Hello i`m trying to get recyclerview viewholder at particular position with this code:
val viewHolder = educationRv.findViewHolderForAdapterPosition(i) as SectionsRecyclerAdapter.ViewHolder
the problem is that recycler view recycle not visible items and i can't get item and position 0 if its not visible. I searched before ask i tried this solutions, but can't prevent recycling of the views (i know that this is not good solution but i`m stuck and can't figure it out better) :
educationRv.recycledViewPool.setMaxRecycledViews(1,0)
override fun getItemViewType(position: Int): Int {
return 1
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
if (holder != null) {
holder.setIsRecyclable(false)
}
Generalized -> i have recyclerview with 20 edittexts which can be added dynamically, when user click save i need to get all edittexts values and save it to array, the problem comes when button save is clicked only two or three views are visible when i try to get not visible return null
As i got your query this solution would definitely help you
In you viewHolder do like this
etText.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
yourEditTextList.set(getAdapterPosition(), s.toString());
}
#Override
public void afterTextChanged(Editable s) {
}
});
btnAddNewEditText.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
yourEditTextList.add(new String(""));
notifyDataSetChanged();
}
});
Here yourEditTextList is the list of String in of your editText in your recylerView
In your activity where you have recylerView
btnDone.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Fetch you list that your have passed on recycler view you will get here
}
});
I have ImageView inside of an item in a RecyclerView. Every time I click on an item, I want the image to become visible and the previous clicked item's image becomes invisible.
public static class MyHolder extends RecyclerView.ViewHolder {
private ImageView image_view;
private TextView text_view_name;
private TextView text_view_abilities;
private ImageView heart_image_view;
public MyHolder(#NonNull final View itemView, final OnItemClickListener listener) {
super(itemView);
image_view = itemView.findViewById(R.id.image_view);
text_view_name = itemView.findViewById(R.id.text_view_name);
text_view_abilities = itemView.findViewById(R.id.text_view_abilities);
heart_image_view = itemView.findViewById(R.id.heart_image_view);
heart_image_view.setImageResource(R.drawable.heart);
heart_image_view.setVisibility(View.GONE);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
listener.onItemClick(position);
heart_image_view.setVisibility(View.VISIBLE);
}
}
});
}
}
#NonNull
#Override
public MyHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.single_item_layout, viewGroup, false);
MyHolder holder = new MyHolder(v, mlistener);
return holder;
}
#Override
public void onBindViewHolder(#NonNull MyHolder myHolder, int position) {
Item item = myList.get(position);
myHolder.text_view_name.setText(item.getTitle());
stringArray = item.getAbilitiesObj();
StringBuilder builder = new StringBuilder();
for (int i = 0; i < stringArray.size(); i++) {
try {
builder.append(stringArray.get(i));
builder.append(", ");
} catch (NumberFormatException ex) {
ex.printStackTrace();
}
myHolder.text_view_abilities.setText(builder);
}
if (myHolder.image_view != null) {
String photoUrl = item.getImageUrl();
Picasso.with(mContext).load(photoUrl).into(myHolder.image_view);
}
}
In MyHolder class where item.setOnClick, I set the clicked item image visible but then every time I click on another item, the image of the new item becomes visible and the image of the previous item does not get invisible.
You need to have another array of integers in your adapter to keep track of the items which is clicked. At first, initialize the array of integers with all ones.
// Define an array like the following in your adapter
private int[] selectedItems = new int[yourDataList.size()]; // Initialize the array to have the same size as your data list.
Then initialize the array with all ones. Try having a function like this in your adapter.
private void initializeSeledtedItems() {
for(int item : selectedItems) item = 1;
}
Now in your onBindViewHolder, set the visibility of the ImageView in your RecyclerView items based on the value found in the selectedItems array.
if(selectedItems[position] == 1) heart_image_view.setVisibility(View.VISIBLE);
else heart_image_view.setVisibility(View.GONE);
In the onClickListener modify the selectedItems array as such that, only the item selected has the value one and all the others have zeros. Then call notifyDataSetChanged to take your changes into effect.
private void setSelectedItem(int position) {
for(int i = 0; i < selectedItems.length(); i++) {
if(i == position) selectedItems[i] = 1;
else selectedItems[i] = 0;
}
}
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
setSelectedItem(position);
notifyDataSetChanged();
}
}
}
});
Hope that helps!
