AccountDividerItemDecoration.java

package de.geeksfactory.opacclient.ui;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.RecyclerView;
import android.view.View;

import de.geeksfactory.opacclient.R;
import de.geeksfactory.opacclient.frontend.adapter.AccountAdapter;
import su.j2e.rvjoiner.RvJoiner;

/*
 * 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.
 */
public class AccountDividerItemDecoration extends RecyclerView.ItemDecoration {
    private Drawable mDividerWithInset;
    private Drawable mDividerWithoutInset;
    private RvJoiner rvJoiner;

    public AccountDividerItemDecoration(Context context, RvJoiner rvJoiner) {
        mDividerWithInset = ContextCompat.getDrawable(context, R.drawable.list_divider_inset);
        mDividerWithoutInset = ContextCompat.getDrawable(context, R.drawable.list_divider);
        this.rvJoiner = rvJoiner;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.ViewHolder vh = parent.getChildViewHolder(child);

            if (!isDecorated(child, parent)) continue;
            if (!(vh instanceof AccountAdapter.ViewHolder)) continue;


            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;

            final Drawable drawable = (
                    ((AccountAdapter.ViewHolder) vh).isCoversHidden()
                            ? mDividerWithoutInset
                            : mDividerWithInset
            );
            final int bottom = top + drawable.getIntrinsicHeight();
            drawable.setBounds(left, top, right, bottom);
            drawable.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView
            .State state) {
        if (isDecorated(view, parent)) {
            outRect.set(0, 0, 0, mDividerWithInset.getIntrinsicHeight());
        }
    }

    private boolean isDecorated(View view, RecyclerView parent) {
        RecyclerView.ViewHolder vh = parent.getChildViewHolder(view);

        if (rvJoiner != null) {
            if (vh instanceof AccountAdapter.ViewHolder) {
                RvJoiner.PositionInfo pi =
                        rvJoiner.getPositionInfo(parent.getChildAdapterPosition(view));
                return (pi != null && pi.joinable.getAdapter() instanceof AccountAdapter
                        && pi.realPosition < pi.joinable.getAdapter().getItemCount() - 1);
            }
            return true;
        } else {
            View nextView = parent.getChildAt(parent.getChildAdapterPosition(view) + 1);
            if (nextView != null) {
                RecyclerView.ViewHolder vh2 = parent.getChildViewHolder(nextView);
                return vh instanceof AccountAdapter.ViewHolder &&
                        vh2 instanceof AccountAdapter.ViewHolder;
            }
        }
        return false;
    }
}