollingCacheEnabled;    private boolean mIsBeingDragged;    private boolean mIsUnableToDrag;    private int mTouchSlop;    private float mLastMotionX;    private float mLastMotionY;    private float mInitialMotionX;    private float mInitialMotionY;    private int mActivePointerId = INVALID_POINTER;    private VelocityTracker mVelocityTracker;    private int mMinimumVelocity;    private int mMaximumVelocity;    private int mFlingDistance;    private int mCloseEnough;    // click & long click    private int mLastPosition = -1;    private long mLastDownTime = Long.MAX_VALUE;    // rearrange    private int mLastDragged = -1;    private int mLastTarget = -1;    // edge holding    private int mLastEdge = -1;    private long mLastEdgeTime = Long.MAX_VALUE;    private ArrayList<Integer> newPositions = new ArrayList<Integer>();    private boolean mCalledSuper;    private OnPageChangeListener mOnPageChangeListener;    private OnItemClickListener mOnItemClickListener;    private OnItemLongClickListener mOnItemLongClickListener;    private OnRearrangeListener mOnRearrangeListener;    private final Runnable mEndScrollRunnable = new Runnable() {        public void run() {            setScrollState(SCROLL_STATE_IDLE);        }    };    private int mScrollState = SCROLL_STATE_IDLE;    /**     * Callback interface for responding to changing state of the selected page.     */    public interface OnPageChangeListener {        /**         * This method will be invoked when the current page is scrolled, either as part of a programmatically initiated         * smooth scroll or a user initiated touch scroll.         *          * @param position         *            Position index of the first page currently being displayed. Page position+1 will be visible if         *            positionOffset is nonzero.         * @param positionOffset         *            Value from [0, 1) indicating the offset from the page at position.         * @param positionOffsetPixels         *            Value in pixels indicating the offset from position.         */        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels);        /**         * This method will be invoked when a new page becomes selected. Animation is not necessarily complete.         *          * @param position         *            Position index of the new selected page.         */        public void onPageSelected(int position);        /**         * Called when the scroll state changes. Useful for discovering when the user begins dragging, when the pager is         * automatically settling to the current page, or when it is fully stopped/idle.         *          * @param state         *            The new scroll state.         * @see DraggableGridViewPager#SCROLL_STATE_IDLE         * @see DraggableGridViewPager#SCROLL_STATE_DRAGGING         * @see DraggableGridViewPager#SCROLL_STATE_SETTLING         */        public void onPageScrollStateChanged(int state);    }    /**     * Simple implementation of the {@link OnPageChangeListener} interface with stub implementations of each method.     * Extend this if you do not intend to override every method of {@link OnPageChangeListener}.     */    public static class SimpleOnPageChangeListener implements OnPageChangeListener {        @Override        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {            // This space for rent        }        @Override        public void onPageSelected(int position) {            // This space for rent        }        @Override        public void onPageScrollStateChanged(int state) {            // This space for rent        }    }    public interface OnRearrangeListener {        public abstract void onRearrange(int oldIndex, int newIndex);    }    public DraggableGridViewPager(Context context) {        super(context);        initDraggableGridViewPager();    }    public DraggableGridViewPager(Context context, AttributeSet attrs) {        super(context, attrs);        initDraggableGridViewPager();    }    public DraggableGridViewPager(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        initDraggableGridViewPager();    }    private void initDraggableGridViewPager() {        setWillNotDraw(false);        setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);        setFocusable(true);        setChildrenDrawingOrderEnabled(true);        final Context context = getContext();        final ViewConfiguration configuration = ViewConfiguration.get(context);        final float density = context.getResources().getDisplayMetrics().density;        mGridGap = (int) (DEFAULT_GRID_GAP * density);        // internal paddings        mPaddingLeft = getPaddingLeft();        mPaddingTop = getPaddingTop();        mPaddingRight = getPaddingRight();        mPaddingButtom = getPaddingBottom();        super.setPadding(0, 0, 0, 0);        mScroller = new Scroller(context, sInterpolator);        mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);        mMinimumVelocity = (int) (MIN_FLING_VELOCITY * density);        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();        mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);        mCloseEnough = (int) (CLOSE_ENOUGH * density);    }    @Override    protected void onDetachedFromWindow() {        removeCallbacks(mEndScrollRunnable);        if (mAdapter != null) {            mAdapter.unregisterDataSetObserver(mDataSetObserver);        }        super.onDetachedFromWindow();    }    public int getColCount() {        return mColCount;    }    public void setColCount(int colCount) {        if (colCount < 1) {            colCount = 1;        }        mColCount = colCount;        mPageSize = mColCount * mRowCount;        requestLayout();    }    public int getRowCount() {        return mRowCount;    }    public void setRowCount(int rowCount) {        