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.compat.annotation.UnsupportedAppUsage; 21 import android.database.DataSetObservable; 22 import android.database.DataSetObserver; 23 import android.view.View; 24 import android.view.ViewGroup; 25 26 /** 27 * Common base class of common implementation for an {@link Adapter} that can be 28 * used in both {@link ListView} (by implementing the specialized 29 * {@link ListAdapter} interface) and {@link Spinner} (by implementing the 30 * specialized {@link SpinnerAdapter} interface). 31 */ 32 public abstract class BaseAdapter implements ListAdapter, SpinnerAdapter { 33 @UnsupportedAppUsage 34 private final DataSetObservable mDataSetObservable = new DataSetObservable(); 35 private CharSequence[] mAutofillOptions; 36 hasStableIds()37 public boolean hasStableIds() { 38 return false; 39 } 40 registerDataSetObserver(DataSetObserver observer)41 public void registerDataSetObserver(DataSetObserver observer) { 42 mDataSetObservable.registerObserver(observer); 43 } 44 unregisterDataSetObserver(DataSetObserver observer)45 public void unregisterDataSetObserver(DataSetObserver observer) { 46 mDataSetObservable.unregisterObserver(observer); 47 } 48 49 /** 50 * Notifies the attached observers that the underlying data has been changed 51 * and any View reflecting the data set should refresh itself. 52 */ notifyDataSetChanged()53 public void notifyDataSetChanged() { 54 mDataSetObservable.notifyChanged(); 55 } 56 57 /** 58 * Notifies the attached observers that the underlying data is no longer valid 59 * or available. Once invoked this adapter is no longer valid and should 60 * not report further data set changes. 61 */ notifyDataSetInvalidated()62 public void notifyDataSetInvalidated() { 63 mDataSetObservable.notifyInvalidated(); 64 } 65 areAllItemsEnabled()66 public boolean areAllItemsEnabled() { 67 return true; 68 } 69 isEnabled(int position)70 public boolean isEnabled(int position) { 71 return true; 72 } 73 getDropDownView(int position, View convertView, ViewGroup parent)74 public View getDropDownView(int position, View convertView, ViewGroup parent) { 75 return getView(position, convertView, parent); 76 } 77 getItemViewType(int position)78 public int getItemViewType(int position) { 79 return 0; 80 } 81 getViewTypeCount()82 public int getViewTypeCount() { 83 return 1; 84 } 85 isEmpty()86 public boolean isEmpty() { 87 return getCount() == 0; 88 } 89 90 @Override getAutofillOptions()91 public CharSequence[] getAutofillOptions() { 92 return mAutofillOptions; 93 } 94 95 /** 96 * Sets the value returned by {@link #getAutofillOptions()} 97 */ setAutofillOptions(@ullable CharSequence... options)98 public void setAutofillOptions(@Nullable CharSequence... options) { 99 mAutofillOptions = options; 100 } 101 } 102