FocusHighlightHelper.java revision 62d36d44e03a3dd0632b156615b04563c62e83c1 
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.graphics.drawable.TransitionDrawable;
17import android.support.v17.leanback.R;
18import android.view.View;
19import android.content.res.Resources;
20
21/**
22 * Setup the behavior how to highlight when a item gains focus.
23 */
24public class FocusHighlightHelper {
25
26    static class BrowseItemFocusHighlight implements FocusHighlight {
27        private static final int DURATION_MS = 150;
28
29        public static int ZOOM_FACTOR_NONE = 0;
30        public static int ZOOM_FACTOR_SMALL = 1;
31        public static int ZOOM_FACTOR_MEDIUM = 2;
32        public static int ZOOM_FACTOR_LARGE = 3;
33
34        private static float[] sScaleFactor = new float[4];
35
36        private int mScaleIndex;
37
38        BrowseItemFocusHighlight(int zoomIndex) {
39            mScaleIndex = (zoomIndex >= 0 && zoomIndex < sScaleFactor.length) ?
40                    zoomIndex : ZOOM_FACTOR_MEDIUM;
41        }
42
43        private void lazyInit(Resources resources) {
44            if (sScaleFactor[ZOOM_FACTOR_NONE] == 0f) {
45                sScaleFactor[ZOOM_FACTOR_NONE] = 1f;
46                sScaleFactor[ZOOM_FACTOR_SMALL] =
47                        resources.getFraction(R.fraction.lb_focus_zoom_factor_small, 1, 1);
48                sScaleFactor[ZOOM_FACTOR_MEDIUM] =
49                        resources.getFraction(R.fraction.lb_focus_zoom_factor_medium, 1, 1);
50                sScaleFactor[ZOOM_FACTOR_LARGE] =
51                        resources.getFraction(R.fraction.lb_focus_zoom_factor_large, 1, 1);
52            }
53        }
54
55        private float getScale(View view) {
56            lazyInit(view.getResources());
57            return sScaleFactor[mScaleIndex];
58        }
59
60        private void viewFocused(View view, boolean hasFocus) {
61            if (hasFocus) {
62                final float scale = getScale(view);
63                view.animate().scaleX(scale).scaleY(scale).setDuration(DURATION_MS);
64            } else {
65                view.animate().scaleX(1f).scaleY(1f).setDuration(DURATION_MS);
66            }
67        }
68
69        @Override
70        public void onItemFocused(View view, boolean hasFocus) {
71            viewFocused(view, hasFocus);
72        }
73    }
74
75    private static HeaderItemFocusHighlight sHeaderItemFocusHighlight =
76            new HeaderItemFocusHighlight();
77
78    private static ActionItemFocusHighlight sActionItemFocusHighlight =
79            new ActionItemFocusHighlight();
80
81    /**
82     * Setup the focus highlight behavior of a focused item in browse list row.
83     * @param adapter  adapter of the list row.
84     */
85    public static void setupBrowseItemFocusHighlight(ItemBridgeAdapter adapter, int zoomIndex) {
86        adapter.setFocusHighlight(new BrowseItemFocusHighlight(zoomIndex));
87    }
88
89    /**
90     * Setup the focus highlight behavior of a focused item in header list.
91     * @param adapter  adapter of the header list.
92     */
93    public static void setupHeaderItemFocusHighlight(ItemBridgeAdapter adapter) {
94        adapter.setFocusHighlight(sHeaderItemFocusHighlight);
95    }
96
97    /**
98     * Setup the focus highlight behavior of a focused item in an action list.
99     * @param adapter  adapter of the action list.
100     */
101    public static void setupActionItemFocusHighlight(ItemBridgeAdapter adapter) {
102        adapter.setFocusHighlight(sActionItemFocusHighlight);
103    }
104
105    private static class HeaderItemFocusHighlight implements FocusHighlight {
106        private boolean mInitialized;
107        private float mSelectScale;
108        private float mUnselectAlpha;
109        private int mDuration;
110
111        private void initializeDimensions(Resources res) {
112            if (!mInitialized) {
113                mSelectScale =
114                        Float.parseFloat(res.getString(R.dimen.lb_browse_header_select_scale));
115                mUnselectAlpha =
116                        Float.parseFloat(res.getString(R.dimen.lb_browse_header_unselect_alpha));
117                mDuration =
118                        Integer.parseInt(res.getString(R.dimen.lb_browse_header_select_duration));
119                mInitialized = true;
120            }
121        }
122
123        private void viewFocused(View view, boolean hasFocus) {
124            initializeDimensions(view.getResources());
125            if (hasFocus) {
126                view.animate().scaleX(mSelectScale).scaleY(mSelectScale)
127                        .alpha(1f)
128                        .setDuration(mDuration);
129            } else {
130                view.animate().scaleX(1f).scaleY(1f)
131                        .alpha(mUnselectAlpha)
132                        .setDuration(mDuration);
133            }
134        }
135
136        @Override
137        public void onItemFocused(View view, boolean hasFocus) {
138            viewFocused(view, hasFocus);
139        }
140    }
141
142    private static class ActionItemFocusHighlight implements FocusHighlight {
143        private boolean mInitialized;
144        private int mDuration;
145
146        private void initializeDimensions(Resources res) {
147            if (!mInitialized) {
148                mDuration = Integer.parseInt(res.getString(R.dimen.lb_details_overview_action_select_duration));
149            }
150        }
151
152        @Override
153        public void onItemFocused(View view, boolean hasFocus) {
154            initializeDimensions(view.getResources());
155            TransitionDrawable td = (TransitionDrawable) view.getBackground();
156            if (hasFocus) {
157                td.startTransition(mDuration);
158            } else {
159                td.reverseTransition(mDuration);
160            }
161        }
162    }
163}
164