if (rowCount < 1) {            rowCount = 1;        }        mRowCount = rowCount;        mPageSize = mColCount * mRowCount;        requestLayout();    }    public int getGridGap() {        return mGridGap;    }    public void setGridGap(int gridGap) {        if (gridGap < 0) {            gridGap = 0;        }        mGridGap = gridGap;        requestLayout();    }    public int getPageCount() {        return (getChildCount() + mPageSize - 1) / mPageSize;    }    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        final int childCount = getChildCount();        mPageCount = (childCount + mPageSize - 1) / mPageSize;        //Log.e("stuart","width="+String.valueOf(getWidth()));        mGridWidth = (getWidth() - mPaddingLeft - mPaddingRight - (mColCount - 1) * mGridGap) / mColCount;        //mGridHeight = (getHeight() - mPaddingTop - mPaddingButtom - (mRowCount - 1) * mGridGap) / mRowCount;        mGridWidth = mGridHeight = mGridWidth;        mMaxOverScrollSize = mGridWidth / 2;        mEdgeSize = mGridWidth / 2;        newPositions.clear();        for (int i = 0; i < childCount; i++) {            final View child = getChildAt(i);            final Rect rect = getRectByPosition(i);            child.measure(MeasureSpec.makeMeasureSpec(rect.width(), MeasureSpec.EXACTLY),                    MeasureSpec.makeMeasureSpec(rect.height(), MeasureSpec.EXACTLY));            DEBUG_LOG("child.layout position=" + i + ", rect=" + rect);            child.layout(rect.left, rect.top, rect.right, rect.bottom);            newPositions.add(-1);        }        if (mCurItem > 0 && mCurItem < mPageCount) {            final int curItem = mCurItem;            mCurItem = 0;            setCurrentItem(curItem);        }    }    private void setScrollState(int newState) {        if (mScrollState == newState) {            return;        }        mScrollState = newState;        if (mOnPageChangeListener != null) {            mOnPageChangeListener.onPageScrollStateChanged(newState);        }    }    public int getCurrentItem() {        return mCurItem;    }    public void setCurrentItem(int item) {        setCurrentItemInternal(item, false, false);    }    public void setCurrentItem(int item, boolean smoothScroll) {        setCurrentItemInternal(item, smoothScroll, false);    }    void setCurrentItemInternal(int item, boolean smoothScroll, boolean always) {        setCurrentItemInternal(item, smoothScroll, always, 0);    }    void setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) {        if (mPageCount <= 0) {            setScrollingCacheEnabled(false);            return;        }        if (!always && mCurItem == item) {            setScrollingCacheEnabled(false);            return;        }        if (item < 0) {            item = 0;        } else if (item >= mPageCount) {            item = mPageCount - 1;        }        final boolean dispatchSelected = mCurItem != item;        mCurItem = item;        scrollToItem(item, smoothScroll, velocity, dispatchSelected);    }    private void scrollToItem(int item, boolean smoothScroll, int velocity, boolean dispatchSelected) {        final int destX = getWidth() * item;        if (smoothScroll) {            smoothScrollTo(destX, 0, velocity);            if (dispatchSelected && mOnPageChangeListener != null) {                mOnPageChangeListener.onPageSelected(item);            }        } else {            if (dispatchSelected && mOnPageChangeListener != null) {                mOnPageChangeListener.onPageSelected(item);            }            completeScroll(false);            scrollTo(destX, 0);            pageScrolled(destX);        }    }    public void setOnPageChangeListener(OnPageChangeListener listener) {        mOnPageChangeListener = listener;    }    public void setOnItemClickListener(OnItemClickListener listener) {        mOnItemClickListener = listener;    }    public void setOnItemLongClickListener(OnItemLongClickListener listener) {        mOnItemLongClickListener = listener;    }    public void setOnRearrangeListener(OnRearrangeListener listener) {        mOnRearrangeListener = listener;    }    float distanceInfluenceForSnapDuration(float f) {        f -= 0.5f; // center the values about 0.        f *= 0.3f * Math.PI / 2.0f;        return (float) Math.sin(f);    }    void smoothScrollTo(int x, int y) {        smoothScrollTo(x, y, 0);    }    void smoothScrollTo(int x, int y, int velocity) {        if (getChildCount() == 0) {            // Nothing to do.            setScrollingCacheEnabled(false);            return;        }        int sx = getScrollX();        int sy = getScrollY();        int dx = x - sx;        int dy = y - sy;        if (dx == 0 && dy == 0) {            completeScroll(false);            setScrollState(SCROLL_STATE_IDLE);            return;        }        setScrollingCacheEnabled(true);        setScrollState(SCROLL_STATE_SETTLING);        final int width = getWidth();        final int halfWidth = width / 2;        final float distanceRatio = Math.min(1f, 1.0f * Math.abs(dx) / width);        final float distance = halfWidth + halfWidth *                distanceInfluenceForSnapDuration(distanceRatio);        int duration = 0;        velocity = Math.abs(velocity);        if (velocity > 0) {            duration = 4 * Math.round(1000 * Math.abs(distance / velocity));        } else {            final float pageDelta = (float) Math.abs(dx) / width;            duration = (int) ((pageDelta + 1) * 100);        }        duration = Math.min(duration, MAX_SETTLE_DURATION);        mScroller.startScroll(sx, sy, dx, dy, duration);        ViewCompat.postInvalidateOnAnimation(this);    }    @Override    public void computeScroll() {        if (!mScroller.isFinished() && mScroller.computeScrollOffset()) {            int oldX = getScrollX();            int oldY = getScrollY();            int x = mScroller.getCurrX();            int y = mScroller.getCurrY();            if (oldX != x || oldY != y) {                scrollTo(x, y);                if (!pageScrolled(x)) {                    mScroller.abortAnimation();                    scrollTo(0, y);                }            }            // Keep on drawing until the animation has finished.            