package com.android.app_base.widget;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.view.LayoutInflater;
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import android.view.View;
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import android.view.ViewGroup;
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import android.view.ViewParent;
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import androidx.annotation.LayoutRes;
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import androidx.annotation.NonNull;
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import androidx.annotation.Nullable;
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import androidx.recyclerview.widget.GridLayoutManager;
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import androidx.recyclerview.widget.RecyclerView;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* 支持添加底部和头部的 RecyclerView
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*/
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public final class WrapRecyclerView extends RecyclerView {
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/**
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* 原有的适配器
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*/
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private Adapter mRealAdapter;
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/**
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* 支持添加头部和底部的适配器
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*/
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private final WrapRecyclerAdapter mWrapAdapter = new WrapRecyclerAdapter();
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public WrapRecyclerView(Context context) {
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super(context);
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}
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public WrapRecyclerView(Context context, @Nullable AttributeSet attrs) {
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super(context, attrs);
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}
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public WrapRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
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super(context, attrs, defStyle);
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}
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@Override
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public void setAdapter(Adapter adapter) {
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mRealAdapter = adapter;
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// 偷梁换柱
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mWrapAdapter.setRealAdapter(mRealAdapter);
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// 禁用条目动画
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setItemAnimator(null);
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super.setAdapter(mWrapAdapter);
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}
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@Override
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public Adapter getAdapter() {
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return mRealAdapter;
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}
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/**
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* 添加头部View
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*/
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public void addHeaderView(View view) {
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mWrapAdapter.addHeaderView(view);
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}
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@SuppressWarnings("unchecked")
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public <V extends View> V addHeaderView(@LayoutRes int id) {
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View headerView = LayoutInflater.from(getContext()).inflate(id, this, false);
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addHeaderView(headerView);
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return (V) headerView;
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}
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/**
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* 移除头部View
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*/
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public void removeHeaderView(View view) {
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mWrapAdapter.removeHeaderView(view);
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}
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/**
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* 添加底部View
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*/
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public void addFooterView(View view) {
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mWrapAdapter.addFooterView(view);
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}
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@SuppressWarnings("unchecked")
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public <V extends View> V addFooterView(@LayoutRes int id) {
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View footerView = LayoutInflater.from(getContext()).inflate(id, this, false);
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addFooterView(footerView);
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return (V) footerView;
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}
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/**
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* 移除底部View
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*/
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public void removeFooterView(View view) {
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mWrapAdapter.removeFooterView(view);
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}
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/**
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* 获取头部View总数
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*/
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public int getHeaderViewsCount() {
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return mWrapAdapter.getHeaderViewsCount();
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}
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/**
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* 获取底部View总数
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*/
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public int getFooterViewsCount() {
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return mWrapAdapter.getFooterViewsCount();
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}
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/**
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* 获取头部View集合
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*/
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public List<View> getHeaderViews() {
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return mWrapAdapter.getHeaderViews();
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}
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/**
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* 获取底部View集合
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*/
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public List<View> getFooterViews() {
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return mWrapAdapter.getFooterViews();
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}
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/**
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* 刷新头部和底部布局所有的 View 的状态
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*/
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public void refreshHeaderFooterViews() {
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mWrapAdapter.notifyDataSetChanged();
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}
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/**
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* 设置在 GridLayoutManager 模式下头部和尾部都是独占一行的效果
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*/
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public void adjustSpanSize() {
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final LayoutManager layoutManager = getLayoutManager();
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if (layoutManager instanceof GridLayoutManager) {
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((GridLayoutManager) layoutManager).setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
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@Override
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public int getSpanSize(int position) {
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return (position < mWrapAdapter.getHeaderViewsCount()
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|| position >= mWrapAdapter.getHeaderViewsCount() + (mRealAdapter == null ? 0 : mRealAdapter.getItemCount()))
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? ((GridLayoutManager) layoutManager).getSpanCount() : 1;
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}
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});
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}
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}
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/**
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* 采用装饰设计模式，将原有的适配器包装起来
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*/
