com.wj.recyclerviewdemo.decorator.DividerItemDecoration.java Source code

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Here is the source code for com.wj.recyclerviewdemo.decorator.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.wj.recyclerviewdemo.decorator;

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.RecyclerView;
import android.view.View;

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
    public static final int TYPE_LIST = 1;
    public static final int TYPE_GRID = 2;
    private int mType;
    private Drawable mDivider;

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

    public void setType(int type) {
        if (type != TYPE_GRID && type != TYPE_LIST) {
            throw new IllegalArgumentException("invalid type");
        }
        mType = type;
    }

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

    public void drawHorizontal(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++) {
            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 drawVertical(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++) {
            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) {
        if (mType == TYPE_GRID) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        } else if (mType == TYPE_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        }
    }
}