FocusHighlightHelper.java revision 7c004076d5289caa0af7b5fb04cf7a3374be56b1 
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.view.ViewGroup;
20import android.view.animation.AccelerateDecelerateInterpolator;
21import android.view.animation.Interpolator;
22import android.animation.TimeAnimator;
23import android.content.res.Resources;
24
25import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_NONE;
26import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_SMALL;
27import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_MEDIUM;
28import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_LARGE;
29
30
31/**
32 * Setup the behavior how to highlight when a item gains focus.
33 */
34public class FocusHighlightHelper {
35
36    static class FocusAnimator implements TimeAnimator.TimeListener {
37        private final View mView;
38        private final int mDuration;
39        private final ShadowOverlayContainer mWrapper;
40        private final float mScaleDiff;
41        private float mFocusLevel = 0f;
42        private float mFocusLevelStart;
43        private float mFocusLevelDelta;
44        private final TimeAnimator mAnimator = new TimeAnimator();
45        private final Interpolator mInterpolator = new AccelerateDecelerateInterpolator();
46
47        void animateFocus(boolean select, boolean immediate) {
48            endAnimation();
49            final float end = select ? 1 : 0;
50            if (immediate) {
51                setFocusLevel(end);
52            } else if (mFocusLevel != end) {
53                mFocusLevelStart = mFocusLevel;
54                mFocusLevelDelta = end - mFocusLevelStart;
55                mAnimator.start();
56            }
57        }
58
59        FocusAnimator(View view, float scale, int duration) {
60            mView = view;
61            mDuration = duration;
62            mScaleDiff = scale - 1f;
63            if (view instanceof ShadowOverlayContainer) {
64                mWrapper = (ShadowOverlayContainer) view;
65            } else {
66                mWrapper = null;
67            }
68            mAnimator.setTimeListener(this);
69        }
70
71        void setFocusLevel(float level) {
72            mFocusLevel = level;
73            float scale = 1f + mScaleDiff * level;
74            mView.setScaleX(scale);
75            mView.setScaleY(scale);
76            if (mWrapper != null) {
77                mWrapper.setShadowFocusLevel(level);
78            }
79        }
80
81        float getFocusLevel() {
82            return mFocusLevel;
83        }
84
85        void endAnimation() {
86            mAnimator.end();
87        }
88
89        @Override
90        public void onTimeUpdate(TimeAnimator animation, long totalTime, long deltaTime) {
91            float fraction;
92            if (totalTime >= mDuration) {
93                fraction = 1;
94                mAnimator.end();
95            } else {
96                fraction = (float) (totalTime / (double) mDuration);
97            }
98            if (mInterpolator != null) {
99                fraction = mInterpolator.getInterpolation(fraction);
100            }
101            setFocusLevel(mFocusLevelStart + fraction * mFocusLevelDelta);
102        }
103    }
104
105    static class BrowseItemFocusHighlight implements FocusHighlight {
106        private static final int DURATION_MS = 150;
107
108        private static float[] sScaleFactor = new float[4];
109
110        private int mScaleIndex;
111
112        BrowseItemFocusHighlight(int zoomIndex) {
113            mScaleIndex = (zoomIndex >= 0 && zoomIndex < sScaleFactor.length) ?
