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 17 package com.android.quicksearchbox.ui; 18 19 import com.android.quicksearchbox.SuggestionCursor; 20 import com.android.quicksearchbox.Suggestions; 21 22 import android.database.DataSetObserver; 23 import android.util.Log; 24 25 /** 26 * A {@link SuggestionsAdapter} that doesn't expose the new suggestions 27 * until there are some results to show. 28 */ 29 public class DelayingSuggestionsAdapter extends SuggestionsAdapter { 30 31 private static final boolean DBG = false; 32 private static final String TAG = "QSB.DelayingSuggestionsAdapter"; 33 34 private DataSetObserver mPendingDataSetObserver; 35 36 private Suggestions mPendingSuggestions; 37 DelayingSuggestionsAdapter(SuggestionViewFactory viewFactory)38 public DelayingSuggestionsAdapter(SuggestionViewFactory viewFactory) { 39 super(viewFactory); 40 } 41 42 @Override close()43 public void close() { 44 setPendingSuggestions(null); 45 super.close(); 46 } 47 48 @Override setSuggestions(Suggestions suggestions)49 public void setSuggestions(Suggestions suggestions) { 50 if (suggestions == null) { 51 super.setSuggestions(null); 52 setPendingSuggestions(null); 53 return; 54 } 55 if (shouldPublish(suggestions)) { 56 if (DBG) Log.d(TAG, "Publishing suggestions immediately: " + suggestions); 57 super.setSuggestions(suggestions); 58 // Clear any old pending suggestions. 59 setPendingSuggestions(null); 60 } else { 61 if (DBG) Log.d(TAG, "Delaying suggestions publishing: " + suggestions); 62 setPendingSuggestions(suggestions); 63 } 64 } 65 66 /** 67 * Gets whether the given suggestions are non-empty for the selected source. 68 */ shouldPublish(Suggestions suggestions)69 private boolean shouldPublish(Suggestions suggestions) { 70 if (suggestions.isDone()) return true; 71 SuggestionCursor cursor = getCorpusCursor(suggestions, getCorpus()); 72 return cursor != null && cursor.getCount() > 0; 73 } 74 setPendingSuggestions(Suggestions suggestions)75 private void setPendingSuggestions(Suggestions suggestions) { 76 if (mPendingSuggestions == suggestions) { 77 return; 78 } 79 if (isClosed()) { 80 if (suggestions != null) { 81 suggestions.close(); 82 } 83 return; 84 } 85 if (mPendingDataSetObserver == null) { 86 mPendingDataSetObserver = new PendingSuggestionsObserver(); 87 } 88 if (mPendingSuggestions != null) { 89 mPendingSuggestions.unregisterDataSetObserver(mPendingDataSetObserver); 90 // Close old suggestions, but only if they are not also the current 91 // suggestions. 92 if (mPendingSuggestions != getSuggestions()) { 93 mPendingSuggestions.close(); 94 } 95 } 96 mPendingSuggestions = suggestions; 97 if (mPendingSuggestions != null) { 98 mPendingSuggestions.registerDataSetObserver(mPendingDataSetObserver); 99 } 100 } 101 onPendingSuggestionsChanged()102 protected void onPendingSuggestionsChanged() { 103 if (DBG) { 104 Log.d(TAG, "onPendingSuggestionsChanged(), mPendingSuggestions=" 105 + mPendingSuggestions); 106 } 107 if (shouldPublish(mPendingSuggestions)) { 108 if (DBG) Log.d(TAG, "Suggestions now available, publishing: " + mPendingSuggestions); 109 super.setSuggestions(mPendingSuggestions); 110 // The suggestions are no longer pending. 111 setPendingSuggestions(null); 112 } 113 } 114 115 private class PendingSuggestionsObserver extends DataSetObserver { 116 @Override onChanged()117 public void onChanged() { 118 onPendingSuggestionsChanged(); 119 } 120 } 121 122 } 123