1 /* 2 * Copyright (C) 2007 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 android.widget; 18 19 import android.database.DataSetObservable; 20 import android.database.DataSetObserver; 21 import android.view.View; 22 import android.view.ViewGroup; 23 24 /** 25 * Common base class of common implementation for an {@link Adapter} that can be 26 * used in both {@link ListView} (by implementing the specialized 27 * {@link ListAdapter} interface} and {@link Spinner} (by implementing the 28 * specialized {@link SpinnerAdapter} interface. 29 */ 30 public abstract class BaseAdapter implements ListAdapter, SpinnerAdapter { 31 private final DataSetObservable mDataSetObservable = new DataSetObservable(); 32 hasStableIds()33 public boolean hasStableIds() { 34 return false; 35 } 36 registerDataSetObserver(DataSetObserver observer)37 public void registerDataSetObserver(DataSetObserver observer) { 38 mDataSetObservable.registerObserver(observer); 39 } 40 unregisterDataSetObserver(DataSetObserver observer)41 public void unregisterDataSetObserver(DataSetObserver observer) { 42 mDataSetObservable.unregisterObserver(observer); 43 } 44 45 /** 46 * Notifies the attached View that the underlying data has been changed 47 * and it should refresh itself. 48 */ notifyDataSetChanged()49 public void notifyDataSetChanged() { 50 mDataSetObservable.notifyChanged(); 51 } 52 notifyDataSetInvalidated()53 public void notifyDataSetInvalidated() { 54 mDataSetObservable.notifyInvalidated(); 55 } 56 areAllItemsEnabled()57 public boolean areAllItemsEnabled() { 58 return true; 59 } 60 isEnabled(int position)61 public boolean isEnabled(int position) { 62 return true; 63 } 64 getDropDownView(int position, View convertView, ViewGroup parent)65 public View getDropDownView(int position, View convertView, ViewGroup parent) { 66 return getView(position, convertView, parent); 67 } 68 getItemViewType(int position)69 public int getItemViewType(int position) { 70 return 0; 71 } 72 getViewTypeCount()73 public int getViewTypeCount() { 74 return 1; 75 } 76 isEmpty()77 public boolean isEmpty() { 78 return getCount() == 0; 79 } 80 } 81