src/com/android/documentsui/dirlist/InputHandlers.java

/*
 * Copyright (C) 2017 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.documentsui.dirlist;

import static androidx.core.util.Preconditions.checkArgument;

import android.view.KeyEvent;

import androidx.recyclerview.selection.SelectionTracker;
import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.ViewHolder;

import com.android.documentsui.ActionHandler;

/**
 * Helper class dedicated to building gesture input handlers. The construction
 * of the various input handlers is non trivial. To keep logic clear,
 * code flexible, and DirectoryFragment small(er), the construction has been
 * isolated here in a separate class.
 */
final class InputHandlers {

    private ActionHandler mActions;
    private SelectionTracker<String> mSelectionHelper;
    private SelectionPredicate<String> mSelectionPredicate;
    private FocusHandler mFocusHandler;
    private RecyclerView mRecView;

    InputHandlers(
            ActionHandler actions,
            SelectionTracker<String> selectionHelper,
            SelectionPredicate<String> selectionPredicate,
            FocusHandler focusHandler,
            RecyclerView recView) {

        checkArgument(actions != null);
        checkArgument(selectionHelper != null);
        checkArgument(selectionPredicate != null);
        checkArgument(focusHandler != null);
        checkArgument(recView != null);

        mActions = actions;
        mSelectionHelper = selectionHelper;
        mSelectionPredicate = selectionPredicate;
        mFocusHandler = focusHandler;
        mRecView = recView;
    }

    KeyInputHandler createKeyHandler() {
        KeyInputHandler.Callbacks<DocumentItemDetails> callbacks =
                new KeyInputHandler.Callbacks<DocumentItemDetails>() {
            @Override
            public boolean isInteractiveItem(DocumentItemDetails item, KeyEvent e) {
                switch (item.getItemViewType()) {
                    case DocumentsAdapter.ITEM_TYPE_HEADER_MESSAGE:
                    case DocumentsAdapter.ITEM_TYPE_INFLATED_MESSAGE:
                    case DocumentsAdapter.ITEM_TYPE_SECTION_BREAK:
                        return false;
                    case DocumentsAdapter.ITEM_TYPE_DOCUMENT:
                    case DocumentsAdapter.ITEM_TYPE_DIRECTORY:
                        return true;
                    default:
                        throw new RuntimeException(
                                "Unsupported item type: " + item.getItemViewType());
                }
            }

            @Override
            public boolean onItemActivated(DocumentItemDetails item, KeyEvent e) {
                // Handle enter key events
                switch (e.getKeyCode()) {
                    case KeyEvent.KEYCODE_ENTER:
                    case KeyEvent.KEYCODE_DPAD_CENTER:
                    case KeyEvent.KEYCODE_BUTTON_A:
                        return mActions.openItem(
                                item,
                                ActionHandler.VIEW_TYPE_REGULAR,
                                ActionHandler.VIEW_TYPE_PREVIEW);
                    case KeyEvent.KEYCODE_SPACE:
                        return mActions.openItem(
                                item,
                                ActionHandler.VIEW_TYPE_PREVIEW,
                                ActionHandler.VIEW_TYPE_NONE);
                }

                return false;
            }

            @Override
            public boolean onFocusItem(DocumentItemDetails details, int keyCode, KeyEvent event) {
                ViewHolder holder =
                        mRecView.findViewHolderForAdapterPosition(details.getPosition());
                if (holder instanceof DocumentHolder) {
                    return mFocusHandler.handleKey((DocumentHolder) holder, keyCode, event);
                }
                return false;
            }
        };

        return new KeyInputHandler(mSelectionHelper, mSelectionPredicate, callbacks);
    }
}