src/com/android/launcher3/widget/WidgetsListAdapter.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.launcher3.widget;

import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;

import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.Adapter;

import com.android.launcher3.R;
import com.android.launcher3.WidgetPreviewLoader;
import com.android.launcher3.icons.IconCache;
import com.android.launcher3.model.WidgetItem;
import com.android.launcher3.util.LabelComparator;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 * List view adapter for the widget tray.
 *
 * <p>Memory vs. Performance:
 * The less number of types of views are inserted into a {@link RecyclerView}, the more recycling
 * happens and less memory is consumed. {@link #getItemViewType} was not overridden as there is
 * only a single type of view.
 */
public class WidgetsListAdapter extends Adapter<WidgetsRowViewHolder> {

    private static final String TAG = "WidgetsListAdapter";
    private static final boolean DEBUG = false;

    private final WidgetPreviewLoader mWidgetPreviewLoader;
    private final LayoutInflater mLayoutInflater;

    private final OnClickListener mIconClickListener;
    private final OnLongClickListener mIconLongClickListener;
    private final int mIndent;
    private ArrayList<WidgetListRowEntry> mEntries = new ArrayList<>();
    private final WidgetsDiffReporter mDiffReporter;

    private boolean mApplyBitmapDeferred;

    public WidgetsListAdapter(Context context, LayoutInflater layoutInflater,
            WidgetPreviewLoader widgetPreviewLoader, IconCache iconCache,
            OnClickListener iconClickListener, OnLongClickListener iconLongClickListener) {
        mLayoutInflater = layoutInflater;
        mWidgetPreviewLoader = widgetPreviewLoader;
        mIconClickListener = iconClickListener;
        mIconLongClickListener = iconLongClickListener;
        mIndent = context.getResources().getDimensionPixelSize(R.dimen.widget_section_indent);
        mDiffReporter = new WidgetsDiffReporter(iconCache, this);
    }

    /**
     * Defers applying bitmap on all the {@link WidgetCell} in the {@param rv}
     *
     * @see WidgetCell#setApplyBitmapDeferred(boolean)
     */
    public void setApplyBitmapDeferred(boolean isDeferred, RecyclerView rv) {
        mApplyBitmapDeferred = isDeferred;

        for (int i = rv.getChildCount() - 1; i >= 0; i--) {
            WidgetsRowViewHolder holder = (WidgetsRowViewHolder)
                    rv.getChildViewHolder(rv.getChildAt(i));
            for (int j = holder.cellContainer.getChildCount() - 1; j >= 0; j--) {
                View v = holder.cellContainer.getChildAt(j);
                if (v instanceof WidgetCell) {
                    ((WidgetCell) v).setApplyBitmapDeferred(mApplyBitmapDeferred);
                }
            }
        }
    }

    /**
     * Update the widget list.
     */
    public void setWidgets(ArrayList<WidgetListRowEntry> tempEntries) {
        WidgetListRowEntryComparator rowComparator = new WidgetListRowEntryComparator();
        Collections.sort(tempEntries, rowComparator);
        mDiffReporter.process(mEntries, tempEntries, rowComparator);
    }

    @Override
    public int getItemCount() {
        return mEntries.size();
    }

    public String getSectionName(int pos) {
        return mEntries.get(pos).titleSectionName;
    }

    @Override
    public void onBindViewHolder(WidgetsRowViewHolder holder, int pos) {
        WidgetListRowEntry entry = mEntries.get(pos);
        List<WidgetItem> infoList = entry.widgets;

        ViewGroup row = holder.cellContainer;
        if (DEBUG) {
            Log.d(TAG, String.format(
                    "onBindViewHolder [pos=%d, widget#=%d, row.getChildCount=%d]",
                    pos, infoList.size(), row.getChildCount()));
        }

        // Add more views.
        // if there are too many, hide them.
        int expectedChildCount = infoList.size() + Math.max(0, infoList.size() - 1);
        int childCount = row.getChildCount();

        if (expectedChildCount > childCount) {
            for (int i = childCount; i < expectedChildCount; i++) {
                if ((i & 1) == 1) {
                    // Add a divider for odd index
                    mLayoutInflater.inflate(R.layout.widget_list_divider, row);
                } else {
                    // Add cell for even index
                    WidgetCell widget = (WidgetCell) mLayoutInflater.inflate(
                            R.layout.widget_cell, row, false);

                    // set up touch.
                    widget.setOnClickListener(mIconClickListener);
                    widget.setOnLongClickListener(mIconLongClickListener);
                    row.addView(widget);
                }
            }
        } else if (expectedChildCount < childCount) {
            for (int i = expectedChildCount; i < childCount; i++) {
                row.getChildAt(i).setVisibility(View.GONE);
            }
        }

        // Bind the views in the application info section.
        holder.title.applyFromItemInfoWithIcon(entry.pkgItem);

        // Bind the view in the widget horizontal tray region.
        for (int i = 0; i < infoList.size(); i++) {
            WidgetCell widget = (WidgetCell) row.getChildAt(2 * i);
            widget.applyFromCellItem(infoList.get(i), mWidgetPreviewLoader);
            widget.setApplyBitmapDeferred(mApplyBitmapDeferred);
            widget.ensurePreview();
            widget.setVisibility(View.VISIBLE);

            if (i > 0) {
                row.getChildAt(2 * i - 1).setVisibility(View.VISIBLE);
            }
        }
    }

    @Override
    public WidgetsRowViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (DEBUG) {
            Log.v(TAG, "\nonCreateViewHolder");
        }

        ViewGroup container = (ViewGroup) mLayoutInflater.inflate(
                R.layout.widgets_list_row_view, parent, false);

        // if the end padding is 0, then container view (horizontal scroll view) doesn't respect
        // the end of the linear layout width + the start padding and doesn't allow scrolling.
        container.findViewById(R.id.widgets_cell_list).setPaddingRelative(mIndent, 0, 1, 0);

        return new WidgetsRowViewHolder(container);
    }

    @Override
    public void onViewRecycled(WidgetsRowViewHolder holder) {
        int total = holder.cellContainer.getChildCount();
        for (int i = 0; i < total; i += 2) {
            WidgetCell widget = (WidgetCell) holder.cellContainer.getChildAt(i);
            widget.clear();
        }
    }

    public boolean onFailedToRecycleView(WidgetsRowViewHolder holder) {
        // If child views are animating, then the RecyclerView may choose not to recycle the view,
        // causing extraneous onCreateViewHolder() calls.  It is safe in this case to continue
        // recycling this view, and take care in onViewRecycled() to cancel any existing
        // animations.
        return true;
    }

    @Override
    public long getItemId(int pos) {
        return pos;
    }

    /**
     * Comparator for sorting WidgetListRowEntry based on package title
     */
    public static class WidgetListRowEntryComparator implements Comparator<WidgetListRowEntry> {

        private final LabelComparator mComparator = new LabelComparator();

        @Override
        public int compare(WidgetListRowEntry a, WidgetListRowEntry b) {
            return mComparator.compare(a.pkgItem.title.toString(), b.pkgItem.title.toString());
        }
    }
}