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.annotation.Nullable; 20 import android.database.DataSetObservable; 21 import android.database.DataSetObserver; 22 import android.view.View; 23 import android.view.ViewGroup; 24 25 /** 26 * Common base class of common implementation for an {@link Adapter} that can be 27 * used in both {@link ListView} (by implementing the specialized 28 * {@link ListAdapter} interface) and {@link Spinner} (by implementing the 29 * specialized {@link SpinnerAdapter} interface). 30 */ 31 public abstract class BaseAdapter implements ListAdapter, SpinnerAdapter { 32 private final DataSetObservable mDataSetObservable = new DataSetObservable(); 33 private CharSequence[] mAutofillOptions; 34 hasStableIds()35 public boolean hasStableIds() { 36 return false; 37 } 38 registerDataSetObserver(DataSetObserver observer)39 public void registerDataSetObserver(DataSetObserver observer) { 40 mDataSetObservable.registerObserver(observer); 41 } 42 unregisterDataSetObserver(DataSetObserver observer)43 public void unregisterDataSetObserver(DataSetObserver observer) { 44 mDataSetObservable.unregisterObserver(observer); 45 } 46 47 /** 48 * Notifies the attached observers that the underlying data has been changed 49 * and any View reflecting the data set should refresh itself. 50 */ notifyDataSetChanged()51 public void notifyDataSetChanged() { 52 mDataSetObservable.notifyChanged(); 53 } 54 55 /** 56 * Notifies the attached observers that the underlying data is no longer valid 57 * or available. Once invoked this adapter is no longer valid and should 58 * not report further data set changes. 59 */ notifyDataSetInvalidated()60 public void notifyDataSetInvalidated() { 61 mDataSetObservable.notifyInvalidated(); 62 } 63 areAllItemsEnabled()64 public boolean areAllItemsEnabled() { 65 return true; 66 } 67 isEnabled(int position)68 public boolean isEnabled(int position) { 69 return true; 70 } 71 getDropDownView(int position, View convertView, ViewGroup parent)72 public View getDropDownView(int position, View convertView, ViewGroup parent) { 73 return getView(position, convertView, parent); 74 } 75 getItemViewType(int position)76 public int getItemViewType(int position) { 77 return 0; 78 } 79 getViewTypeCount()80 public int getViewTypeCount() { 81 return 1; 82 } 83 isEmpty()84 public boolean isEmpty() { 85 return getCount() == 0; 86 } 87 88 @Override getAutofillOptions()89 public CharSequence[] getAutofillOptions() { 90 return mAutofillOptions; 91 } 92 93 /** 94 * Sets the value returned by {@link #getAutofillOptions()} 95 */ setAutofillOptions(@ullable CharSequence... options)96 public void setAutofillOptions(@Nullable CharSequence... options) { 97 mAutofillOptions = options; 98 } 99 } 100