1/*
2 * Copyright (C) 2017 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.support.wear.internal.widget.drawer;
18
19import android.support.annotation.MainThread;
20import android.support.annotation.RestrictTo;
21import android.support.annotation.RestrictTo.Scope;
22import android.support.wear.widget.drawer.WearableNavigationDrawerView.OnItemSelectedListener;
23import android.support.wear.widget.drawer.WearableNavigationDrawerView.WearableNavigationDrawerAdapter;
24
25import java.util.HashSet;
26import java.util.Set;
27
28/**
29 * Controls the behavior of this view where the behavior may differ between single and multi-page.
30 *
31 * @hide
32 */
33@RestrictTo(Scope.LIBRARY_GROUP)
34public abstract class WearableNavigationDrawerPresenter {
35
36    private final Set<OnItemSelectedListener> mOnItemSelectedListeners = new HashSet<>();
37
38    /**
39     * Indicates to the presenter that the underlying data has changed.
40     */
41    @MainThread
42    public abstract void onDataSetChanged();
43
44    /**
45     * Indicates to the presenter that the drawer has a new adapter.
46     */
47    @MainThread
48    public abstract void onNewAdapter(WearableNavigationDrawerAdapter adapter);
49
50    /**
51     * Indicates to the presenter that the user has selected an item.
52     */
53    @MainThread
54    public abstract void onSelected(int index);
55
56    /**
57     * Indicates to the presenter that the developer wishes to change which item is selected.
58     */
59    @MainThread
60    public abstract void onSetCurrentItemRequested(int index, boolean smoothScrollTo);
61
62    /**
63     * Indicates to the presenter that the user has tapped on the drawer.
64     *
65     * @return {@code true} if the touch event has been handled and should not propagate further.
66     */
67    @MainThread
68    public abstract boolean onDrawerTapped();
69
70    /**
71     * Indicates to the presenter that a new {@link OnItemSelectedListener} has been added.
72     */
73    @MainThread
74    public void onItemSelectedListenerAdded(OnItemSelectedListener listener) {
75        mOnItemSelectedListeners.add(listener);
76    }
77
78    /**
79     * Indicates to the presenter that an {@link OnItemSelectedListener} has been removed.
80     */
81    @MainThread
82    public void onItemSelectedListenerRemoved(OnItemSelectedListener listener) {
83        mOnItemSelectedListeners.remove(listener);
84    }
85
86    /**
87     * Notifies all listeners that the item at {@code selectedPos} has been selected.
88     */
89    @MainThread
90    void notifyItemSelectedListeners(int selectedPos) {
91        for (OnItemSelectedListener listener : mOnItemSelectedListeners) {
92            listener.onItemSelected(selectedPos);
93        }
94    }
95}
96