ViewCompat.postInvalidateOnAnimation(this);            return;        }        // Done with scroll, clean up state.        completeScroll(true);    }    private boolean pageScrolled(int xpos) {        if (mPageCount <= 0) {            mCalledSuper = false;            onPageScrolled(0, 0, 0);            if (!mCalledSuper) {                throw new IllegalStateException("onPageScrolled did not call superclass implementation");            }            return false;        }        final int width = getWidth();        final int currentPage = xpos / width;        final int offsetPixels = xpos - currentPage * width;        final float pageOffset = (float) offsetPixels / (float) width;        mCalledSuper = false;        onPageScrolled(currentPage, pageOffset, offsetPixels);        if (!mCalledSuper) {            throw new IllegalStateException("onPageScrolled did not call superclass implementation");        }        return true;    }    /**     * This method will be invoked when the current page is scrolled, either as part of a programmatically initiated     * smooth scroll or a user initiated touch scroll. If you override this method you must call through to the     * superclass implementation (e.g. super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled     * returns.     *      * @param position     *            Position index of the first page currently being displayed. Page position+1 will be visible if     *            positionOffset is nonzero.     * @param offset     *            Value from [0, 1) indicating the offset from the page at position.     * @param offsetPixels     *            Value in pixels indicating the offset from position.     */    protected void onPageScrolled(int position, float offset, int offsetPixels) {        if (mOnPageChangeListener != null) {            mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels);        }        mCalledSuper = true;    }    private void completeScroll(boolean postEvents) {        if (mScrollState == SCROLL_STATE_SETTLING) {            // Done with scroll, no longer want to cache view drawing.            setScrollingCacheEnabled(false);            mScroller.abortAnimation();            int oldX = getScrollX();            int oldY = getScrollY();            int x = mScroller.getCurrX();            int y = mScroller.getCurrY();            if (oldX != x || oldY != y) {                scrollTo(x, y);            }            if (postEvents) {                ViewCompat.postOnAnimation(this, mEndScrollRunnable);            } else {                mEndScrollRunnable.run();            }        }    }    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        /*         * This method JUST determines whether we want to intercept the motion. If we return true, onMotionEvent will be         * called and we do the actual scrolling there.         */        final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;        // Always take care of the touch gesture being complete.        if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {            // Release the drag.            DEBUG_LOG("Intercept done!");            mIsBeingDragged = false;            mIsUnableToDrag = false;            mActivePointerId = INVALID_POINTER;            if (mVelocityTracker != null) {                mVelocityTracker.recycle();                mVelocityTracker = null;            }            return false;        }        // Nothing more to do here if we have decided whether or not we        // are dragging.        if (action != MotionEvent.ACTION_DOWN) {            if (mIsBeingDragged || mLastDragged >= 0) {                DEBUG_LOG("Intercept returning true!");                return true;            }            if (mIsUnableToDrag) {                DEBUG_LOG("Intercept returning false!");                return false;            }        }        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. mLastMotionY is set to the y value of the down event.             */            final int activePointerId = mActivePointerId;            if (activePointerId == INVALID_POINTER) {                // If we don't have a valid id, the touch down wasn't on content.                break;            }            final int pointerIndex = MotionEventCompat.findPointerIndex(ev, activePointerId);            final float x = MotionEventCompat.getX(ev, pointerIndex);            final float dx = x - mLastMotionX;            final float xDiff = Math.abs(dx);            final float y = MotionEventCompat.getY(ev, pointerIndex);            final float yDiff = Math.abs(y - mInitialMotionY);            DEBUG_LOG("***Moved to " + x + "," + y + " diff=" + xDiff + "," + yDiff);            if (xDiff > mTouchSlop && xDiff * 0.5f > yDiff) {                DEBUG_LOG("***Starting drag!");                mIsBeingDragged = true;                requestParentDisallowInterceptTouchEvent(true);                setScrollState(SCROLL_STATE_DRAGGING);                mLastMotionX = dx > 0 ? mInitialMotionX + mTouchSlop :                        mInitialMotionX - mTouchSlop;                mLastMotionY = y;                setScrollingCacheEnabled(true);            } else if (yDiff > mTouchSlop) {                // The finger has moved enough in the vertical                // direction to be counted as a drag... abort                // any attempt to drag horizontally, to work correctly                // with children that have scrolling containers.                