ShadowHelper.java revision 254b417129de2a8c5612826a152f8a26c8f1d0e8 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14package android.support.v17.leanback.widget;
15
16import android.os.Build;
17import android.view.ViewGroup;
18import android.view.View;
19
20
21/**
22 * Helper for shadow.
23 */
24final class ShadowHelper {
25
26    final static ShadowHelper sInstance = new ShadowHelper();
27    boolean mSupportsDynamicShadow;
28    ShadowHelperVersionImpl mImpl;
29
30    /**
31     * Interface implemented by classes that support Shadow.
32     */
33    static interface ShadowHelperVersionImpl {
34        public Object addDynamicShadow(
35                View shadowContainer, float unfocusedZ, float focusedZ, boolean roundedCorners);
36        public void setZ(View view, float z);
37        public void setShadowFocusLevel(Object impl, float level);
38    }
39
40    /**
41     * Interface used when we do not support Shadow animations.
42     */
43    private static final class ShadowHelperStubImpl implements ShadowHelperVersionImpl {
44        @Override
45        public Object addDynamicShadow(
46                View shadowContainer, float focusedZ, float unfocusedZ, boolean roundedCorners) {
47            // do nothing
48            return null;
49        }
50
51        @Override
52        public void setShadowFocusLevel(Object impl, float level) {
53            // do nothing
54        }
55
56        @Override
57        public void setZ(View view, float z) {
58            // do nothing
59        }
60    }
61
62    /**
63     * Implementation used on api 21 (and above).
64     */
65    private static final class ShadowHelperApi21Impl implements ShadowHelperVersionImpl {
66        @Override
67        public Object addDynamicShadow(
68                View shadowContainer, float unfocusedZ, float focusedZ, boolean roundedCorners) {
69            return ShadowHelperApi21.addDynamicShadow(
70                    shadowContainer, unfocusedZ, focusedZ, roundedCorners);
71        }
72
73        @Override
74        public void setShadowFocusLevel(Object impl, float level) {
75            ShadowHelperApi21.setShadowFocusLevel(impl, level);
76        }
77
78        @Override
79        public void setZ(View view, float z) {
80            ShadowHelperApi21.setZ(view, z);
81        }
82    }
83
84    /**
85     * Returns the ShadowHelper.
86     */
87    private ShadowHelper() {
88        if (Build.VERSION.SDK_INT >= 21) {
89            mSupportsDynamicShadow = true;
90            mImpl = new ShadowHelperApi21Impl();
91        } else {
92            mImpl = new ShadowHelperStubImpl();
93        }
94    }
95
96    public static ShadowHelper getInstance() {
97        return sInstance;
98    }
99
100    public boolean supportsDynamicShadow() {
101        return mSupportsDynamicShadow;
102    }
103
104    public Object addDynamicShadow(
105            View shadowContainer, float unfocusedZ, float focusedZ, boolean roundedCorners) {
106        return mImpl.addDynamicShadow(shadowContainer, unfocusedZ, focusedZ, roundedCorners);
107    }
108
109    public void setShadowFocusLevel(Object impl, float level) {
110        mImpl.setShadowFocusLevel(impl, level);
111    }
112
113    /**
114     * Set the view z coordinate.
115     */
116    public void setZ(View view, float z) {
117        mImpl.setZ(view, z);
118    }
119
120}
121