1/* 2 * Copyright (C) 2011 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 android.support.v4.widget; 18 19import android.database.Cursor; 20import android.widget.Filter; 21 22/** 23 * The CursorFilter delegates most of the work to the 24 * {@link android.widget.CursorAdapter}. Subclasses should override these 25 * delegate methods to run the queries and convert the results into String 26 * that can be used by auto-completion widgets. 27 */ 28class CursorFilter extends Filter { 29 30 CursorFilterClient mClient; 31 32 interface CursorFilterClient { 33 CharSequence convertToString(Cursor cursor); 34 Cursor runQueryOnBackgroundThread(CharSequence constraint); 35 Cursor getCursor(); 36 void changeCursor(Cursor cursor); 37 } 38 39 CursorFilter(CursorFilterClient client) { 40 mClient = client; 41 } 42 43 @Override 44 public CharSequence convertResultToString(Object resultValue) { 45 return mClient.convertToString((Cursor) resultValue); 46 } 47 48 @Override 49 protected FilterResults performFiltering(CharSequence constraint) { 50 Cursor cursor = mClient.runQueryOnBackgroundThread(constraint); 51 52 FilterResults results = new FilterResults(); 53 if (cursor != null) { 54 results.count = cursor.getCount(); 55 results.values = cursor; 56 } else { 57 results.count = 0; 58 results.values = null; 59 } 60 return results; 61 } 62 63 @Override 64 protected void publishResults(CharSequence constraint, FilterResults results) { 65 Cursor oldCursor = mClient.getCursor(); 66 67 if (results.values != null && results.values != oldCursor) { 68 mClient.changeCursor((Cursor) results.values); 69 } 70 } 71} 72