com.mycheez.adapter.DividerItemDecoration.java Source code

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Here is the source code for com.mycheez.adapter.DividerItemDecoration.java

Source

package com.mycheez.adapter;

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.content.ContextCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;

/*
 * 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 DividerItemDecoration extends RecyclerView.ItemDecoration {

    private Drawable mDivider;
    private boolean mShowFirstDivider = false;
    private boolean mShowLastDivider = false;

    int mOrientation = -1;
    int dividerLocation = 0;

    public DividerItemDecoration(Context context, AttributeSet attrs) {
        final TypedArray a = context.obtainStyledAttributes(attrs, new int[] { android.R.attr.listDivider });
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
            boolean showLastDivider) {
        this(context, attrs);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
    }

    public DividerItemDecoration(Context context, int resId) {
        mDivider = ContextCompat.getDrawable(context, resId);
    }

    public DividerItemDecoration(Context context, int resId, boolean showFirstDivider, boolean showLastDivider,
            int location) {
        this(context, resId);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
        dividerLocation = location;
    }

    public DividerItemDecoration(Drawable divider) {
        mDivider = divider;
    }

    public DividerItemDecoration(Drawable divider, boolean showFirstDivider, boolean showLastDivider) {
        this(divider);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        if (mDivider == null) {
            return;
        }

        int position = parent.getChildPosition(view);
        if (position == RecyclerView.NO_POSITION || (position == 0 && !mShowFirstDivider)) {
            return;
        }

        if (mOrientation == -1)
            getOrientation(parent);

        if (mOrientation == LinearLayoutManager.VERTICAL) {
            outRect.top = mDivider.getIntrinsicHeight();
            if (mShowLastDivider && position == (state.getItemCount() - 1)) {
                outRect.bottom = outRect.top;
            }
        } else {
            outRect.left = mDivider.getIntrinsicWidth();
            if (mShowLastDivider && position == (state.getItemCount() - 1)) {
                outRect.right = outRect.left;
            }
        }
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        if (mDivider == null) {
            super.onDrawOver(c, parent, state);
            return;
        }

        // Initialization needed to avoid compiler warning
        int left = 0, right = 0, top = 0, bottom = 0, size;
        int orientation = mOrientation != -1 ? mOrientation : getOrientation(parent);
        int childCount = parent.getChildCount();

        if (orientation == LinearLayoutManager.VERTICAL) {
            size = mDivider.getIntrinsicHeight();
            left = parent.getPaddingLeft();
            right = parent.getWidth() - parent.getPaddingRight();
        } else { //horizontal
            size = mDivider.getIntrinsicWidth();
            top = parent.getPaddingTop();
            bottom = parent.getHeight() - parent.getPaddingBottom();
        }

        for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
            View child = parent.getChildAt(i);
            int position = parent.getChildPosition(child);
            // Hack for showing the divider only for the position where friends list ends
            // Actual code :
            // https://gist.github.com/zokipirlo/82336d89249e05bba5aa
            if (dividerLocation == position) {
                RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
                if (orientation == LinearLayoutManager.VERTICAL) {
                    top = child.getTop() - params.topMargin - size;
                    bottom = top + size;
                } else { //horizontal
                    left = child.getLeft() - params.leftMargin;
                    right = left + size;
                }
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(c);
                break;
            }
        }

        // show last divider
        if (mShowLastDivider && childCount > 0) {
            View child = parent.getChildAt(childCount - 1);
            if (parent.getChildPosition(child) == (state.getItemCount() - 1)) {
                RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
                if (orientation == LinearLayoutManager.VERTICAL) {
                    top = child.getBottom() + params.bottomMargin;
                    bottom = top + size;
                } else { // horizontal
                    left = child.getRight() + params.rightMargin;
                    right = left + size;
                }
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(c);
            }
        }
    }

    private int getOrientation(RecyclerView parent) {
        if (mOrientation == -1) {
            if (parent.getLayoutManager() instanceof LinearLayoutManager) {
                LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
                mOrientation = layoutManager.getOrientation();
            } else {
                throw new IllegalStateException(
                        "DividerItemDecoration can only be used with a LinearLayoutManager.");
            }
        }
        return mOrientation;
    }
}