android view实现横向滑动选择

  public boolean mAlwaysOverrideTouch = true;
  protected ListAdapter mAdapter;
  private int mLeftViewIndex = -1;
  private int mRightViewIndex = 0;
  protected int mCurrentX;
  protected int mNextX;
  private int mMaxX = Integer.MAX_VALUE;
  private int mDisplayOffset = 0;
  protected Scroller mScroller;
  private GestureDetector mGesture;
  private Queue<View> mRemovedViewQueue = new LinkedList<View>();
  private OnItemSelectedListener mOnItemSelected;
  private OnItemClickListener mOnItemClicked;
  private OnItemLongClickListener mOnItemLongClicked;
  private OnScrollListener mScrollListener;
  /**
   * 选中item时图片
   */
  private Drawable mDrawable;
  private boolean mDataChanged = false;
  private Context context;
  private boolean scrollerFalg1 = false;
  private boolean scrollerFalg2 = false;
  private int position = 0x7f020000;
 
 
  public HorizontalScrollSelectView(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.context = context;
    initView();
  }
 
  private synchronized void initView() {
    mLeftViewIndex = -1;
    mRightViewIndex = 0;
    mDisplayOffset = 0;
    mCurrentX = 0;
    mNextX = 0;
    mMaxX = Integer.MAX_VALUE;
    mScroller = new Scroller(getContext());
    mGesture = new GestureDetector(getContext(), mOnGesture);
  }
 
  public void setMScrollListener(OnScrollListener listener) {
    mScrollListener = listener;
  }
 
  @Override
  public void setOnItemSelectedListener(OnItemSelectedListener listener) {
    mOnItemSelected = listener;
  }
 
  @Override
  public void setOnItemClickListener(OnItemClickListener listener) {
    mOnItemClicked = listener;
  }
 
  @Override
  public void setOnItemLongClickListener(OnItemLongClickListener listener) {
    mOnItemLongClicked = listener;
  }
 
  /**
   * 设置选中状态时的图片
   *
   * @param mDrawable
   */
  public void setSelectBitmap(Drawable mDrawable) {
    this.mDrawable = mDrawable;
  }
 
  private DataSetObserver mDataObserver = new DataSetObserver() {
 
    @Override
    public void onChanged() {
      synchronized (HorizontalScrollSelectView.this) {
        mDataChanged = true;
      }
      invalidate();
      requestLayout();
    }
 
    @Override
    public void onInvalidated() {
      reset();
      invalidate();
      requestLayout();
    }
 
  };
 
  @Override
  public ListAdapter getAdapter() {
    return mAdapter;
  }
 
  @Override
  public View getSelectedView() {
    //TODO: implement
    return null;
  }
 
  @Override
  public void setAdapter(ListAdapter adapter) {
    if (mAdapter != null) {
      mAdapter.unregisterDataSetObserver(mDataObserver);
    }
    mAdapter = adapter;
    mAdapter.registerDataSetObserver(mDataObserver);
    reset();
  }
 
  private synchronized void reset() {
    initView();
    removeAllViewsInLayout();
    requestLayout();
  }
 
  @Override
  public void setSelection(int position) {
    //TODO: implement
    int positionX = position * this.getWidth();
    int maxWidth = this.getChildCount() * this.getWidth();
    if (positionX <= 0) {
      positionX = 0;
    }
    if (positionX > maxWidth) {
      positionX = maxWidth;
    }
    scrollTo(positionX);
  }
 
  private void addAndMeasureChild(final View child, int viewPos) {
    LayoutParams params = child.getLayoutParams();
    if (params == null) {
      params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
    }
 
    addViewInLayout(child, viewPos, params, true);
    child.measure(MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.AT_MOST),
        MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.AT_MOST));
  }
 
 
  @SuppressLint("NewApi")
  @Override
  protected synchronized void onLayout(boolean changed, int left, int top, int right, int bottom) {
    super.onLayout(changed, left, top, right, bottom);
 
    if (mAdapter == null) {
      return;
    }
 
    if (mDataChanged) {
      int oldCurrentX = mCurrentX;
      initView();
      removeAllViewsInLayout();
      mNextX = oldCurrentX;
      mDataChanged = false;
    }
 
    if (mScroller.computeScrollOffset()) {
      int scrollx = mScroller.getCurrX();
      mNextX = scrollx;
    }
 
