ItemAdapter.java revision 960c0ea0b1d36904beef0f01715dd43a211e88ca 
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.setupwizardlib.items;
18
19import android.util.SparseIntArray;
20import android.view.LayoutInflater;
21import android.view.View;
22import android.view.ViewGroup;
23import android.widget.BaseAdapter;
24
25/**
26 * An adapter typically used with ListView to display an
27 * {@link com.android.setupwizardlib.items.ItemHierarchy}. The item hierarchy used to create this
28 * adapter can be inflated by {@link ItemInflater} from XML.
29 */
30public class ItemAdapter extends BaseAdapter implements ItemHierarchy.Observer {
31
32    private final ItemHierarchy mItemHierarchy;
33    private ViewTypes mViewTypes = new ViewTypes();
34
35    public ItemAdapter(ItemHierarchy hierarchy) {
36        mItemHierarchy = hierarchy;
37        mItemHierarchy.registerObserver(this);
38        refreshViewTypes();
39    }
40
41    @Override
42    public int getCount() {
43        return mItemHierarchy.getCount();
44    }
45
46    @Override
47    public IItem getItem(int position) {
48        return mItemHierarchy.getItemAt(position);
49    }
50
51    @Override
52    public long getItemId(int position) {
53        return position;
54    }
55
56    @Override
57    public int getItemViewType(int position) {
58        IItem item = getItem(position);
59        int layoutRes = item.getLayoutResource();
60        return mViewTypes.get(layoutRes);
61    }
62
63    @Override
64    public int getViewTypeCount() {
65        return mViewTypes.size();
66    }
67
68    private void refreshViewTypes() {
69        for (int i = 0; i < getCount(); i++) {
70            IItem item = getItem(i);
71            mViewTypes.add(item.getLayoutResource());
72        }
73    }
74
75    @Override
76    public View getView(int position, View convertView, ViewGroup parent) {
77        IItem item = getItem(position);
78        if (convertView == null) {
79            LayoutInflater inflater = LayoutInflater.from(parent.getContext());
80            convertView = inflater.inflate(item.getLayoutResource(), parent, false);
81        }
82        item.onBindView(convertView);
83        return convertView;
84    }
85
86    @Override
87    public void onChanged(ItemHierarchy hierarchy) {
88        refreshViewTypes();
89        notifyDataSetChanged();
90    }
91
92    @Override
93    public boolean isEnabled(int position) {
94        return getItem(position).isEnabled();
95    }
96
97    public ItemHierarchy findItemById(int id) {
98        return mItemHierarchy.findItemById(id);
99    }
100
101    public ItemHierarchy getRootItemHierarchy() {
102        return mItemHierarchy;
103    }
104
105    /**
106     * A helper class to pack a sparse set of integers (e.g. resource IDs) to a contiguous list of
107     * integers (e.g. adapter positions), providing mapping to retrieve the original ID from a given
108     * position. This is used to pack the view types of the adapter into contiguous integers from
109     * a given layout resource.
110     */
111    private static class ViewTypes {
112        private SparseIntArray mPositionMap = new SparseIntArray();
113        private int nextPosition = 0;
114
115        public int add(int id) {
116            if (mPositionMap.indexOfKey(id) < 0) {
117                mPositionMap.put(id, nextPosition);
118                nextPosition++;
119            }
120            return mPositionMap.get(id);
121        }
122
123        public int size() {
124            return mPositionMap.size();
125        }
126
127        public int get(int id) {
128            return mPositionMap.get(id);
129        }
130    }
131}
132