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      1 /*
      2  * Copyright (C) 2016 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.example.android.supportv7.widget;
     18 
     19 import android.graphics.Color;
     20 import android.support.v7.widget.DividerItemDecoration;
     21 import android.support.v7.widget.LinearLayoutManager;
     22 import android.support.v7.widget.RecyclerView;
     23 import android.view.LayoutInflater;
     24 import android.view.ViewGroup;
     25 import android.widget.TextView;
     26 
     27 import com.example.android.supportv7.Cheeses;
     28 import com.example.android.supportv7.R;
     29 
     30 import java.util.ArrayList;
     31 import java.util.Arrays;
     32 
     33 /**
     34  * A sample nested RecyclerView activity.
     35  */
     36 public class NestedRecyclerViewActivity extends BaseLayoutManagerActivity<LinearLayoutManager> {
     37     @Override
     38     protected LinearLayoutManager createLayoutManager() {
     39         return new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
     40     }
     41 
     42     @Override
     43     protected void onRecyclerViewInit(RecyclerView recyclerView) {
     44         recyclerView.addItemDecoration(
     45                 new DividerItemDecoration(this, mLayoutManager.getOrientation()));
     46     }
     47 
     48     static class InnerAdapter extends RecyclerView.Adapter<InnerAdapter.ViewHolder> {
     49         public static class ViewHolder extends RecyclerView.ViewHolder {
     50             public TextView mTextView;
     51 
     52             public ViewHolder(TextView itemView) {
     53                 super(itemView);
     54                 mTextView = itemView;
     55             }
     56         }
     57 
     58         private String[] mData;
     59 
     60         public InnerAdapter(String[] data) {
     61             mData = data;
     62         }
     63 
     64         @Override
     65         public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
     66             LayoutInflater inflater = LayoutInflater.from(parent.getContext());
     67             TextView textView = (TextView) inflater.inflate(R.layout.nested_item, parent, false);
     68             textView.setMinimumWidth(300);
     69             textView.setMinimumHeight(300);
     70             return new ViewHolder(textView);
     71         }
     72 
     73         @Override
     74         public void onBindViewHolder(ViewHolder holder, int position) {
     75             holder.mTextView.setText(mData[position]);
     76             boolean even = position % 2 == 0;
     77             holder.mTextView.setBackgroundColor(even ? Color.TRANSPARENT : 0x2fffffff);
     78         }
     79 
     80         @Override
     81         public int getItemCount() {
     82             return mData.length;
     83         }
     84     }
     85 
     86     static class OuterAdapter extends RecyclerView.Adapter<OuterAdapter.ViewHolder> {
     87         public static class ViewHolder extends RecyclerView.ViewHolder {
     88             private final RecyclerView mRecyclerView;
     89             public ViewHolder(RecyclerView itemView) {
     90                 super(itemView);
     91                 mRecyclerView = itemView;
     92             }
     93         }
     94 
     95         ArrayList<InnerAdapter> mAdapters = new ArrayList<>();
     96         RecyclerView.RecycledViewPool mSharedPool = new RecyclerView.RecycledViewPool();
     97 
     98         public OuterAdapter(String[] data) {
     99             int currentCharIndex = 0;
    100             char currentChar = data[0].charAt(0);
    101             for (int i = 1; i <= data.length; i++) {
    102                 if (i == data.length || data[i].charAt(0) != currentChar) {
    103                     mAdapters.add(new InnerAdapter(
    104                             Arrays.copyOfRange(data, currentCharIndex, i - 1)));
    105                     if (i < data.length) {
    106                         currentChar = data[i].charAt(0);
    107                         currentCharIndex = i;
    108                     }
    109                 }
    110             }
    111         }
    112 
    113         @Override
    114         public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    115             RecyclerView rv = new RecyclerView(parent.getContext());
    116             rv.setLayoutManager(new LinearLayoutManager(parent.getContext(),
    117                     LinearLayoutManager.HORIZONTAL, false));
    118             rv.setRecycledViewPool(mSharedPool);
    119             return new ViewHolder(rv);
    120         }
    121 
    122         @Override
    123         public void onBindViewHolder(ViewHolder holder, int position) {
    124             holder.mRecyclerView.setAdapter(mAdapters.get(position));
    125         }
    126 
    127         @Override
    128         public int getItemCount() {
    129             return mAdapters.size();
    130         }
    131     }
    132 
    133     protected RecyclerView.Adapter createAdapter() {
    134         return new OuterAdapter(Cheeses.sCheeseStrings);
    135     }
    136 }
    137