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      1 /*
      2  * Copyright (C) 2015 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 
     17 package com.android.documentsui.dirlist;
     18 
     19 import static com.android.documentsui.base.DocumentInfo.getCursorString;
     20 
     21 import android.content.Context;
     22 import android.database.Cursor;
     23 import android.provider.DocumentsContract.Document;
     24 import android.support.v7.widget.GridLayoutManager;
     25 import android.support.v7.widget.RecyclerView;
     26 
     27 import com.android.documentsui.ActionHandler;
     28 import com.android.documentsui.Model;
     29 import com.android.documentsui.base.EventListener;
     30 import com.android.documentsui.base.Features;
     31 import com.android.documentsui.base.State;
     32 
     33 import java.util.List;
     34 
     35 /**
     36  * DocumentsAdapter provides glue between a directory Model, and RecyclerView. We've
     37  * abstracted this a bit in order to decompose some specialized support
     38  * for adding dummy layout objects (@see SectionBreakDocumentsAdapter). Handling of the
     39  * dummy layout objects was error prone when interspersed with the core mode / adapter code.
     40  *
     41  * @see ModelBackedDocumentsAdapter
     42  * @see DirectoryAddonsAdapter
     43  */
     44 public abstract class DocumentsAdapter extends RecyclerView.Adapter<DocumentHolder> {
     45     // Item types used by ModelBackedDocumentsAdapter
     46     public static final int ITEM_TYPE_DOCUMENT = 1;
     47     public static final int ITEM_TYPE_DIRECTORY = 2;
     48     // Item types used by SectionBreakDocumentsAdapterWrapper
     49     public static final int ITEM_TYPE_SECTION_BREAK = Integer.MAX_VALUE;
     50     public static final int ITEM_TYPE_HEADER_MESSAGE = Integer.MAX_VALUE - 1;
     51     public static final int ITEM_TYPE_INFLATED_MESSAGE = Integer.MAX_VALUE - 2;
     52 
     53     public abstract int getAdapterPosition(String modelId);
     54     public abstract String getStableId(int adapterPosition);
     55     public abstract List<String> getStableIds();
     56     public abstract int getPosition(String id);
     57 
     58     abstract EventListener<Model.Update> getModelUpdateListener();
     59 
     60     /**
     61      * Returns a class that yields the span size for a particular element. This is
     62      * primarily useful in {@link DirectoryAddonsAdapter} where
     63      * we adjust sizes.
     64      */
     65     GridLayoutManager.SpanSizeLookup createSpanSizeLookup() {
     66         throw new UnsupportedOperationException();
     67     }
     68 
     69     static boolean isDirectory(Cursor cursor) {
     70         final String mimeType = getCursorString(cursor, Document.COLUMN_MIME_TYPE);
     71         return Document.MIME_TYPE_DIR.equals(mimeType);
     72     }
     73 
     74     boolean isDirectory(Model model, int position) {
     75         String modelId = getStableIds().get(position);
     76         Cursor cursor = model.getItem(modelId);
     77         return isDirectory(cursor);
     78     }
     79 
     80     /**
     81      * Environmental access for View adapter implementations.
     82      */
     83     interface Environment {
     84         Context getContext();
     85         Features getFeatures();
     86         ActionHandler getActionHandler();
     87         int getColumnCount();
     88         State getDisplayState();
     89         boolean isInSearchMode();
     90         boolean isSelected(String id);
     91         Model getModel();
     92         boolean isDocumentEnabled(String mimeType, int flags);
     93         void initDocumentHolder(DocumentHolder holder);
     94         void onBindDocumentHolder(DocumentHolder holder, Cursor cursor);
     95     }
     96 }
     97