src/com/android/tv/guide/TimelineGridView.java

/*
 * Copyright (C) 2015 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 com.android.tv.guide;

import android.content.Context;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;

public class TimelineGridView extends RecyclerView {
    public TimelineGridView(Context context) {
        this(context, null);
    }

    public TimelineGridView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public TimelineGridView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        setLayoutManager(
                new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false) {
                    @Override
                    public boolean onRequestChildFocus(
                            RecyclerView parent, State state, View child, View focused) {
                        // This disables the default scroll behavior for focus movement.
                        return true;
                    }
                });

        // RecyclerView is always focusable, however this is not desirable for us, so disable.
        // See b/18863217 (ag/634046) for reasons to why RecyclerView is focusable.
        setFocusable(false);

        // Don't cache anything that is off screen. Normally it is good to prefetch and prepopulate
        // off screen views in order to reduce jank, however the program guide is capable to scroll
        // in all four directions so not only would we prefetch views in the scrolling direction
        // but also keep views in the perpendicular direction up to date.
        // E.g. when scrolling horizontally we would have to update rows above and below the current
        // view port even though they are not visible.
        setItemViewCacheSize(0);
    }
}