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
17package android.widget;
18
19import android.annotation.Nullable;
20import android.database.DataSetObservable;
21import android.database.DataSetObserver;
22import android.view.View;
23import 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 */
31public abstract class BaseAdapter implements ListAdapter, SpinnerAdapter {
32    private final DataSetObservable mDataSetObservable = new DataSetObservable();
33    private CharSequence[] mAutofillOptions;
34
35    public boolean hasStableIds() {
36        return false;
37    }
38
39    public void registerDataSetObserver(DataSetObserver observer) {
40        mDataSetObservable.registerObserver(observer);
41    }
42
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     */
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56     * Notifies the attached observers that the underlying data is no longer valid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 Once invoked this adapter is no longer valid and should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     */
60    public void notifyDataSetInvalidated() {
61        mDataSetObservable.notifyInvalidated();
62    }
63
64    public boolean areAllItemsEnabled() {
65        return true;
66    }
67
68    public boolean isEnabled(int position) {
69        return true;
70    }
71
72    public View getDropDownView(int position, View convertView, ViewGroup parent) {
73        return getView(position, convertView, parent);
74    }
75
76    public int getItemViewType(int position) {
77        return 0;
78    }
79
80    public int getViewTypeCount() {
81        return 1;
82    }
83
84    public boolean isEmpty() {
85        return getCount() == 0;
86    }
87
88    @Override
89    public CharSequence[] getAutofillOptions() {
90        return mAutofillOptions;
91    }
92
93    /**
94     * Sets the value returned by {@link #getAutofillOptions()}
95     */
96    public void setAutofillOptions(@Nullable CharSequence... options) {
97        mAutofillOptions = options;
98    }
99}
100