// if(mNextX <= 0){
//  mNextX = 0;
//  mScroller.forceFinished(true);
// }
// if(mNextX >= mMaxX) {
//  mNextX = mMaxX;
//  mScroller.forceFinished(true);
// }
 
    int dx = mCurrentX - mNextX;
 
    removeNonVisibleItems(dx);
    fillList(dx);
    positionItems(dx);
// Log.e("onlayout", "mLeftViewIndex"+(mLeftViewIndex+1));
    mCurrentX = mNextX;
 
    if (!mScroller.isFinished()) {
      post(new Runnable() {
        @Override
        public void run() {
          requestLayout();
        }
      });
 
    } else {
      if (scrollerFalg1 || (!scrollerFalg1 && scrollerFalg2)) {
        View chid = getChildAt(0);
        if (chid != null) {
          mDisplayOffset = 0;
          positionItems(0);
          if (mDrawable != null) {
            getChildAt(2).setBackground(mDrawable);
          }
          if (mScrollListener != null) {
            int position = (int) getChildAt(2).getTag(this.position);
            mScrollListener.onScrollSelectItem(this, position);
          }
        }
 
      }
    }
 
 
  }
 
  /**
   * 获取屏幕宽度
   *
   * @param context
   * @return
   */
  public static int getSecreenWidth(Context context) {
    DisplayMetrics dm = new DisplayMetrics();
    dm = context.getResources().getDisplayMetrics();
    int screenWidth = dm.widthPixels;
    return screenWidth / 5;
  }
 
  private void fillList(final int dx) {
    int edge = 0;
    View child = getChildAt(0);
    if (child != null) {
      edge = child.getLeft();
    }
    fillListLeft(edge, dx);
 
    edge = 0;
    child = getChildAt(getChildCount() - 1);
    if (child != null) {
      edge = child.getRight();
    }
    fillListRight(edge, dx);
 
  }
 
  private void fillListRight(int rightEdge, final int dx) {
    //&& mRightViewIndex < mAdapter.getCount()
    while (rightEdge + dx < getWidth()) {
      if (mRightViewIndex >= mAdapter.getCount()) {
        mRightViewIndex = 0;
      }
      View child = mAdapter.getView(mRightViewIndex, mRemovedViewQueue.poll(), this);
      child.setTag(position, mRightViewIndex);
      addAndMeasureChild(child, -1);
      rightEdge += child.getMeasuredWidth();
 
//  if(mRightViewIndex == mAdapter.getCount()-1) {
//  mMaxX = mCurrentX + rightEdge - getWidth();
//  }
//  
//  if (mMaxX < 0) {
//  mMaxX = 0;
//  }
      mRightViewIndex++;
    }
 
  }
 
  private void fillListLeft(int leftEdge, final int dx) {
    //&& mLeftViewIndex >= 0
    while (leftEdge + dx > 0) {
      if (mLeftViewIndex <= -1) {
        mLeftViewIndex = mAdapter.getCount() - 1;
      }
      View child = mAdapter.getView(mLeftViewIndex, mRemovedViewQueue.poll(), this);
      child.setTag(position, mLeftViewIndex);
      addAndMeasureChild(child, 0);
      leftEdge -= child.getMeasuredWidth();
      mLeftViewIndex--;
      mDisplayOffset -= child.getMeasuredWidth();
    }
  }
 
  private void removeNonVisibleItems(final int dx) {
    View child = getChildAt(0);
    while (child != null && child.getRight() + dx <= 0) {
      mDisplayOffset += child.getMeasuredWidth();
      mRemovedViewQueue.offer(child);
      removeViewInLayout(child);
      mLeftViewIndex++;
      if (mLeftViewIndex >= mAdapter.getCount()) {
        mLeftViewIndex = 0;
      }
      child = getChildAt(0);
 
