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@sebnapi
Last active August 30, 2015 20:06
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/*
* Copyright (C) 2014 sebnapi
*
* 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.
*/
import android.support.v7.widget.RecyclerView;
import android.view.ViewGroup;
/**
* Created by sebnapi on 08.11.14.
* <p/>
* This is a Plug-and-Play Approach for adding a Header or Footer to
* a RecyclerView backed list
* <p/>
* Just wrap your regular adapter like this
* <p/>
* new HeaderRecyclerViewAdapterV1(new RegularAdapter())
* <p/>
* Let RegularAdapter implement HeaderRecyclerView, FooterRecyclerView or both
* and you are ready to go.
* <p/>
* I'm absolutely not sure how this will behave with changes in the dataset.
* You can always wrap a fresh adapter and make sure to not change the old one or
* use my other approach.
* <p/>
* With the other approach you need to let your Adapter extend HeaderRecyclerViewAdapterV2
* (and therefore change potentially more code) but possible omit these shortcomings.
* <p/>
* TOTALLY UNTESTED - USE WITH CARE - HAVE FUN :)
*/
public class HeaderRecyclerViewAdapterV1 extends RecyclerView.Adapter {
private static final int TYPE_HEADER = Integer.MIN_VALUE;
private static final int TYPE_FOOTER = Integer.MIN_VALUE + 1;
private static final int TYPE_ADAPTEE_OFFSET = 2;
private final RecyclerView.Adapter mAdaptee;
public HeaderRecyclerViewAdapterV1(RecyclerView.Adapter adaptee) {
mAdaptee = adaptee;
}
public RecyclerView.Adapter getAdaptee() {
return mAdaptee;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_HEADER && mAdaptee instanceof HeaderRecyclerView) {
return ((HeaderRecyclerView) mAdaptee).onCreateHeaderViewHolder(parent, viewType);
} else if (viewType == TYPE_FOOTER && mAdaptee instanceof FooterRecyclerView) {
return ((FooterRecyclerView) mAdaptee).onCreateFooterViewHolder(parent, viewType);
}
return mAdaptee.onCreateViewHolder(parent, viewType - TYPE_ADAPTEE_OFFSET);
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (position == 0 && holder.getItemViewType() == TYPE_HEADER && useHeader()) {
((HeaderRecyclerView) mAdaptee).onBindHeaderView(holder, position);
} else if (position == mAdaptee.getItemCount() && holder.getItemViewType() == TYPE_FOOTER && useFooter()) {
((FooterRecyclerView) mAdaptee).onBindFooterView(holder, position);
} else {
mAdaptee.onBindViewHolder(holder, position - (useHeader() ? 1 : 0));
}
}
@Override
public int getItemCount() {
int itemCount = mAdaptee.getItemCount();
if (useHeader()) {
itemCount += 1;
}
if (useFooter()) {
itemCount += 1;
}
return itemCount;
}
private boolean useHeader() {
if (mAdaptee instanceof HeaderRecyclerView) {
return true;
}
return false;
}
private boolean useFooter() {
if (mAdaptee instanceof FooterRecyclerView) {
return true;
}
return false;
}
@Override
public int getItemViewType(int position) {
if (position == 0 && useHeader()) {
return TYPE_HEADER;
}
if (position == mAdaptee.getItemCount() && useFooter()) {
return TYPE_FOOTER;
}
if (mAdaptee.getItemCount() >= Integer.MAX_VALUE - TYPE_ADAPTEE_OFFSET) {
new IllegalStateException("HeaderRecyclerViewAdapter offsets your BasicItemType by " + TYPE_ADAPTEE_OFFSET + ".");
}
return mAdaptee.getItemViewType(position) + TYPE_ADAPTEE_OFFSET;
}
public static interface HeaderRecyclerView {
public RecyclerView.ViewHolder onCreateHeaderViewHolder(ViewGroup parent, int viewType);
public void onBindHeaderView(RecyclerView.ViewHolder holder, int position);
}
public static interface FooterRecyclerView {
public RecyclerView.ViewHolder onCreateFooterViewHolder(ViewGroup parent, int viewType);
public void onBindFooterView(RecyclerView.ViewHolder holder, int position);
}
}
@ishaangarg
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How can I add a textview in onBindHeaderView implementation inside the regular adapter? Basically, I need to update the textview inside the header.

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