public class

HeadersFragment

extends androidx.leanback.app.BaseRowFragment

 java.lang.Object

↳Fragment

↳androidx.leanback.app.BaseRowFragment

↳androidx.leanback.app.HeadersFragment

Gradle dependencies

compile group: 'androidx.leanback', name: 'leanback', version: '1.2.0-alpha02'

  • groupId: androidx.leanback
  • artifactId: leanback
  • version: 1.2.0-alpha02

Artifact androidx.leanback:leanback:1.2.0-alpha02 it located at Google repository (https://maven.google.com/)

Androidx artifact mapping:

androidx.leanback:leanback com.android.support:leanback-v17

Androidx class mapping:

androidx.leanback.app.HeadersFragment android.support.v17.leanback.app.HeadersFragment

Overview

An fragment containing a list of row headers. Implementation must support three types of rows:

Use setPresenterSelector in subclass constructor to customize Presenters. App may override BrowseFragment.onCreateHeadersFragment().

Summary

Constructors
publicHeadersFragment()

Methods
public booleanisScrolling()

public voidonTransitionEnd()

public voidonTransitionStart()

public voidonViewCreated(View view, Bundle savedInstanceState)

public voidsetOnHeaderClickedListener(HeadersFragment.OnHeaderClickedListener listener)

public voidsetOnHeaderViewSelectedListener(HeadersFragment.OnHeaderViewSelectedListener listener)

from androidx.leanback.app.BaseRowFragmentgetAdapter, getBridgeAdapter, getPresenterSelector, getSelectedPosition, getVerticalGridView, onCreateView, onDestroyView, onSaveInstanceState, onTransitionPrepare, setAdapter, setAlignment, setPresenterSelector, setSelectedPosition, setSelectedPosition
from java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructors

public HeadersFragment()

Methods

public void setOnHeaderClickedListener(HeadersFragment.OnHeaderClickedListener listener)

public void setOnHeaderViewSelectedListener(HeadersFragment.OnHeaderViewSelectedListener listener)

public void onViewCreated(View view, Bundle savedInstanceState)

public void onTransitionStart()

public void onTransitionEnd()

public boolean isScrolling()

Source

// CHECKSTYLE:OFF Generated code
/* This file is auto-generated from HeadersSupportFragment.java.  DO NOT MODIFY. */

/*
 * 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 androidx.leanback.app;

import android.content.Context;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnLayoutChangeListener;
import android.view.ViewGroup;
import android.widget.FrameLayout;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.leanback.R;
import androidx.leanback.widget.ClassPresenterSelector;
import androidx.leanback.widget.DividerPresenter;
import androidx.leanback.widget.DividerRow;
import androidx.leanback.widget.FocusHighlightHelper;
import androidx.leanback.widget.HorizontalGridView;
import androidx.leanback.widget.ItemBridgeAdapter;
import androidx.leanback.widget.PresenterSelector;
import androidx.leanback.widget.Row;
import androidx.leanback.widget.RowHeaderPresenter;
import androidx.leanback.widget.SectionRow;
import androidx.leanback.widget.VerticalGridView;
import androidx.recyclerview.widget.RecyclerView;

/**
 * An fragment containing a list of row headers. Implementation must support three types of rows:
 * <ul>
 *     <li>{@link DividerRow} rendered by {@link DividerPresenter}.</li>
 *     <li>{@link Row} rendered by {@link RowHeaderPresenter}.</li>
 *     <li>{@link SectionRow} rendered by {@link RowHeaderPresenter}.</li>
 * </ul>
 * Use {@link #setPresenterSelector(PresenterSelector)} in subclass constructor to customize
 * Presenters. App may override {@link BrowseFragment#onCreateHeadersFragment()}.
 * @deprecated use {@link HeadersSupportFragment}
 */
@Deprecated
public class HeadersFragment extends BaseRowFragment {

