SuggestionsAdapter.java revision 94e8a2be78530170f50e7895a558bf8011bbf8e8 
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 = 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 ComponentName mSource = 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        mSource = 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    protected Suggestions getSuggestions() {
90        return mSuggestions;
91    }
92
93    /**
94     * Gets the source whose results are displayed.
95     */
96    public ComponentName getSource() {
97        return mSource;
98    }
99
100    /**
101     * Sets the source whose results are displayed.
102     *
103     * @param source The name of a source, or {@code null} to show
104     *        the promoted results.
105     */
106    public void setSource(ComponentName source) {
107        mSource = source;
108        onSuggestionsChanged();
109    }
110
111    public int getCount() {
112        return mCursor == null ? 0 : mCursor.getCount();
113    }
114
115    public SuggestionPosition getItem(int position) {
116        if (mCursor == null) return null;
117        return new SuggestionPosition(mCursor, position);
118    }
119
120    public long getItemId(int position) {
121        return position;
122    }
123
124    public View getView(int position, View convertView, ViewGroup parent) {
125        if (mCursor == null) {
126            throw new IllegalStateException("getView() called with null cursor");
127        }
128        SuggestionView view;
129        if (convertView == null) {
130            view = mViewFactory.createSuggestionView(parent);
131        } else {
132            view = (SuggestionView) convertView;
133        }
134        mCursor.moveTo(position);
135        view.bindAsSuggestion(mCursor);
136        return view;
137    }
138
139    protected void onSuggestionsChanged() {
140        if (DBG) Log.d(TAG, "onSuggestionsChanged(), mSuggestions=" + mSuggestions);
141        SuggestionCursor cursor = getSourceCursor(mSuggestions, mSource);
142        changeCursor(cursor);
143    }
144
145    /**
146     * Gets the cursor for the given source.
147     */
148    protected SuggestionCursor getSourceCursor(Suggestions suggestions, ComponentName source) {
149        if (suggestions == null) return null;
150        if (source == null) return suggestions.getPromoted();
151        return suggestions.getSourceResult(source);
152    }
153
154    /**
155     * Replace the cursor.
156     *
157     * This does not close the old cursor. Instead, all the cursors are closed in
158     * {@link #setSuggestions(Suggestions)}.
159     */
160    private void changeCursor(SuggestionCursor newCursor) {
161        if (DBG) Log.d(TAG, "changeCursor(" + newCursor + ")");
162        if (newCursor == mCursor) {
163            // Shortcuts may have changed without the cursor changing.
164            notifyDataSetChanged();
165            return;
166        }
167        mCursor = newCursor;
168        if (mCursor != null) {
169            // TODO: Register observers here to watch for
170            // changes in the cursor, e.g. shortcut refreshes?
171            notifyDataSetChanged();
172        } else {
173            notifyDataSetInvalidated();
174        }
175    }
176
177    private class MySuggestionsObserver extends DataSetObserver {
178        @Override
179        public void onChanged() {
180            onSuggestionsChanged();
181        }
182    }
183
184}
185