DEBUG_LOG("***Unable to drag!");                mIsUnableToDrag = true;            }            if (mIsBeingDragged) {                // Scroll to follow the motion event                if (performDrag(x)) {                    ViewCompat.postInvalidateOnAnimation(this);                }            }            break;        }        case MotionEvent.ACTION_DOWN: {            /*             * Remember location of down touch. ACTION_DOWN always refers to pointer index 0.             */            mLastMotionX = mInitialMotionX = ev.getX();            mLastMotionY = mInitialMotionY = ev.getY();            mActivePointerId = MotionEventCompat.getPointerId(ev, 0);            mIsUnableToDrag = false;            mScroller.computeScrollOffset();            if (mScrollState == SCROLL_STATE_SETTLING &&                    Math.abs(mScroller.getFinalX() - mScroller.getCurrX()) > mCloseEnough) {                // Let the user 'catch' the pager as it animates.                mScroller.abortAnimation();                mIsBeingDragged = true;                requestParentDisallowInterceptTouchEvent(true);                setScrollState(SCROLL_STATE_DRAGGING);            } else {                completeScroll(false);                mIsBeingDragged = false;            }            DEBUG_LOG("***Down at " + mLastMotionX + "," + mLastMotionY                    + " mIsBeingDragged=" + mIsBeingDragged                    + " mIsUnableToDrag=" + mIsUnableToDrag);            mLastDragged = -1;            break;        }        case MotionEventCompat.ACTION_POINTER_UP:            onSecondaryPointerUp(ev);            break;        }        if (mVelocityTracker == null) {            mVelocityTracker = VelocityTracker.obtain();        }        mVelocityTracker.addMovement(ev);        /*         * The only time we want to intercept motion events is if we are in the drag mode.         */        return mIsBeingDragged;    }    @Override    public boolean onTouchEvent(MotionEvent ev) {        if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) {            // Don't handle edge touches immediately -- they may actually belong to one of our            // descendants.            return false;        }        if (mPageCount <= 0) {            // Nothing to present or scroll; nothing to touch.            return false;        }        if (mVelocityTracker == null) {            mVelocityTracker = VelocityTracker.obtain();        }        mVelocityTracker.addMovement(ev);        final int action = ev.getAction();        boolean needsInvalidate = false;        switch (action & MotionEventCompat.ACTION_MASK) {        case MotionEvent.ACTION_DOWN: {            mScroller.abortAnimation();            // Remember where the motion event started            mLastMotionX = mInitialMotionX = ev.getX();            mLastMotionY = mInitialMotionY = ev.getY();            mActivePointerId = MotionEventCompat.getPointerId(ev, 0);            DEBUG_LOG("Down at " + mLastMotionX + "," + mLastMotionY                    + " mIsBeingDragged=" + mIsBeingDragged                    + " mIsUnableToDrag=" + mIsUnableToDrag);            if (!mIsBeingDragged && mScrollState == SCROLL_STATE_IDLE) {                mLastPosition = getPositionByXY((int) mLastMotionX, (int) mLastMotionY);            } else {                mLastPosition = -1;            }            if (mLastPosition >= 0) {                mLastDownTime = System.currentTimeMillis();            } else {                mLastDownTime = Long.MAX_VALUE;            }            DEBUG_LOG("Down at mLastPosition=" + mLastPosition);            mLastDragged = -1;            break;        }        case MotionEvent.ACTION_MOVE: {            final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);            final float x = MotionEventCompat.getX(ev, pointerIndex);            final float y = MotionEventCompat.getY(ev, pointerIndex);            if (mLastDragged >= 0) {                // change draw location of dragged visual                final View v = getChildAt(mLastDragged);                final int l = getScrollX() + (int) x - v.getWidth() / 2;                final int t = getScrollY() + (int) y - v.getHeight() / 2;                v.layout(l, t, l + v.getWidth(), t + v.getHeight());                // check for new target hover                if (mScrollState == SCROLL_STATE_IDLE) {                    final int target = getTargetByXY((int) x, (int) y);                    if (target != -1 && mLastTarget != target) {                        animateGap(target);                        mLastTarget = target;                        DEBUG_LOG("Moved to mLastTarget=" + mLastTarget);                    }                    // edge holding                    final int edge = getEdgeByXY((int) x, (int) y);                    if (mLastEdge == -1) {                        if (edge != mLastEdge) {                            mLastEdge = edge;                            mLastEdgeTime = System.currentTimeMillis();                        }                    } else {                        if (edge != mLastEdge) {                            mLastEdge = -1;                        } else {                            if ((System.currentTimeMillis() - mLastEdgeTime) >= EDGE_HOLD_DURATION) {                                performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);                                triggerSwipe(edge);                                mLastEdge = -1;                            }                        }                    }                }            } else if (!mIsBeingDragged) {                final float xDiff = Math.abs(x - mLastMotionX);                final float yDiff = Math.abs(y - mLastMotionY);                DEBUG_LOG("Moved to " + x + "," + y + " diff=" + xDiff + "," + yDiff);                if (xDiff > mTouchSlop && xDiff > yDiff) {                    DEBUG_LOG("Starting drag!");                    mIsBeingDragged = true;                    requestParentDisallowInterceptTouchEvent(true);                    mLastMotionX = x - mInitialMotionX > 0 ? mInitialMotionX + mTouchSlop :                            mInitialMotionX - mTouchSlop;                    mLastMotionY = y;                    setScrollState(SCROLL_STATE_DRAGGING);                    setScrollingCacheEnabled(true);                }            }            // Not else! Note that mIsBeingDragged can be set above.            