SuggestionsAdapter.java revision 0484fb4d652bfa9d5c7fb238a7cec1a6f2244e44 
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.SuggestionCursor;
20import com.android.quicksearchbox.SuggestionPosition;
21import com.android.quicksearchbox.Suggestions;
22
23import android.content.ComponentName;
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 = true;
36    private static final String TAG = "QSB.SuggestionsAdapter";
37
38    private long mSourceResultPublishDelayMillis;
39    private long mInitialSourceResultWaitMillis;
40
41    private DataSetObserver mDataSetObserver;
42
43    private final SuggestionViewFactory mViewFactory;
44
45    private SuggestionCursor mCursor;
46
47    private ComponentName mSource = null;
48
49    private Suggestions mSuggestions;
50
51    private boolean mClosed = false;
52
53    public SuggestionsAdapter(SuggestionViewFactory viewFactory) {
54        mViewFactory = viewFactory;
55    }
56
57    public void setSourceResultPublishDelayMillis(long millis) {
58        mSourceResultPublishDelayMillis = millis;
59    }
60
61    public void setInitialSourceResultWaitMillis(long millis) {
62        mInitialSourceResultWaitMillis = millis;
63    }
64
65    public void close() {
66        setSuggestions(null);
67        mSource = null;
68        mClosed = true;
69    }
70
71    public void setSuggestions(Suggestions suggestions) {
72        if (mSuggestions == suggestions) {
73            return;
74        }
75        if (mClosed) {
76            if (suggestions != null) {
77                suggestions.close();
78            }
79            return;
80        }
81        if (mDataSetObserver == null) {
82            mDataSetObserver = new MySuggestionsObserver();
83        }
84        // TODO: delay the change if there are no suggestions for the currently visible tab.
85        if (mSuggestions != null) {
86            mSuggestions.unregisterDataSetObserver(mDataSetObserver);
87            mSuggestions.close();
88        }
89        mSuggestions = suggestions;
90        if (mSuggestions != null) {
91            mSuggestions.registerDataSetObserver(mDataSetObserver);
92        }
93        onSuggestionsChanged();
94    }
95
96    /**
97     * Sets the source whose results are displayed.
98     *
99     * @param source The name of a source, or {@code null} to show
100     *        the promoted results.
101     */
102    public void setSource(ComponentName source) {
103        mSource = source;
104        onSuggestionsChanged();
105    }
106
107    public int getCount() {
108        return mCursor == null ? 0 : mCursor.getCount();
109    }
110
111    public SuggestionPosition getItem(int position) {
112        if (mCursor == null) return null;
113        return new SuggestionPosition(mCursor, position);
114    }
115
116    public long getItemId(int position) {
117        return position;
118    }
119
120    public View getView(int position, View convertView, ViewGroup parent) {
121        if (mCursor == null) {
122            throw new IllegalStateException("getView() called with null cursor");
123        }
124        SuggestionView view;
125        if (convertView == null) {
126            view = mViewFactory.createSuggestionView(parent);
127        } else {
128            view = (SuggestionView) convertView;
129        }
130        mCursor.moveTo(position);
131        view.bindAsSuggestion(mCursor);
132        return view;
133    }
134
135    protected void onSuggestionsChanged() {
136        if (DBG) Log.d(TAG, "onSuggestionsChanged(), mSuggestions=" + mSuggestions);
137        SuggestionCursor cursor = getCursor();
138        changeCursor(cursor);
139    }
140
141    /**
142     * Gets the cursor for the selected source.
143     */
144    private SuggestionCursor getCursor() {
145        if (mSuggestions == null) return null;
146        if (mSource == null) return mSuggestions.getPromoted();
147        return mSuggestions.getSourceResult(mSource);
148    }
149
150    /**
151     * Replace the cursor.
152     *
153     * This does not close the old cursor. Instead, all the cursors are closed in
154     * {@link #setSuggestions(Suggestions)}.
155     */
156    private void changeCursor(SuggestionCursor newCursor) {
157        if (DBG) Log.d(TAG, "changeCursor(" + newCursor + ")");
158        if (newCursor == mCursor) {
159            return;
160        }
161        mCursor = newCursor;
162        if (mCursor != null) {
163            // TODO: Register observers here to watch for
164            // changes in the cursor, e.g. shortcut refreshes?
165            notifyDataSetChanged();
166        } else {
167            notifyDataSetInvalidated();
168        }
169    }
170
171    private class MySuggestionsObserver extends DataSetObserver {
172        @Override
173        public void onChanged() {
174            onSuggestionsChanged();
175        }
176    }
177
178}
179