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 17package com.android.documentsui.dirlist; 18 19import static com.android.documentsui.base.DocumentInfo.getCursorString; 20 21import android.content.Context; 22import android.database.Cursor; 23import android.provider.DocumentsContract.Document; 24import android.support.v7.widget.GridLayoutManager; 25import android.support.v7.widget.RecyclerView; 26 27import com.android.documentsui.ActionHandler; 28import com.android.documentsui.Model; 29import com.android.documentsui.base.EventListener; 30import com.android.documentsui.base.Features; 31import com.android.documentsui.base.State; 32 33import java.util.List; 34 35/** 36 * DocumentsAdapter provides glue between a directory Model, and RecylcerView. 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 */ 44public abstract class DocumentsAdapter 45 extends RecyclerView.Adapter<DocumentHolder> { 46 // Item types used by ModelBackedDocumentsAdapter 47 public static final int ITEM_TYPE_DOCUMENT = 1; 48 public static final int ITEM_TYPE_DIRECTORY = 2; 49 // Item types used by SectionBreakDocumentsAdapterWrapper 50 public static final int ITEM_TYPE_SECTION_BREAK = Integer.MAX_VALUE; 51 public static final int ITEM_TYPE_HEADER_MESSAGE = Integer.MAX_VALUE - 1; 52 public static final int ITEM_TYPE_INFLATED_MESSAGE = Integer.MAX_VALUE - 2; 53 54 // Payloads for notifyItemChange to distinguish between selection and other events. 55 static final String SELECTION_CHANGED_MARKER = "Selection-Changed"; 56 57 /** 58 * Returns a list of model IDs of items currently in the adapter. 59 * 60 * @return A list of Model IDs. 61 */ 62 public abstract List<String> getModelIds(); 63 64 public abstract int getAdapterPosition(String modelId); 65 66 /** 67 * Triggers item-change notifications by stable ID (as opposed to position). 68 * Passing an unrecognized ID will result in a warning in logcat, but no other error. 69 */ 70 public abstract void onItemSelectionChanged(String id); 71 72 /** 73 * @return The model ID of the item at the given adapter position. 74 */ 75 public abstract String getModelId(int position); 76 77 abstract EventListener<Model.Update> getModelUpdateListener(); 78 79 /** 80 * Returns a class that yields the span size for a particular element. This is 81 * primarily useful in {@link DirectoryAddonsAdapter} where 82 * we adjust sizes. 83 */ 84 GridLayoutManager.SpanSizeLookup createSpanSizeLookup() { 85 throw new UnsupportedOperationException(); 86 } 87 88 public boolean hasModelIds() { 89 return !getModelIds().isEmpty(); 90 } 91 92 static boolean isDirectory(Cursor cursor) { 93 final String mimeType = getCursorString(cursor, Document.COLUMN_MIME_TYPE); 94 return Document.MIME_TYPE_DIR.equals(mimeType); 95 } 96 97 boolean isDirectory(Model model, int position) { 98 String modelId = getModelIds().get(position); 99 Cursor cursor = model.getItem(modelId); 100 return isDirectory(cursor); 101 } 102 103 /** 104 * Environmental access for View adapter implementations. 105 */ 106 interface Environment { 107 Context getContext(); 108 Features getFeatures(); 109 ActionHandler getActionHandler(); 110 int getColumnCount(); 111 State getDisplayState(); 112 boolean isInSearchMode(); 113 boolean isSelected(String id); 114 Model getModel(); 115 boolean isDocumentEnabled(String mimeType, int flags); 116 void initDocumentHolder(DocumentHolder holder); 117 void onBindDocumentHolder(DocumentHolder holder, Cursor cursor); 118 } 119} 120