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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.supportv7.widget.decorator;
     18 
     19 import android.content.Context;
     20 import android.content.res.TypedArray;
     21 import android.graphics.Canvas;
     22 import android.graphics.Rect;
     23 import android.graphics.drawable.Drawable;
     24 import android.support.v4.view.ViewCompat;
     25 import android.support.v7.widget.LinearLayoutManager;
     26 import android.support.v7.widget.RecyclerView;
     27 import android.view.View;
     28 
     29 public class DividerItemDecoration extends RecyclerView.ItemDecoration {
     30 
     31     private static final int[] ATTRS = new int[]{
     32             android.R.attr.listDivider
     33     };
     34 
     35     public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
     36 
     37     public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
     38 
     39     private Drawable mDivider;
     40 
     41     private int mOrientation;
     42 
     43     public DividerItemDecoration(Context context, int orientation) {
     44         final TypedArray a = context.obtainStyledAttributes(ATTRS);
     45         mDivider = a.getDrawable(0);
     46         a.recycle();
     47         setOrientation(orientation);
     48     }
     49 
     50     public void setOrientation(int orientation) {
     51         if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
     52             throw new IllegalArgumentException("invalid orientation");
     53         }
     54         mOrientation = orientation;
     55     }
     56 
     57     @Override
     58     public void onDraw(Canvas c, RecyclerView parent) {
     59         if (mOrientation == VERTICAL_LIST) {
     60             drawVertical(c, parent);
     61         } else {
     62             drawHorizontal(c, parent);
     63         }
     64     }
     65 
     66     public void drawVertical(Canvas c, RecyclerView parent) {
     67         final int left = parent.getPaddingLeft();
     68         final int right = parent.getWidth() - parent.getPaddingRight();
     69 
     70         final int childCount = parent.getChildCount();
     71         for (int i = 0; i < childCount; i++) {
     72             final View child = parent.getChildAt(i);
     73             final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
     74                     .getLayoutParams();
     75             final int top = child.getBottom() + params.bottomMargin +
     76                     Math.round(ViewCompat.getTranslationY(child));
     77             final int bottom = top + mDivider.getIntrinsicHeight();
     78             mDivider.setBounds(left, top, right, bottom);
     79             mDivider.draw(c);
     80         }
     81     }
     82 
     83     public void drawHorizontal(Canvas c, RecyclerView parent) {
     84         final int top = parent.getPaddingTop();
     85         final int bottom = parent.getHeight() - parent.getPaddingBottom();
     86 
     87         final int childCount = parent.getChildCount();
     88         for (int i = 0; i < childCount; i++) {
     89             final View child = parent.getChildAt(i);
     90             final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
     91                     .getLayoutParams();
     92             final int left = child.getRight() + params.rightMargin +
     93                     Math.round(ViewCompat.getTranslationX(child));
     94             final int right = left + mDivider.getIntrinsicHeight();
     95             mDivider.setBounds(left, top, right, bottom);
     96             mDivider.draw(c);
     97         }
     98     }
     99 
    100     @Override
    101     public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
    102         if (mOrientation == VERTICAL_LIST) {
    103             outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
    104         } else {
    105             outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
    106         }
    107     }
    108 }
    109