114                    zoomIndex : ZOOM_FACTOR_MEDIUM;
115        }
116
117        private static void lazyInit(Resources resources) {
118            if (sScaleFactor[ZOOM_FACTOR_NONE] == 0f) {
119                sScaleFactor[ZOOM_FACTOR_NONE] = 1f;
120                sScaleFactor[ZOOM_FACTOR_SMALL] =
121                        resources.getFraction(R.fraction.lb_focus_zoom_factor_small, 1, 1);
122                sScaleFactor[ZOOM_FACTOR_MEDIUM] =
123                        resources.getFraction(R.fraction.lb_focus_zoom_factor_medium, 1, 1);
124                sScaleFactor[ZOOM_FACTOR_LARGE] =
125                        resources.getFraction(R.fraction.lb_focus_zoom_factor_large, 1, 1);
126            }
127        }
128
129        private float getScale(View view) {
130            lazyInit(view.getResources());
131            return sScaleFactor[mScaleIndex];
132        }
133
134        private void viewFocused(View view, boolean hasFocus) {
135            view.setSelected(hasFocus);
136            FocusAnimator animator = (FocusAnimator) view.getTag(R.id.lb_focus_animator);
137            if (animator == null) {
138                animator = new FocusAnimator(view, getScale(view), DURATION_MS);
139                view.setTag(R.id.lb_focus_animator, animator);
140            }
141            animator.animateFocus(hasFocus, false);
142        }
143
144        @Override
145        public void onItemFocused(View view, boolean hasFocus) {
146            viewFocused(view, hasFocus);
147        }
148    }
149
150    /**
151     * Setup the focus highlight behavior of a focused item in browse list row.
152     * @param adapter  adapter of the list row.
153     */
154    public static void setupBrowseItemFocusHighlight(ItemBridgeAdapter adapter, int zoomIndex) {
155        adapter.setFocusHighlight(new BrowseItemFocusHighlight(zoomIndex));
156    }
157
158    /**
159     * Setup the focus highlight behavior of a focused item in header list.
160     * @param gridView  the header list.
161     */
162    public static void setupHeaderItemFocusHighlight(VerticalGridView gridView) {
163        if (gridView.getAdapter() instanceof ItemBridgeAdapter) {
164            ((ItemBridgeAdapter) gridView.getAdapter())
165                    .setFocusHighlight(new HeaderItemFocusHighlight(gridView));
166        }
167    }
168
169    static class HeaderItemFocusHighlight implements FocusHighlight {
170        private static boolean sInitialized;
171        private static float sSelectScale;
172        private static int sDuration;
173        private BaseGridView mGridView;
174
175        HeaderItemFocusHighlight(BaseGridView gridView) {
176            mGridView = gridView;
177            lazyInit(gridView.getContext().getResources());
178        }
179
180        private static void lazyInit(Resources res) {
181            if (!sInitialized) {
182                sSelectScale =
183                        Float.parseFloat(res.getString(R.dimen.lb_browse_header_select_scale));
184                sDuration =
185                        Integer.parseInt(res.getString(R.dimen.lb_browse_header_select_duration));
186                sInitialized = true;
187            }
188        }
189
190        class HeaderFocusAnimator extends FocusAnimator {
191
192            ItemBridgeAdapter.ViewHolder mViewHolder;
193            HeaderFocusAnimator(View view, float scale, int duration) {
194                super(view, scale, duration);
195                mViewHolder = (ItemBridgeAdapter.ViewHolder) mGridView.getChildViewHolder(view);
196            }
197
198            @Override
199            void setFocusLevel(float level) {
200                Presenter presenter = mViewHolder.getPresenter();
201                if (presenter instanceof RowHeaderPresenter) {
202                    ((RowHeaderPresenter) presenter).setSelectLevel(
203                            ((RowHeaderPresenter.ViewHolder) mViewHolder.getViewHolder()), level);
204                }
205                super.setFocusLevel(level);
206            }
207
208        }
209
210        private void viewFocused(View view, boolean hasFocus) {
211            view.setSelected(hasFocus);
212            FocusAnimator animator = (FocusAnimator) view.getTag(R.id.lb_focus_animator);
213            if (animator == null) {
214                animator = new HeaderFocusAnimator(view, sSelectScale, sDuration);
215                view.setTag(R.id.lb_focus_animator, animator);
216            }
217            animator.animateFocus(hasFocus, false);
218        }
219
220        @Override
221        public void onItemFocused(View view, boolean hasFocus) {
222            viewFocused(view, hasFocus);
223        }
224    }
225}
226