content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * 
   *   http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.weex.ui.view.listview;
  
  import android.content.Context;
  import android.graphics.PointF;
  import android.support.v7.widget.LinearLayoutManager;
  import android.support.v7.widget.LinearSmoothScroller;
  import android.support.v7.widget.RecyclerView;
  
  /**
   * Created by moxun on 17/2/16.
   */
  
  public class ExtendedLinearLayoutManager extends LinearLayoutManager{
  
      private RecyclerView.SmoothScroller smoothScroller;
  
  
      private OnSmoothScrollEndListener onScrollEndListener;
  
      public ExtendedLinearLayoutManager(Context context) {
          super(context, VERTICAL, false);
      }
  
      public ExtendedLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
          super(context, orientation, reverseLayout);
      }
  
      @Override
      public boolean supportsPredictiveItemAnimations() {
          return false;
      }
  
      public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
          try {
              super.onLayoutChildren(recycler, state);
          } catch (IndexOutOfBoundsException e) {
              e.printStackTrace();
  
          }
      }
  
      @Override
      public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
          try {
              return super.scrollVerticallyBy(dy, recycler, state);
          } catch (Exception e) {
              e.printStackTrace();
          }
          return 0;
      }
  
  
      @Override
      public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state,
                                         int position) {
          if (smoothScroller == null) {
              smoothScroller = new ExtendedLinearLayoutManager.TopSnappedSmoothScroller(recyclerView.getContext());
          }
          smoothScroller.setTargetPosition(position);
          startSmoothScroll(smoothScroller);
      }
  
      private class TopSnappedSmoothScroller extends LinearSmoothScroller {
          public TopSnappedSmoothScroller(Context context) {
              super(context);
  
          }
  
          @Override
          public PointF computeScrollVectorForPosition(int targetPosition) {
              return ExtendedLinearLayoutManager.this
                      .computeScrollVectorForPosition(targetPosition);
          }
  
          @Override
          protected int getVerticalSnapPreference() {
              return SNAP_TO_START;
          }
  
          @Override
          protected void onStop() {
              super.onStop();
              if(onScrollEndListener != null){
                  onScrollEndListener.onStop();
                  onScrollEndListener = null;
              }
          }
      }
  
      public void setOnScrollEndListener(OnSmoothScrollEndListener onScrollEndListener) {
          this.onScrollEndListener = onScrollEndListener;
      }
  
      public interface OnSmoothScrollEndListener {
          void  onStop();
      }
  }
  