xref: /frameworks/support/v17/leanback/src/android/support/v17/leanback/widget/FocusHighlightHelper.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package android.support.v17.leanback.widget;

import android.graphics.drawable.TransitionDrawable;
import android.support.v17.leanback.R;
import android.view.View;
import android.content.res.Resources;

import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_NONE;
import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_SMALL;
import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_MEDIUM;
import static android.support.v17.leanback.widget.FocusHighlight.ZOOM_FACTOR_LARGE;


/**
 * Setup the behavior how to highlight when a item gains focus.
 */
public class FocusHighlightHelper {

    static class BrowseItemFocusHighlight implements FocusHighlight {
        private static final int DURATION_MS = 150;

        private static float[] sScaleFactor = new float[4];

        private int mScaleIndex;

        BrowseItemFocusHighlight(int zoomIndex) {
            mScaleIndex = (zoomIndex >= 0 && zoomIndex < sScaleFactor.length) ?
                    zoomIndex : ZOOM_FACTOR_MEDIUM;
        }

        private void lazyInit(Resources resources) {
            if (sScaleFactor[ZOOM_FACTOR_NONE] == 0f) {
                sScaleFactor[ZOOM_FACTOR_NONE] = 1f;
                sScaleFactor[ZOOM_FACTOR_SMALL] =
                        resources.getFraction(R.fraction.lb_focus_zoom_factor_small, 1, 1);
                sScaleFactor[ZOOM_FACTOR_MEDIUM] =
                        resources.getFraction(R.fraction.lb_focus_zoom_factor_medium, 1, 1);
                sScaleFactor[ZOOM_FACTOR_LARGE] =
                        resources.getFraction(R.fraction.lb_focus_zoom_factor_large, 1, 1);
            }
        }

        private float getScale(View view) {
            lazyInit(view.getResources());
            return sScaleFactor[mScaleIndex];
        }

        private void viewFocused(View view, boolean hasFocus) {
            if (hasFocus) {
                final float scale = getScale(view);
                view.animate().scaleX(scale).scaleY(scale).setDuration(DURATION_MS);
            } else {
                view.animate().scaleX(1f).scaleY(1f).setDuration(DURATION_MS);
            }
            if (view instanceof ListRowCardWrapper) {
                ListRowCardWrapper wrapper = (ListRowCardWrapper) view;
                if (wrapper.mShadowNormal != null) {
                    if (hasFocus) {
                        wrapper.mShadowFocused.animate().alpha(1f)
                                .setDuration(DURATION_MS).start();
                        wrapper.mShadowNormal.animate().alpha(0f)
                                .setDuration(DURATION_MS).start();
                    } else {
                        wrapper.mShadowFocused.animate().alpha(0f)
                                .setDuration(DURATION_MS).start();
                        wrapper.mShadowNormal.animate().alpha(1f)
                                .setDuration(DURATION_MS).start();
                    }
                }
            }
        }

        @Override
        public void onItemFocused(View view, boolean hasFocus) {
            viewFocused(view, hasFocus);
        }
    }

    private static HeaderItemFocusHighlight sHeaderItemFocusHighlight =
            new HeaderItemFocusHighlight();

    private static ActionItemFocusHighlight sActionItemFocusHighlight =
            new ActionItemFocusHighlight();

    /**
     * Setup the focus highlight behavior of a focused item in browse list row.
     * @param adapter  adapter of the list row.
     */
    public static void setupBrowseItemFocusHighlight(ItemBridgeAdapter adapter, int zoomIndex) {
        adapter.setFocusHighlight(new BrowseItemFocusHighlight(zoomIndex));
    }

    /**
     * Setup the focus highlight behavior of a focused item in header list.
     * @param adapter  adapter of the header list.
     */
    public static void setupHeaderItemFocusHighlight(ItemBridgeAdapter adapter) {
        adapter.setFocusHighlight(sHeaderItemFocusHighlight);
    }

    /**
     * Setup the focus highlight behavior of a focused item in an action list.
     * @param adapter  adapter of the action list.
     */
    public static void setupActionItemFocusHighlight(ItemBridgeAdapter adapter) {
        adapter.setFocusHighlight(sActionItemFocusHighlight);
    }

    private static class HeaderItemFocusHighlight implements FocusHighlight {
        private boolean mInitialized;
        private float mSelectScale;
        private float mUnselectAlpha;
        private int mDuration;

        private void initializeDimensions(Resources res) {
            if (!mInitialized) {
                mSelectScale =
                        Float.parseFloat(res.getString(R.dimen.lb_browse_header_select_scale));
                mUnselectAlpha =
                        Float.parseFloat(res.getString(R.dimen.lb_browse_header_unselect_alpha));
                mDuration =
                        Integer.parseInt(res.getString(R.dimen.lb_browse_header_select_duration));
                mInitialized = true;
            }
        }

        private void viewFocused(View view, boolean hasFocus) {
            initializeDimensions(view.getResources());
            if (hasFocus) {
                view.animate().scaleX(mSelectScale).scaleY(mSelectScale)
                        .alpha(1f)
                        .setDuration(mDuration);
            } else {
                view.animate().scaleX(1f).scaleY(1f)
                        .alpha(mUnselectAlpha)
                        .setDuration(mDuration);
            }
        }

        @Override
        public void onItemFocused(View view, boolean hasFocus) {
            viewFocused(view, hasFocus);
        }
    }

    private static class ActionItemFocusHighlight implements FocusHighlight {
        private boolean mInitialized;
        private int mDuration;

        private void initializeDimensions(Resources res) {
            if (!mInitialized) {
                mDuration = Integer.parseInt(res.getString(R.dimen.lb_details_overview_action_select_duration));
            }
        }

        @Override
        public void onItemFocused(View view, boolean hasFocus) {
            initializeDimensions(view.getResources());
            TransitionDrawable td = (TransitionDrawable) view.getBackground();
            if (hasFocus) {
                td.startTransition(mDuration);
            } else {
                td.reverseTransition(mDuration);
            }
        }
    }
}