com.pachong.android.baseuicomponent.DividerItemDecoration.java Source code

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Here is the source code for com.pachong.android.baseuicomponent.DividerItemDecoration.java

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/*
 * 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 com.pachong.android.baseuicomponent;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ViewCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;

import com.pachong.android.baseuicomponent.adapter.RecyclerViewBaseAdapter;

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private static final int[] ATTRS = new int[] { android.R.attr.listDivider };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private Drawable mDivider;

    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }

    public void drawVertical(Canvas c, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            if (!shouldDrawItemAt(parent, i)) {
                continue;
            }
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin + Math.round(ViewCompat.getTranslationY(child));
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            if (!shouldDrawItemAt(parent, i)) {
                continue;
            }
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int left = child.getRight() + params.rightMargin + Math.round(ViewCompat.getTranslationX(child));
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        //Add for ignore header view and footer view offsets
        if (!shouldDrawItemAtAdapterPosi(parent, itemPosition)) {
            outRect.set(0, 0, 0, 0);
            return;
        }
        //End added

        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }

    /**
     * ??draw item
     * e.g headerview  footerview?item decoration
     * 
     * @param itemPosi
     *            ?? layout position, not adapter position
     * @return
     */
    private boolean shouldDrawItemAt(RecyclerView parent, int itemPosi) {
        RecyclerView.ViewHolder vh = parent.getChildViewHolder(parent.getChildAt(itemPosi));
        if (vh instanceof RecyclerViewBaseAdapter.HeaderViewHolder) {
            //return false;
        }
        return !(vh instanceof RecyclerViewBaseAdapter.LoadingViewHolder);
    }

    /**
     * ??draw item
     * e.g headerview  footerview?item decoration
     * 
     * @param itemPosi
     *            ??adapter position, not layout position
     * @return
     */
    private boolean shouldDrawItemAtAdapterPosi(RecyclerView parent, int itemPosi) {
        RecyclerView.Adapter adapter = parent.getAdapter();
        if (adapter != null && adapter instanceof RecyclerViewBaseAdapter) {
            RecyclerViewBaseAdapter rvBaseAdapter = (RecyclerViewBaseAdapter) adapter;
            if (itemPosi == 0 && rvBaseAdapter.hasHeaderView()) {
                //return false;
            }
            if (itemPosi == rvBaseAdapter.getItemCount() - 1 && rvBaseAdapter.hasLoadingLayout()) {
                return false;
            }
        }
        return true;
    }
}