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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package com.android.documentsui.dirlist;
     17 
     18 import static android.support.v4.util.Preconditions.checkArgument;
     19 
     20 import android.support.annotation.Nullable;
     21 import android.support.v7.widget.RecyclerView;
     22 import android.support.v7.widget.RecyclerView.OnItemTouchListener;
     23 import android.view.MotionEvent;
     24 
     25 import com.android.documentsui.base.EventHandler;
     26 import com.android.documentsui.base.Events;
     27 import com.android.documentsui.selection.BandSelectionHelper;
     28 import com.android.documentsui.selection.ItemDetailsLookup;
     29 import com.android.documentsui.selection.TouchEventRouter;
     30 
     31 /**
     32  * OnItemTouchListener that helps enable support for drag/drop functionality
     33  * in DirectoryFragment.
     34  *
     35  * <p>This class takes an OnItemTouchListener that is presumably the
     36  * one provided by {@link BandSelectionHelper#getListener()}, and
     37  * is used in conjunction with the {@link TouchEventRouter}.
     38  *
     39  * <p>See DirectoryFragment for more details on how this is glued
     40  * into DocumetnsUI event handling to make the magic happen.
     41  */
     42 class MouseDragEventInterceptor implements OnItemTouchListener {
     43 
     44     private final ItemDetailsLookup mEventDetailsLookup;
     45     private final EventHandler<MotionEvent> mMouseDragListener;
     46     private final @Nullable OnItemTouchListener mDelegate;
     47 
     48     public MouseDragEventInterceptor(
     49             ItemDetailsLookup eventDetailsLookup,
     50             EventHandler<MotionEvent> mouseDragListener,
     51             @Nullable OnItemTouchListener delegate) {
     52 
     53         checkArgument(eventDetailsLookup != null);
     54         checkArgument(mouseDragListener != null);
     55 
     56         mEventDetailsLookup = eventDetailsLookup;
     57         mMouseDragListener = mouseDragListener;
     58         mDelegate = delegate;
     59     }
     60 
     61     @Override
     62     public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
     63         if (Events.isMouseDragEvent(e) && mEventDetailsLookup.inItemDragRegion(e)) {
     64             return mMouseDragListener.accept(e);
     65         } else if (mDelegate != null) {
     66             return mDelegate.onInterceptTouchEvent(rv, e);
     67         }
     68         return false;
     69     }
     70 
     71     @Override
     72     public void onTouchEvent(RecyclerView rv, MotionEvent e) {
     73         if (mDelegate != null) {
     74             mDelegate.onTouchEvent(rv, e);
     75         }
     76     }
     77 
     78     @Override
     79     public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {}
     80 }
     81