if (mIsBeingDragged) {                // Scroll to follow the motion event                needsInvalidate |= performDrag(x);            } else if (mLastPosition >= 0) {                final int currentPosition = getPositionByXY((int) x, (int) y);                DEBUG_LOG("Moved to currentPosition=" + currentPosition);                if (currentPosition == mLastPosition) {                    if ((System.currentTimeMillis() - mLastDownTime) >= LONG_CLICK_DURATION) {                        if (onItemLongClick(currentPosition)) {                            performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);                            mLastDragged = mLastPosition;                            requestParentDisallowInterceptTouchEvent(true);                            mLastTarget = -1;                            animateDragged();                            mLastPosition = -1;                        }                        mLastDownTime = Long.MAX_VALUE;                    }                } else {                    mLastPosition = -1;                }            }            break;        }        case MotionEvent.ACTION_UP: {            DEBUG_LOG("Touch up!!!");            final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);            final float x = MotionEventCompat.getX(ev, pointerIndex);            final float y = MotionEventCompat.getY(ev, pointerIndex);            if (mLastDragged >= 0) {                rearrange();            } else if (mIsBeingDragged) {                final VelocityTracker velocityTracker = mVelocityTracker;                velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);                int initialVelocity = (int) VelocityTrackerCompat.getXVelocity(velocityTracker, mActivePointerId);                final int width = getWidth();                final int scrollX = getScrollX();                final int currentPage = scrollX / width;                final int offsetPixels = scrollX - currentPage * width;                final float pageOffset = (float) offsetPixels / (float) width;                final int totalDelta = (int) (x - mInitialMotionX);                int nextPage = determineTargetPage(currentPage, pageOffset, initialVelocity, totalDelta);                setCurrentItemInternal(nextPage, true, true, initialVelocity);                mActivePointerId = INVALID_POINTER;                endDrag();            } else if (mLastPosition >= 0) {                final int currentPosition = getPositionByXY((int) x, (int) y);                DEBUG_LOG("Touch up!!! currentPosition=" + currentPosition);                if (currentPosition == mLastPosition) {                    onItemClick(currentPosition);                }            }            break;        }        case MotionEvent.ACTION_CANCEL:            DEBUG_LOG("Touch cancel!!!");            if (mLastDragged >= 0) {                rearrange();            } else if (mIsBeingDragged) {                scrollToItem(mCurItem, true, 0, false);                mActivePointerId = INVALID_POINTER;                endDrag();            }            break;        case MotionEventCompat.ACTION_POINTER_DOWN: {            final int index = MotionEventCompat.getActionIndex(ev);            final float x = MotionEventCompat.getX(ev, index);            mLastMotionX = x;            mActivePointerId = MotionEventCompat.getPointerId(ev, index);            break;        }        case MotionEventCompat.ACTION_POINTER_UP:            onSecondaryPointerUp(ev);            mLastMotionX = MotionEventCompat.getX(ev,                    MotionEventCompat.findPointerIndex(ev, mActivePointerId));            break;        }        if (needsInvalidate) {            ViewCompat.postInvalidateOnAnimation(this);        }        return true;    }    private void requestParentDisallowInterceptTouchEvent(boolean disallowIntercept) {        final ViewParent parent = getParent();        if (parent != null) {            parent.getParent().requestDisallowInterceptTouchEvent(disallowIntercept);        }    }    private boolean performDrag(float x) {        boolean needsInvalidate = false;        final float deltaX = mLastMotionX - x;        mLastMotionX = x;        float oldScrollX = getScrollX();        float scrollX = oldScrollX + deltaX;        final int width = getWidth();        float leftBound = width * 0;        float rightBound = width * (mPageCount - 1);        if (scrollX < leftBound) {            final float over = Math.min(leftBound - scrollX, mMaxOverScrollSize);            scrollX = leftBound - over;        } else if (scrollX > rightBound) {            final float over = Math.min(scrollX - rightBound, mMaxOverScrollSize);            scrollX = rightBound + over;        }        // Don't lose the rounded component        mLastMotionX += scrollX - (int) scrollX;        scrollTo((int) scrollX, getScrollY());        pageScrolled((int) scrollX);        return needsInvalidate;    }    private int determineTargetPage(int currentPage, float pageOffset, int velocity, int deltaX) {        int targetPage;        if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) {            targetPage = velocity > 0 ? currentPage : currentPage + 1;        } else {            final float truncator = currentPage >= mCurItem ? 