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private static final class WrapRecyclerAdapter extends Adapter<ViewHolder> {
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/**
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* 头部条目类型
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*/
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private static final int HEADER_VIEW_TYPE = Integer.MIN_VALUE >> 1;
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/**
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* 底部条目类型
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*/
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private static final int FOOTER_VIEW_TYPE = Integer.MAX_VALUE >> 1;
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/**
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* 原有的适配器
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*/
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private Adapter mRealAdapter;
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/**
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* 头部View集合
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*/
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private final List<View> mHeaderViews = new ArrayList<>();
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/**
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* 底部View集合
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*/
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private final List<View> mFooterViews = new ArrayList<>();
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/**
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* 当前调用的位置
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*/
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private int mCurrentPosition;
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/**
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* RecyclerView对象
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*/
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private RecyclerView mRecyclerView;
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/**
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* 数据观察者对象
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*/
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private WrapAdapterDataObserver mObserver;
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private void setRealAdapter(Adapter adapter) {
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if (mRealAdapter != adapter) {
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if (mRealAdapter != null) {
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if (mObserver != null) {
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// 为原有的RecyclerAdapter移除数据监听对象
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mRealAdapter.unregisterAdapterDataObserver(mObserver);
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}
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}
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mRealAdapter = adapter;
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if (mRealAdapter != null) {
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if (mObserver == null) {
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mObserver = new WrapAdapterDataObserver(this);
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}
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// 为原有的RecyclerAdapter添加数据监听对象
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mRealAdapter.registerAdapterDataObserver(mObserver);
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// 适配器不是第一次被绑定到RecyclerView上需要发送通知，因为第一次绑定会自动通知
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if (mRecyclerView != null) {
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notifyDataSetChanged();
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}
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}
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}
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}
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@Override
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public int getItemCount() {
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if (mRealAdapter != null) {
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return getHeaderViewsCount() + mRealAdapter.getItemCount() + getFooterViewsCount();
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} else {
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return getHeaderViewsCount() + getFooterViewsCount();
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}
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}
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@SuppressWarnings("all")
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@Override
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public int getItemViewType(int position) {
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mCurrentPosition = position;
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// 获取头部布局的总数
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int headerCount = getHeaderViewsCount();
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// 获取原有适配器的总数
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int adapterCount = mRealAdapter != null ? mRealAdapter.getItemCount() : 0;
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// 获取在原有适配器上的位置
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int adjPosition = position - headerCount;
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if (position < headerCount) {
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return HEADER_VIEW_TYPE;
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} else if (adjPosition < adapterCount) {
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return mRealAdapter.getItemViewType(adjPosition);
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} else {
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return FOOTER_VIEW_TYPE;
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}
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}
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public int getPosition() {
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return mCurrentPosition;
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}
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@SuppressWarnings("all")
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@Override
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public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
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switch (viewType) {
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case HEADER_VIEW_TYPE:
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return newWrapViewHolder(mHeaderViews.get(getPosition()));
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case FOOTER_VIEW_TYPE:
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return newWrapViewHolder(mFooterViews.get(getPosition() - getHeaderViewsCount() - (mRealAdapter != null ? mRealAdapter.getItemCount() : 0)));
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default:
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int itemViewType = mRealAdapter.getItemViewType(getPosition() - getHeaderViewsCount());
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if (itemViewType == HEADER_VIEW_TYPE || itemViewType == FOOTER_VIEW_TYPE) {
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throw new IllegalStateException("Please do not use this type as itemType");
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}
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if (mRealAdapter != null) {
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return mRealAdapter.onCreateViewHolder(parent, itemViewType);
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} else {
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return null;
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}
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}
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}
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@SuppressWarnings("unchecked")
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@Override
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public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
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int viewType = getItemViewType(position);
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switch (viewType) {
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case HEADER_VIEW_TYPE:
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case FOOTER_VIEW_TYPE:
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break;
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default:
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if (mRealAdapter != null) {
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mRealAdapter.onBindViewHolder(holder, getPosition() - getHeaderViewsCount());
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}
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break;
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}
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}
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private WrapViewHolder newWrapViewHolder(View view) {
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ViewParent parent = view.getParent();
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if (parent instanceof ViewGroup) {
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// IllegalStateException: ViewHolder views must not be attached when created.
