1 /* 2 * Copyright (C) 2015 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 17 package com.android.tv.guide; 18 19 import android.content.Context; 20 import android.support.v7.widget.LinearLayoutManager; 21 import android.support.v7.widget.RecyclerView; 22 import android.util.AttributeSet; 23 import android.view.View; 24 25 public class TimelineGridView extends RecyclerView { 26 public TimelineGridView(Context context) { 27 this(context, null); 28 } 29 30 public TimelineGridView(Context context, AttributeSet attrs) { 31 this(context, attrs, 0); 32 } 33 34 public TimelineGridView(Context context, AttributeSet attrs, int defStyle) { 35 super(context, attrs, defStyle); 36 37 setLayoutManager( 38 new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false) { 39 @Override 40 public boolean onRequestChildFocus( 41 RecyclerView parent, State state, View child, View focused) { 42 // This disables the default scroll behavior for focus movement. 43 return true; 44 } 45 }); 46 47 // RecyclerView is always focusable, however this is not desirable for us, so disable. 48 // See b/18863217 (ag/634046) for reasons to why RecyclerView is focusable. 49 setFocusable(false); 50 51 // Don't cache anything that is off screen. Normally it is good to prefetch and prepopulate 52 // off screen views in order to reduce jank, however the program guide is capable to scroll 53 // in all four directions so not only would we prefetch views in the scrolling direction 54 // but also keep views in the perpendicular direction up to date. 55 // E.g. when scrolling horizontally we would have to update rows above and below the current 56 // view port even though they are not visible. 57 setItemViewCacheSize(0); 58 } 59 } 60