0.4f : 0.6f;            targetPage = (int) (currentPage + pageOffset + truncator);        }        return targetPage;    }    private void onSecondaryPointerUp(MotionEvent ev) {        final int pointerIndex = MotionEventCompat.getActionIndex(ev);        final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);        if (pointerId == mActivePointerId) {            // This was our active pointer going up. Choose a new            // active pointer and adjust accordingly.            final int newPointerIndex = pointerIndex == 0 ? 1 : 0;            mLastMotionX = MotionEventCompat.getX(ev, newPointerIndex);            mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);            if (mVelocityTracker != null) {                mVelocityTracker.clear();            }        }    }    private void endDrag() {        mIsBeingDragged = false;        mIsUnableToDrag = false;        if (mVelocityTracker != null) {            mVelocityTracker.recycle();            mVelocityTracker = null;        }    }    private void setScrollingCacheEnabled(boolean enabled) {        if (mScrollingCacheEnabled != enabled) {            mScrollingCacheEnabled = enabled;            if (USE_CACHE) {                final int size = getChildCount();                for (int i = 0; i < size; ++i) {                    final View child = getChildAt(i);                    if (child.getVisibility() != GONE) {                        child.setDrawingCacheEnabled(enabled);                    }                }            }        }    }    private void dataSetChanged() {        DEBUG_LOG("dataSetChanged");        for (int i = 0; i < getChildCount() && i < mAdapter.getCount(); i++) {            final View child = getChildAt(i);            final View newChild = mAdapter.getView(i, child, this);            if (newChild != child) {                removeViewAt(i);                addView(newChild, i);            }        }        for (int i = getChildCount(); i < mAdapter.getCount(); i++) {            final View child = mAdapter.getView(i, null, this);            addView(child);        }        while (getChildCount() > mAdapter.getCount()) {            removeViewAt(getChildCount() - 1);        }    }    public void setAdapter(Adapter adapter) {        if (mAdapter != null) {            mAdapter.unregisterDataSetObserver(mDataSetObserver);            removeAllViews();            mCurItem = 0;            scrollTo(0, 0);        }        mAdapter = adapter;        if (mAdapter != null) {            mAdapter.registerDataSetObserver(mDataSetObserver);            for (int i = 0; i < mAdapter.getCount(); i++) {                final View child = mAdapter.getView(i, null, this);                addView(child);            }        }    }    private Rect getRectByPosition(int position) {        final int page = position / mPageSize;        final int col = (position % mPageSize) % mColCount;        final int row = (position % mPageSize) / mColCount;        final int left = getWidth() * page + mPaddingLeft + col * (mGridWidth + mGridGap);        final int top = mPaddingTop + row * (mGridHeight + mGridGap);        return new Rect(left, top, left + mGridWidth, top + mGridHeight);    }    private int getPositionByXY(int x, int y) {        final int col = (x - mPaddingLeft) / (mGridWidth + mGridGap);        final int row = (y - mPaddingTop) / (mGridHeight + mGridGap);        if (x < mPaddingLeft || x >= (mPaddingLeft + col * (mGridWidth + mGridGap) + mGridWidth) ||                y < mPaddingTop || y >= (mPaddingTop + row * (mGridHeight + mGridGap) + mGridHeight) ||                col < 0 || col >= mColCount ||                row < 0 || row >= mRowCount) {            // touch in padding            return -1;        }        final int position = mCurItem * mPageSize + row * mColCount + col;        if (position < 0 || position >= getChildCount()) {            // empty item            return -1;        }        return position;    }    private int getTargetByXY(int x, int y) {        final int position = getPositionByXY(x, y);        if (position < 0) {            return -1;        }        final Rect r = getRectByPosition(position);        final int page = position / mPageSize;        r.inset(r.width() / 4, r.height() / 4);        r.offset(-getWidth() * page, 0);        if (!r.contains(x, y)) {            return -1;        }        return position;    }    private void onItemClick(int position) {        DEBUG_LOG("onItemClick position=" + position);        if (mOnItemClickListener != null) {            mOnItemClickListener.onItemClick(null, getChildAt(position), position, position / mColCount);        }    }    private boolean onItemLongClick(int position) {        DEBUG_LOG("onItemLongClick position=" + position);        if (mOnItemLongClickListener != null) {            if(ICBCButtonAdapter.canDrag) {                if (position != 4) {                    int realposition=position>3?