    }
 
    child = getChildAt(getChildCount() - 1);
    while (child != null && child.getLeft() + dx >= getWidth()) {
      mRemovedViewQueue.offer(child);
      removeViewInLayout(child);
      mRightViewIndex--;
      if (mRightViewIndex <= -1) {
        mRightViewIndex = mAdapter.getCount() - 1;
      }
      child = getChildAt(getChildCount() - 1);
    }
  }
 
 
  private void positionItems(final int dx) {
    if (getChildCount() > 0) {
      mDisplayOffset += dx;
      int left = mDisplayOffset;
      for (int i = 0; i < getChildCount(); i++) {
        View child = getChildAt(i);
        getChildAt(2).setBackground(null);
        int childWidth = child.getMeasuredWidth();
        child.layout(left, 0, left + childWidth, child.getMeasuredHeight());
        left += childWidth + child.getPaddingRight();
      }
    }
  }
 
  public synchronized void scrollTo(int x) {
    mScroller.startScroll(mNextX, 0, x - mNextX, 0);
    requestLayout();
  }
 
  @Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
    boolean handled = super.dispatchTouchEvent(ev);
    handled |= mGesture.onTouchEvent(ev);
 
    switch (ev.getAction()) {
      case MotionEvent.ACTION_UP:
        scrollerFalg2 = true;
        requestLayout();
        break;
      default:
        break;
    }
    return handled;
  }
 
  protected boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
               float velocityY) {
    synchronized (HorizontalScrollSelectView.this) {
      //mNextX
      mScroller.fling(mNextX, 0, (int) -velocityX, 0, Integer.MIN_VALUE, mMaxX, 0, 0);
    }
    requestLayout();
    scrollerFalg1 = true;
    return true;
  }
 
  protected boolean onDown(MotionEvent e) {
    mScroller.forceFinished(true);
    return true;
  }
 
  public interface OnScrollListener {
    /**
     * 互动过程中选中的item
     *
     * @param position
     */
    public void onScrollSelectItem(ViewGroup viewGroup, int position);
 
  }
 
 
  private OnGestureListener mOnGesture = new GestureDetector.SimpleOnGestureListener() {
 
    @Override
    public boolean onDown(MotionEvent e) {
      return HorizontalScrollSelectView.this.onDown(e);
    }
 
    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                float velocityY) {
      return HorizontalScrollSelectView.this.onFling(e1, e2, velocityX, velocityY);
    }
 
    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2,
                float distanceX, float distanceY) {
 
      synchronized (HorizontalScrollSelectView.this) {
        mNextX += (int) distanceX;
      }
      requestLayout();
      scrollerFalg1 = false;
      scrollerFalg2 = false;
      return true;
    }
 
 
    @Override
    public void onShowPress(MotionEvent e) {
      super.onShowPress(e);
    }
 
    @Override
    public boolean onSingleTapUp(MotionEvent e) {
      Log.e("onSingleTapUp", "mLeftViewIndex" + (mLeftViewIndex + 1));
//  scrollerFalg=true;
      return super.onSingleTapUp(e);
    }
 
    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
      for (int i = 0; i < getChildCount(); i++) {
        View child = getChildAt(i);
        if (isEventWithinView(e, child)) {
          if (mOnItemClicked != null) {
            mOnItemClicked.onItemClick(HorizontalScrollSelectView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i));
          }
          if (mOnItemSelected != null) {
            mOnItemSelected.onItemSelected(HorizontalScrollSelectView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i));
          }
          break;
        }
 
      }
      return true;
    }
 
    @Override
    public void onLongPress(MotionEvent e) {
      int childCount = getChildCount();
      for (int i = 0; i < childCount; i++) {
        View child = getChildAt(i);
        if (isEventWithinView(e, child)) {
          if (mOnItemLongClicked != null) {
            mOnItemLongClicked.onItemLongClick(HorizontalScrollSelectView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i));
          }
          break;
        }
 
      }
    }
 
    private boolean isEventWithinView(MotionEvent e, View child) {
      Rect viewRect = new Rect();
      int[] childPosition = new int[2];
      child.getLocationOnScreen(childPosition);
      int left = childPosition[0];
      int right = left + child.getWidth();
      int top = childPosition[1];
      int bottom = top + child.getHeight();
      viewRect.set(left, top, right, bottom);
      return viewRect.contains((int) e.getRawX(), (int) e.getRawY());
    }
  };