1/*
2 * Copyright (C) 2011 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.v4.view;
18
19import android.view.ViewConfiguration;
20
21/**
22 * Helper for accessing features in {@link ViewConfiguration}
23 * introduced after API level 4 in a backwards compatible fashion.
24 */
25public class ViewConfigurationCompat {
26    /**
27     * Interface for the full API.
28     */
29    interface ViewConfigurationVersionImpl {
30        public int getScaledPagingTouchSlop(ViewConfiguration config);
31    }
32
33    /**
34     * Interface implementation that doesn't use anything about v4 APIs.
35     */
36    static class BaseViewConfigurationVersionImpl implements ViewConfigurationVersionImpl {
37        @Override
38        public int getScaledPagingTouchSlop(ViewConfiguration config) {
39            return config.getScaledTouchSlop();
40        }
41    }
42
43    /**
44     * Interface implementation for devices with at least v11 APIs.
45     */
46    static class FroyoViewConfigurationVersionImpl implements ViewConfigurationVersionImpl {
47        @Override
48        public int getScaledPagingTouchSlop(ViewConfiguration config) {
49            return ViewConfigurationCompatFroyo.getScaledPagingTouchSlop(config);
50        }
51    }
52
53    /**
54     * Select the correct implementation to use for the current platform.
55     */
56    static final ViewConfigurationVersionImpl IMPL;
57    static {
58        if (android.os.Build.VERSION.SDK_INT >= 11) {
59            IMPL = new FroyoViewConfigurationVersionImpl();
60        } else {
61            IMPL = new BaseViewConfigurationVersionImpl();
62        }
63    }
64
65    // -------------------------------------------------------------------
66
67    /**
68     * Call {@link ViewConfiguration#getScaledPagingTouchSlop()}.
69     * If running on a pre-{@link android.os.Build.VERSION_CODES#FROYO} device,
70     * returns {@link ViewConfiguration#getScaledTouchSlop()}.
71     */
72    public static int getScaledPagingTouchSlop(ViewConfiguration config) {
73        return IMPL.getScaledPagingTouchSlop(config);
74    }
75}
76