1/*
2 * Copyright (C) 2013 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 */
16package android.view;
17
18import android.content.Context;
19import android.graphics.drawable.Drawable;
20
21/**
22 * A group overlay is an extra layer that sits on top of a ViewGroup
23 * (the "host view") which is drawn after all other content in that view
24 * (including the view group's children). Interaction with the overlay
25 * layer is done by adding and removing views and drawables.
26 *
27 * <p>ViewGroupOverlay is a subclass of {@link ViewOverlay}, adding the ability to
28 * manage views for overlays on ViewGroups, in addition to the drawable
29 * support in ViewOverlay.</p>
30 *
31 * @see ViewGroup#getOverlay()
32 */
33public class ViewGroupOverlay extends ViewOverlay {
34
35    ViewGroupOverlay(Context context, View hostView) {
36        super(context, hostView);
37    }
38
39    /**
40     * Adds a View to the overlay. The bounds of the added view should be
41     * relative to the host view. Any view added to the overlay should be
42     * removed when it is no longer needed or no longer visible.
43     *
44     * <p>Views in the overlay are visual-only; they do not receive input
45     * events and do not participate in focus traversal. Overlay views
46     * are intended to be transient, such as might be needed by a temporary
47     * animation effect.</p>
48     *
49     * <p>If the view has a parent, the view will be removed from that parent
50     * before being added to the overlay. Also, if that parent is attached
51     * in the current view hierarchy, the view will be repositioned
52     * such that it is in the same relative location inside the activity. For
53     * example, if the view's current parent lies 100 pixels to the right
54     * and 200 pixels down from the origin of the overlay's
55     * host view, then the view will be offset by (100, 200).</p>
56     *
57     * @param view The View to be added to the overlay. The added view will be
58     * drawn when the overlay is drawn.
59     * @see #remove(View)
60     * @see ViewOverlay#add(Drawable)
61     */
62    public void add(View view) {
63        mOverlayViewGroup.add(view);
64    }
65
66    /**
67     * Removes the specified View from the overlay.
68     *
69     * @param view The View to be removed from the overlay.
70     * @see #add(View)
71     * @see ViewOverlay#remove(Drawable)
72     */
73    public void remove(View view) {
74        mOverlayViewGroup.remove(view);
75    }
76}
77