1/* 2 * Copyright (c) 2016, 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 com.android.car.radio; 18 19import android.animation.ValueAnimator; 20import android.content.Context; 21import android.support.v7.widget.RecyclerView; 22import android.view.View; 23import com.android.car.view.PagedListView; 24 25/** 26 * Listener on the preset list that will add elevation on the container holding the current 27 * playing radio station. This elevation will give the illusion of the preset list scrolling 28 * under that container. 29 */ 30public class PresetListScrollListener extends RecyclerView.OnScrollListener { 31 private static final int ANIMATION_DURATION_MS = 100; 32 33 private final float mContainerElevation; 34 private final View mCurrentRadioCardContainer; 35 private final View mCurrentRadioCard; 36 private final PagedListView mPresetList; 37 private final ValueAnimator mRemoveElevationAnimator; 38 39 public PresetListScrollListener(Context context, View container, View currentRadioCard, 40 PagedListView presetList) { 41 mPresetList = presetList; 42 mCurrentRadioCardContainer = container.findViewById(R.id.preset_current_card_container); 43 mCurrentRadioCard = currentRadioCard; 44 mContainerElevation = context.getResources() 45 .getDimension(R.dimen.car_preset_container_elevation); 46 47 mRemoveElevationAnimator = ValueAnimator.ofFloat(mContainerElevation, 0.f); 48 mRemoveElevationAnimator 49 .setDuration(ANIMATION_DURATION_MS) 50 .addUpdateListener(animation -> mCurrentRadioCardContainer.setElevation( 51 (float) animation.getAnimatedValue())); 52 } 53 54 @Override 55 public void onScrolled(RecyclerView recyclerView, int dx, int dy) { 56 if (mPresetList.getTranslationY() != 0.f) { 57 return; 58 } 59 60 if (mPresetList.getLayoutManager().isAtTop()) { 61 // Animate the removal of the elevation so that it's not jarring. 62 mRemoveElevationAnimator.start(); 63 } else { 64 // No animation needed when adding the elevation because the scroll masks the adding 65 // of the elevation. 66 mCurrentRadioCardContainer.setElevation(mContainerElevation); 67 mCurrentRadioCard.setTranslationZ(mContainerElevation); 68 } 69 } 70} 71