(position-1):position;                    return mOnItemLongClickListener.onItemLongClick(null, getChildAt(realposition), realposition, realposition / mColCount);                }            }        }        return false;    }    @Override    protected int getChildDrawingOrder(int childCount, int i) {        if (mLastDragged == -1) {            return i;        } else if (i == childCount - 1) {            return mLastDragged;        } else if (i >= mLastDragged) {            return i + 1;        }        return i;    }    private void animateDragged() {        if (mLastDragged >= 0) {            final View v = getChildAt(mLastDragged);            final Rect r = new Rect(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());            r.inset(-r.width() / 20, -r.height() / 20);            v.measure(MeasureSpec.makeMeasureSpec(r.width(), MeasureSpec.EXACTLY),                    MeasureSpec.makeMeasureSpec(r.height(), MeasureSpec.EXACTLY));            v.layout(r.left, r.top, r.right, r.bottom);            AnimationSet animSet = new AnimationSet(true);            ScaleAnimation scale = new ScaleAnimation(0.9091f, 1, 0.9091f, 1, v.getWidth() / 2, v.getHeight() / 2);            scale.setDuration(ANIMATION_DURATION);            AlphaAnimation alpha = new AlphaAnimation(1, .5f);            alpha.setDuration(ANIMATION_DURATION);            animSet.addAnimation(scale);            animSet.addAnimation(alpha);            animSet.setFillEnabled(true);            animSet.setFillAfter(true);            v.clearAnimation();            v.startAnimation(animSet);        }    }    private void animateGap(int target) {        for (int i = 0; i < getChildCount(); i++) {            View v = getChildAt(i);            if (i == mLastDragged) {                continue;            }            int newPos = i;            if (mLastDragged < target && i >= mLastDragged + 1 && i <= target) {                if(newPos==4){                    continue;                }                newPos--;                if(newPos==4){                    newPos--;                }            } else if (target < mLastDragged && i >= target && i < mLastDragged) {            //  Log.e("stuart drag","target="+String.valueOf(target)+" mLastDragged="+String.valueOf(mLastDragged)+" newPos="+String.valueOf(newPos));                newPos++;                if(newPos==5){                    continue;                }                if(newPos==4){                    newPos++;                }            }            int oldPos = i;            if (newPositions.get(i) != -1) {                oldPos = newPositions.get(i);            }            if (oldPos == newPos) {                continue;            }            // animate            DEBUG_LOG("animateGap from=" + oldPos + ", to=" + newPos);            final Rect oldRect = getRectByPosition(oldPos);            final Rect newRect = getRectByPosition(newPos);            oldRect.offset(-v.getLeft(), -v.getTop());            newRect.offset(-v.getLeft(), -v.getTop());            TranslateAnimation translate = new TranslateAnimation(                    oldRect.left, newRect.left,                    oldRect.top, newRect.top);            translate.setDuration(ANIMATION_DURATION);            translate.setFillEnabled(true);            translate.setFillAfter(true);            v.clearAnimation();            v.startAnimation(translate);            newPositions.set(i, newPos);        }    }    private void rearrange() {        if (mLastDragged >= 0) {            for (int i = 0; i < getChildCount(); i++) {                getChildAt(i).clearAnimation();            }            if (mLastTarget >= 0 && mLastDragged != mLastTarget) {                final View child = getChildAt(mLastDragged);                removeViewAt(mLastDragged);                addView(child, mLastTarget);                if (mOnRearrangeListener != null) {                    mOnRearrangeListener.onRearrange(mLastDragged, mLastTarget);                }            }            mLastDragged = -1;            mLastTarget = -1;            requestLayout();            invalidate();        }    }    private int getEdgeByXY(int x, int y) {        if (x < mEdgeSize) {            return EDGE_LFET;        } else if (x >= (getWidth() - mEdgeSize)) {            return EDGE_RIGHT;        }        return -1;    }    private void triggerSwipe(int edge) {        if (edge == EDGE_LFET && mCurItem > 0) {            setCurrentItem(mCurItem - 1, true);        } else if (edge == EDGE_RIGHT && mCurItem < mPageCount - 1) {            setCurrentItem(mCurItem + 1, true);        }    }    @Override    public void onRestoreInstanceState(Parcelable state) {        SavedState savedState = (SavedState) state;        super.onRestoreInstanceState(savedState.getSuperState());        mCurItem = savedState.curItem;        requestLayout();    }    @Override    public Parcelable onSaveInstanceState() {        Parcelable superState = super.onSaveInstanceState();        SavedState savedState = new SavedState(superState);        savedState.curItem = mCurItem;        return savedState;    }    static class SavedState extends BaseSavedState {        int curItem;        public SavedState(Parcelable superState) {            super(superState);        }        private SavedState(Parcel in) {            super(in);            curItem = in.readInt();        }        @Override        public void writeToParcel(Parcel dest, int flags) {            super.writeToParcel(dest, flags);            dest.writeInt(curItem);        }        @SuppressWarnings("UnusedDeclaration")        public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {            @Override            public SavedState createFromParcel(Parcel in) {                return new SavedState(in);            }            @Override            public SavedState[] newArray(int size) {                return new SavedState[size];            }        };    }}

这是我改完之后的view类，感谢这位大神使用了viewgroup写了如此之详细的类。