    /**
     * Interface definition for a callback to be invoked when a header item is clicked.
     * @deprecated use {@link HeadersSupportFragment}
     */
    @Deprecated
    public interface OnHeaderClickedListener {
        /**
         * Called when a header item has been clicked.
         *
         * @param viewHolder Row ViewHolder object corresponding to the selected Header.
         * @param row Row object corresponding to the selected Header.
         */
        void onHeaderClicked(RowHeaderPresenter.ViewHolder viewHolder, Row row);
    }

    /**
     * Interface definition for a callback to be invoked when a header item is selected.
     * @deprecated use {@link HeadersSupportFragment}
     */
    @Deprecated
    public interface OnHeaderViewSelectedListener {
        /**
         * Called when a header item has been selected.
         *
         * @param viewHolder Row ViewHolder object corresponding to the selected Header.
         * @param row Row object corresponding to the selected Header.
         */
        void onHeaderSelected(RowHeaderPresenter.ViewHolder viewHolder, Row row);
    }

    private OnHeaderViewSelectedListener mOnHeaderViewSelectedListener;
    OnHeaderClickedListener mOnHeaderClickedListener;
    private boolean mHeadersEnabled = true;
    private boolean mHeadersGone = false;
    private int mBackgroundColor;
    private boolean mBackgroundColorSet;

    private static final PresenterSelector sHeaderPresenter = new ClassPresenterSelector()
            .addClassPresenter(DividerRow.class, new DividerPresenter())
            .addClassPresenter(SectionRow.class,
                    new RowHeaderPresenter(R.layout.lb_section_header, false))
            .addClassPresenter(Row.class, new RowHeaderPresenter(R.layout.lb_header));

    public HeadersFragment() {
        setPresenterSelector(sHeaderPresenter);
        FocusHighlightHelper.setupHeaderItemFocusHighlight(getBridgeAdapter());
    }

    public void setOnHeaderClickedListener(OnHeaderClickedListener listener) {
        mOnHeaderClickedListener = listener;
    }

    public void setOnHeaderViewSelectedListener(OnHeaderViewSelectedListener listener) {
        mOnHeaderViewSelectedListener = listener;
    }

    @Override
    VerticalGridView findGridViewFromRoot(View view) {
        return (VerticalGridView) view.findViewById(R.id.browse_headers);
    }

    @Override
    void onRowSelected(RecyclerView parent, RecyclerView.ViewHolder viewHolder,
            int position, int subposition) {
        if (mOnHeaderViewSelectedListener != null) {
            if (viewHolder != null && position >= 0) {
                ItemBridgeAdapter.ViewHolder vh = (ItemBridgeAdapter.ViewHolder) viewHolder;
                mOnHeaderViewSelectedListener.onHeaderSelected(
                        (RowHeaderPresenter.ViewHolder) vh.getViewHolder(), (Row) vh.getItem());
            } else {
                mOnHeaderViewSelectedListener.onHeaderSelected(null, null);
            }
        }
    }

    private final ItemBridgeAdapter.AdapterListener mAdapterListener =
            new ItemBridgeAdapter.AdapterListener() {
        @Override
        public void onCreate(final ItemBridgeAdapter.ViewHolder viewHolder) {
            View headerView = viewHolder.getViewHolder().view;
            headerView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (mOnHeaderClickedListener != null) {
                        mOnHeaderClickedListener.onHeaderClicked(
                                (RowHeaderPresenter.ViewHolder) viewHolder.getViewHolder(),
                                (Row) viewHolder.getItem());
                    }
                }
            });
            if (mWrapper != null) {
                viewHolder.itemView.addOnLayoutChangeListener(sLayoutChangeListener);
            } else {
                headerView.addOnLayoutChangeListener(sLayoutChangeListener);
            }
        }

    };

    static OnLayoutChangeListener sLayoutChangeListener = new OnLayoutChangeListener() {
        @Override
        public void onLayoutChange(View v, int left, int top, int right, int bottom,
            int oldLeft, int oldTop, int oldRight, int oldBottom) {
            v.setPivotX(v.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL ? v.getWidth() : 0);
            v.setPivotY(v.getMeasuredHeight() / 2);
        }
    };

