SuggestionsAdapter.java revision e06b7cbf55301a24cfd7525a91107e3cd2c9f48e 
1/*
2 * Copyright (C) 2009 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.quicksearchbox.ui;
18
19import com.android.quicksearchbox.Corpus;
20import com.android.quicksearchbox.SuggestionCursor;
21import com.android.quicksearchbox.SuggestionPosition;
22import com.android.quicksearchbox.Suggestions;
23
24import android.database.DataSetObserver;
25import android.util.Log;
26import android.view.View;
27import android.view.ViewGroup;
28import android.widget.BaseAdapter;
29
30/**
31 * Uses a {@link Suggestions} object to back a {@link SuggestionsView}.
32 */
33public class SuggestionsAdapter extends BaseAdapter {
34
35    private static final boolean DBG = false;
36    private static final String TAG = "QSB.SuggestionsAdapter";
37
38    private DataSetObserver mDataSetObserver;
39
40    private final SuggestionViewFactory mViewFactory;
41
42    private SuggestionCursor mCursor;
43
44    private Corpus mCorpus = null;
45
46    private Suggestions mSuggestions;
47
48    private boolean mClosed = false;
49
50    public SuggestionsAdapter(SuggestionViewFactory viewFactory) {
51        mViewFactory = viewFactory;
52    }
53
54    public boolean isClosed() {
55        return mClosed;
56    }
57
58    public void close() {
59        setSuggestions(null);
60        mCorpus = null;
61        mClosed = true;
62    }
63
64    public void setSuggestions(Suggestions suggestions) {
65        if (mSuggestions == suggestions) {
66            return;
67        }
68        if (mClosed) {
69            if (suggestions != null) {
70                suggestions.close();
71            }
72            return;
73        }
74        if (mDataSetObserver == null) {
75            mDataSetObserver = new MySuggestionsObserver();
76        }
77        // TODO: delay the change if there are no suggestions for the currently visible tab.
78        if (mSuggestions != null) {
79            mSuggestions.unregisterDataSetObserver(mDataSetObserver);
80            mSuggestions.close();
81        }
82        mSuggestions = suggestions;
83        if (mSuggestions != null) {
84            mSuggestions.registerDataSetObserver(mDataSetObserver);
85        }
86        onSuggestionsChanged();
87    }
88
89    public Suggestions getSuggestions() {
90        return mSuggestions;
91    }
92
93    /**
94     * Gets the source whose results are displayed.
95     */
96    public Corpus getCorpus() {
97        return mCorpus;
98    }
99
100    /**
101     * Sets the source whose results are displayed.
102     */
103    public void setCorpus(Corpus corpus) {
104        mCorpus = corpus;
105        onSuggestionsChanged();
106    }
107
108    public int getCount() {
109        return mCursor == null ? 0 : mCursor.getCount();
110    }
111
112    public SuggestionPosition getItem(int position) {
113        if (mCursor == null) return null;
114        return new SuggestionPosition(mCursor, position);
115    }
116
117    public long getItemId(int position) {
118        return position;
119    }
120
121    @Override
122    public int getViewTypeCount() {
123        return mViewFactory.getSuggestionViewTypeCount();
124    }
125
126    @Override
127    public int getItemViewType(int position) {
128        if (mCursor == null) {
129            return 0;
130        }
131        mCursor.moveTo(position);
132        return mViewFactory.getSuggestionViewType(mCursor);
133    }
134
135    public View getView(int position, View convertView, ViewGroup parent) {
136        if (mCursor == null) {
137            throw new IllegalStateException("getView() called with null cursor");
138        }
139        mCursor.moveTo(position);
140        int viewType = mViewFactory.getSuggestionViewType(mCursor);
141        SuggestionView view = mViewFactory.getSuggestionView(viewType, convertView, parent);
142        view.bindAsSuggestion(mCursor);
143        return (View) view;
144    }
145
146    protected void onSuggestionsChanged() {
147        if (DBG) Log.d(TAG, "onSuggestionsChanged(), mSuggestions=" + mSuggestions);
148        SuggestionCursor cursor = getCorpusCursor(mSuggestions, mCorpus);
149        changeCursor(cursor);
150    }
151
152    /**
153     * Gets the cursor containing the currently shown suggestions. The caller should not hold
154     * on to or modify the returned cursor.
155     */
156    public SuggestionCursor getCurrentSuggestions() {
157        return mCursor;
158    }
159
160    /**
161     * Gets the cursor for the given source.
162     */
163    protected SuggestionCursor getCorpusCursor(Suggestions suggestions, Corpus corpus) {
164        if (suggestions == null) return null;
165        if (corpus == null) return suggestions.getPromoted();
166        return suggestions.getCorpusResult(corpus);
167    }
168
169    /**
170     * Replace the cursor.
171     *
172     * This does not close the old cursor. Instead, all the cursors are closed in
173     * {@link #setSuggestions(Suggestions)}.
174     */
175    private void changeCursor(SuggestionCursor newCursor) {
176        if (DBG) Log.d(TAG, "changeCursor(" + newCursor + ")");
177        if (newCursor == mCursor) {
178            // Shortcuts may have changed without the cursor changing.
179            notifyDataSetChanged();
180            return;
181        }
182        mCursor = newCursor;
183        if (mCursor != null) {
184            // TODO: Register observers here to watch for
185            // changes in the cursor, e.g. shortcut refreshes?
186            notifyDataSetChanged();
187        } else {
188            notifyDataSetInvalidated();
189        }
190    }
191
192    private class MySuggestionsObserver extends DataSetObserver {
193        @Override
194        public void onChanged() {
195            onSuggestionsChanged();
196        }
197    }
198
199}
200