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58      * Notifies the attached observers that the underlying data is no longer valid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 Once invoked this adapter is no longer valid and should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