    @Override
    int getLayoutResourceId() {
        return R.layout.lb_headers_fragment;
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        final VerticalGridView listView = getVerticalGridView();
        if (listView == null) {
            return;
        }
        if (mBackgroundColorSet) {
            listView.setBackgroundColor(mBackgroundColor);
            updateFadingEdgeToBrandColor(mBackgroundColor);
        } else {
            Drawable d = listView.getBackground();
            if (d instanceof ColorDrawable) {
                updateFadingEdgeToBrandColor(((ColorDrawable) d).getColor());
            }
        }
        updateListViewVisibility();
    }

    private void updateListViewVisibility() {
        final VerticalGridView listView = getVerticalGridView();
        if (listView != null) {
            getView().setVisibility(mHeadersGone ? View.GONE : View.VISIBLE);
            if (!mHeadersGone) {
                if (mHeadersEnabled) {
                    listView.setChildrenVisibility(View.VISIBLE);
                } else {
                    listView.setChildrenVisibility(View.INVISIBLE);
                }
            }
        }
    }

    void setHeadersEnabled(boolean enabled) {
        mHeadersEnabled = enabled;
        updateListViewVisibility();
    }

    void setHeadersGone(boolean gone) {
        mHeadersGone = gone;
        updateListViewVisibility();
    }

    static class NoOverlappingFrameLayout extends FrameLayout {

        public NoOverlappingFrameLayout(Context context) {
            super(context);
        }

        /**
         * Avoid creating hardware layer for header dock.
         */
        @Override
        public boolean hasOverlappingRendering() {
            return false;
        }
    }

    // Wrapper needed because of conflict between RecyclerView's use of alpha
    // for ADD animations, and RowHeaderPresenter's use of alpha for selected level.
    final ItemBridgeAdapter.Wrapper mWrapper = new ItemBridgeAdapter.Wrapper() {
        @Override
        public void wrap(View wrapper, View wrapped) {
            ((FrameLayout) wrapper).addView(wrapped);
        }

        @Override
        public View createWrapper(View root) {
            return new NoOverlappingFrameLayout(root.getContext());
        }
    };
    @Override
    void updateAdapter() {
        super.updateAdapter();
        ItemBridgeAdapter adapter = getBridgeAdapter();
        adapter.setAdapterListener(mAdapterListener);
        adapter.setWrapper(mWrapper);
    }

    void setBackgroundColor(int color) {
        mBackgroundColor = color;
        mBackgroundColorSet = true;

        if (getVerticalGridView() != null) {
            getVerticalGridView().setBackgroundColor(mBackgroundColor);
            updateFadingEdgeToBrandColor(mBackgroundColor);
        }
    }

    private void updateFadingEdgeToBrandColor(int backgroundColor) {
        View fadingView = getView().findViewById(R.id.fade_out_edge);
        Drawable background = fadingView.getBackground();
        if (background instanceof GradientDrawable) {
            background.mutate();
            ((GradientDrawable) background).setColors(
                    new int[] {Color.TRANSPARENT, backgroundColor});
        }
    }

    @Override
    public void onTransitionStart() {
        super.onTransitionStart();
        if (!mHeadersEnabled) {
            // When enabling headers fragment,  the RowHeaderView gets a focus but
            // isShown() is still false because its parent is INVISIBLE, accessibility
            // event is not sent.
            // Workaround is: prevent focus to a child view during transition and put
            // focus on it after transition is done.
            final VerticalGridView listView = getVerticalGridView();
            if (listView != null) {
                listView.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
                if (listView.hasFocus()) {
                    listView.requestFocus();
                }
            }
        }
    }

    @Override
    public void onTransitionEnd() {
        if (mHeadersEnabled) {
            final VerticalGridView listView = getVerticalGridView();
            if (listView != null) {
                listView.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
                if (listView.hasFocus()) {
                    listView.requestFocus();
                }
            }
        }
        super.onTransitionEnd();
    }

    public boolean isScrolling() {
        return getVerticalGridView().getScrollState()
                != HorizontalGridView.SCROLL_STATE_IDLE;
    }
}