private void animateGap(int target) {        for (int i = 0; i < getChildCount(); i++) {            View v = getChildAt(i);            if (i == mLastDragged) {                continue;            }            int newPos = i;            if (mLastDragged < target && i >= mLastDragged + 1 && i <= target) {                if(newPos==4){                    continue;                }                newPos--;                if(newPos==4){                    newPos--;                }            } else if (target < mLastDragged && i >= target && i < mLastDragged) {            //  Log.e("stuart drag","target="+String.valueOf(target)+" mLastDragged="+String.valueOf(mLastDragged)+" newPos="+String.valueOf(newPos));                newPos++;                if(newPos==5){                    continue;                }                if(newPos==4){                    newPos++;                }            }            int oldPos = i;            if (newPositions.get(i) != -1) {                oldPos = newPositions.get(i);            }            if (oldPos == newPos) {                continue;            }            // animate            DEBUG_LOG("animateGap from=" + oldPos + ", to=" + newPos);            final Rect oldRect = getRectByPosition(oldPos);            final Rect newRect = getRectByPosition(newPos);            oldRect.offset(-v.getLeft(), -v.getTop());            newRect.offset(-v.getLeft(), -v.getTop());            TranslateAnimation translate = new TranslateAnimation(                    oldRect.left, newRect.left,                    oldRect.top, newRect.top);            translate.setDuration(ANIMATION_DURATION);            translate.setFillEnabled(true);            translate.setFillAfter(true);            v.clearAnimation();            v.startAnimation(translate);            newPositions.set(i, newPos);        }    }

这个函数是改变的最关键的地方。从逻辑上来讲，就是item从左向右移动的时候遇到第4个直接跳到下一行第一个即第六个的位置，因为第五个是更多。同理，item从右向左移动的时候遇到第六个就直接跳到上一行的倒数第二个即第四个位置，因为第五个是更多。

从工程的角度来讲，这个只是在逻辑上实现了基础功能。而实际上，从网络端获取的只有一个一个的按钮信息。对于一个合作开发的团队来说，你怎么可能写了一个自定义view还要告诉他记得第五个加上更多按钮，获取adapter里的list的时候记得把更多按钮删除。这样不被打几乎是不可能的。

然后就需要在adapter里动一点手脚了。下面就是我改完之后的adapter：

package com.kting.baijinka.adapter;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ImageView;import android.widget.TextView;import com.kting.baijinka.R;import com.kting.baijinka.net.response.ICBCButtonResponseBean;import com.nostra13.universalimageloader.core.ImageLoader;import java.util.ArrayList;import java.util.List;/** * Created by Administrator on 2016/4/20. */public class ICBCButtonAdapter extends ArrayAdapter {    private List<ICBCButtonResponseBean> originlist=new ArrayList<>();    private List<ICBCButtonResponseBean> realList=new ArrayList<>();    List<ICBCButtonResponseBean> contentList=new ArrayList<>();    private Context mContext;    private LayoutInflater inflater;    private ImageView iv;    private TextView tv;    private int resourceid;    private boolean isFirstTime=true;    public static boolean canDrag=false;    public ICBCButtonAdapter(Context mContext, List<ICBCButtonResponseBean> list,int resourceid){        super(mContext,resourceid);        this.originlist.clear();        originlist.addAll(list);        this.mContext=mContext;        this.resourceid=resourceid;        inflater = LayoutInflater.from(mContext);        hideItems();    }    @Override    public int getCount() {        return realList.size();    }    @Override    public ICBCButtonResponseBean getItem(int position) {        return realList.get(position);    }    @Override    public long getItemId(int position) {        return 0;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        final String text = realList.get(position).getButtonTitle();        final String pic = realList.get(position).getButtonPic();        if (convertView == null) {            convertView = inflater.inflate(resourceid, null);        }        iv=(ImageView)convertView.findViewById(                R.id.iv_icbc_button);        tv=(TextView)convertView.findViewById(R.id.tv_icbc_button);        if (position != 4) {            ImageLoader.getInstance().displayImage(pic, iv);            tv.setText(text);        } else {            tv.setText("更多");            if (canDrag) {                iv.setImageResource(R.drawable.retract);            } else {                iv.setImageResource(R.drawable.more);            }        }        return convertView;    }    public void swapItem(int oldIndex,int newIndex){        ICBCButtonResponseBean itemMore = realList.get(4);        ICBCButtonResponseBean item = realList.get(oldIndex);        realList.remove(item);        realList.add(newIndex,item);        realList.remove(itemMore);        realList.add(4,itemMore);        contentList.clear();        contentList.addAll(realList);        contentList.remove(contentList.get(4));    }    public void hideItems(){        canDrag=false;        if(isFirstTime) {            realList.clear();            for (int i = 0; i < 4; i++) {                realList.add(originlist.get(i));            }            ICBCButtonResponseBean ib = new ICBCButtonResponseBean();            realList.add(ib);            contentList.clear();            contentList.addAll(originlist);            notifyDataSetChanged();            isFirstTime=false;        }else{            realList.clear();            for (int i = 0; i < 4; i++) {                realList.add(contentList.get(i));            }            ICBCButtonResponseBean ib = new ICBCButtonResponseBean();            realList.add(ib);            notifyDataSetChanged();        }    }    public void showItems(){        canDrag=true;        realList.clear();        realList.addAll(contentList);        ICBCButtonResponseBean ib=new ICBCButtonResponseBean();        realList.add(4,ib);        notifyDataSetChanged();    }    public List<ICBCButtonResponseBean> getContentList(){        return contentList;    }    public boolean canDraggable(){        return canDrag;    }    public void reLoadList(List<ICBCButtonResponseBean> list){        this.originlist.clear();        originlist.addAll(list);        isFirstTime=true;        hideItems();    }}

这里涉及到了三个list，originlist、reallist、contentlist。
从外部赋值给adapter的是originlist，我再将更多按钮放到列表的第五个位置，这就成了reallist，reallist才是真正运行自定义view的数据。当activity需要调用内部数据的时候（重新排序的）就需要getcontentlist。至于他究竟需要拿这些数据干嘛就不管我的事了。
不管怎么说放个图还是有必要的。

demo放在了oschina上，有兴趣可以去看看：http://git.oschina.net/stuartPounds/draggedView