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// Ensure that you are not passing 'true' to the attachToRoot parameter of LayoutInflater.inflate(..., boolean attachToRoot)
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((ViewGroup) parent).removeView(view);
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}
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return new WrapViewHolder(view);
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}
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@Override
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public long getItemId(int position) {
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if (mRealAdapter != null && position > getHeaderViewsCount() - 1 && position < getHeaderViewsCount() + mRealAdapter.getItemCount()) {
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return mRealAdapter.getItemId(position - getHeaderViewsCount());
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} else {
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return super.getItemId(position);
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}
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}
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@Override
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public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
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mRecyclerView = recyclerView;
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if (mRealAdapter != null) {
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mRealAdapter.onAttachedToRecyclerView(recyclerView);
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}
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}
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@Override
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public void onDetachedFromRecyclerView(@NonNull RecyclerView recyclerView) {
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mRecyclerView = null;
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if (mRealAdapter != null) {
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mRealAdapter.onDetachedFromRecyclerView(recyclerView);
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}
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}
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@SuppressWarnings("unchecked")
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@Override
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public void onViewRecycled(@NonNull ViewHolder holder) {
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if (holder instanceof WrapViewHolder) {
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// 防止这个 ViewHolder 被 RecyclerView 拿去复用
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holder.setIsRecyclable(false);
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return;
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}
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if (mRealAdapter != null) {
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mRealAdapter.onViewRecycled(holder);
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}
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}
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@SuppressWarnings("unchecked")
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@Override
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public boolean onFailedToRecycleView(@NonNull ViewHolder holder) {
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if (mRealAdapter != null) {
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return mRealAdapter.onFailedToRecycleView(holder);
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}
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return super.onFailedToRecycleView(holder);
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}
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@SuppressWarnings("unchecked")
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@Override
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public void onViewAttachedToWindow(@NonNull ViewHolder holder) {
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if (mRealAdapter != null) {
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mRealAdapter.onViewAttachedToWindow(holder);
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}
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}
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@SuppressWarnings("unchecked")
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@Override
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public void onViewDetachedFromWindow(@NonNull ViewHolder holder) {
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if (mRealAdapter != null) {
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mRealAdapter.onViewDetachedFromWindow(holder);
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}
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}
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/**
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* 添加头部View
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*/
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private void addHeaderView(View view) {
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// 不能添加同一个View对象，否则会导致RecyclerView复用异常
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if (!mHeaderViews.contains(view) && !mFooterViews.contains(view)) {
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mHeaderViews.add(view);
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notifyDataSetChanged();
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}
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}
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/**
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* 移除头部View
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*/
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private void removeHeaderView(View view) {
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if (mHeaderViews.remove(view)) {
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notifyDataSetChanged();
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}
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}
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/**
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* 添加底部View
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*/
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private void addFooterView(View view) {
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// 不能添加同一个View对象，否则会导致RecyclerView复用异常
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if (!mFooterViews.contains(view) && !mHeaderViews.contains(view)) {
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mFooterViews.add(view);
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notifyDataSetChanged();
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}
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}
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/**
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* 移除底部View
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*/
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private void removeFooterView(View view) {
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if (mFooterViews.remove(view)) {
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notifyDataSetChanged();
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}
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}
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/**
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* 获取头部View总数
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*/
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private int getHeaderViewsCount() {
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return mHeaderViews.size();
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}
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/**
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* 获取底部View总数
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*/
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private int getFooterViewsCount() {
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return mFooterViews.size();
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}
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/**
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* 获取头部View集合
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*/
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private List<View> getHeaderViews() {
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return mHeaderViews;
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}
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/**
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* 获取底部View集合
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*/
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private List<View> getFooterViews() {
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return mFooterViews;
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}
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}
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/**
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* 头部和底部通用的ViewHolder对象
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*/
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private static final class WrapViewHolder extends ViewHolder {
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private WrapViewHolder(View itemView) {
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super(itemView);
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}
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}
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/**
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* 数据改变监听器
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*/
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private static final class WrapAdapterDataObserver extends AdapterDataObserver {
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private final WrapRecyclerAdapter mWrapAdapter;
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private WrapAdapterDataObserver(WrapRecyclerAdapter adapter) {
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mWrapAdapter = adapter;
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}
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@Override
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public void onChanged() {
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mWrapAdapter.notifyDataSetChanged();
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}
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@Override
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public void onItemRangeChanged(int positionStart, int itemCount, Object payload) {
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onItemRangeChanged(mWrapAdapter.getHeaderViewsCount() + positionStart, itemCount);
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}
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@Override
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public void onItemRangeChanged(int positionStart, int itemCount) {
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mWrapAdapter.notifyItemRangeChanged(mWrapAdapter.getHeaderViewsCount() + positionStart, itemCount);
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}
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@Override
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public void onItemRangeInserted(int positionStart, int itemCount) {
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mWrapAdapter.notifyItemRangeInserted(mWrapAdapter.getHeaderViewsCount() + positionStart, itemCount);
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}
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@Override
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public void onItemRangeRemoved(int positionStart, int itemCount) {
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mWrapAdapter.notifyItemRangeRemoved(mWrapAdapter.getHeaderViewsCount() + positionStart, itemCount);
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}
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@Override
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public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
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mWrapAdapter.notifyItemMoved(mWrapAdapter.getHeaderViewsCount() + fromPosition, toPosition);
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}
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}
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}
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