My code is for setting Visibility on recycler view's item , when you click on recycler views item it set VISIBLE on that particular item and INVISIBLE on other items.
this code works for me for setting visibility on clicked item and hiding previous icon.
initialize
int selecteditem =0;
onBindViewHolder
if(selecteditem==position){
holder.icSelect.setVisibility(View.VISIBLE);
}
else{
holder.icSelect.setVisibility(View.INVISIBLE);
}
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
selecteditem=position;
holder.icselect.setVisibility(View.VISIBLE);
notifyDataSetChanged();
}
});
i uploaded image for basic idea .
enter image description here
I'm trying to use ItemDecorator to add some separators into a RecyclerView. This is the fragment of the code that does it.
//...
public abstract C onInflateViewHolder(Context ctx);
public abstract void onBindViewHolder(C holder, int index);
#Override
public void onDraw(Canvas c, RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
public void drawVertical(Canvas c, RecyclerView parent) {
final int left = parent.getPaddingLeft();
final int right = parent.getWidth() - parent.getPaddingRight();
for (int i = 0; i < parent.getChildCount(); i++) {
C view = onInflateViewHolder(mContext);
onBindViewHolder(view, i);
RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
//parent.addView(view.itemView, i, p);
view.itemView.draw(c);
}
}
//...
As you can see I tried using parent.addView(view.itemView, i, p);, parent.addView(view.itemView, i); and finally view.itemView.draw(c);.
This is the implementations:
mItemDecorator =
new GenericDecorator<ChatDateSeparatorViewHolder>(getActivity(), GenericDecorator.VERTICAL_LIST) {
#Override
public ChatDateSeparatorViewHolder onInflateViewHolder(Context ctx) {
View v = LayoutInflater.from(ctx).inflate(R.layout.chat_message_separator, null);
return new ChatDateSeparatorViewHolder(v);
}
#Override
public void onBindViewHolder(ChatDateSeparatorViewHolder holder, int index) {
if (index < mAdapter.getItemCount()-1) {
ChatMessage previous = mAdapter.getMessage(index);
ChatMessage current = mAdapter.getMessage(index+1);
long startTime = previous.getSendDate().getTime();
long endTime = current.getSendDate().getTime();
long diffTime = endTime - startTime;
long diffDays = diffTime / (1000 * 60 * 60 * 24);
if (diffDays > 0) {
holder.text.setText(Converters.format(current.getSendDate(), getActivity()));
} else {
holder.root.setVisibility(View.GONE);
}
} else {
holder.root.setVisibility(View.GONE);
}
}
};
By the way, C is a Recycler.ViewHolder, as you can see in the implementation.
All seems to be fine but It crashes when tries to add the views. The exceptions that I did get was NullpointerException when I used the addView with the LayoutParams ad at android.support.v7.widget.RecyclerView$LayoutParams.getViewPosition(RecyclerView.java:6957)
I just need to know how add programatically a View into a RecyclerView without using an adapter.
EDIT:
I'm trying to add separators in a RecyclerView, this separators will be views that I get from a ViewHolder, it's everything done, the only thing that I need to know is how add, programatically, the view (that I get from my ViewHolder) into the RecyclerView
Here is a screenshot of the mockup of the app, so you will have a better idea:
The line that says "Hoy" (today in spanish) is one of the separators.
You can do this by using your item View's tag
In your Adapter's onBindViewHolder, you can determine whether or not this was the last message for the day. If it was the last message of the day, then you can call something like holder.itemView.setTag("isLastForDay").
Then in your decorator, while looping through your RecyclerView's children, read each child's tag. If the tag contains "isLastForDay", then execute your "hoy" drawing logic.
This is how i frequently do this
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
recyclerView.setLayoutManager(layoutManager);
RecycleMarginDecoration recycleMarginDecoration = new RecycleMarginDecoration(this);
recyclerView.addItemDecoration(recycleMarginDecoration);
Add Decorator Class
public class RecycleMarginDecoration extends RecyclerView.ItemDecoration {
private int margin;
public RecycleMarginDecoration(Context context) {
/* Assign value from xml whatever you want to make as margin*/
margin = context.getResources().getDimensionPixelSize(R.dimen.padding_four);
}
#Override
public void getItemOffsets(
Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
outRect.set(margin, margin / 2, margin / 2, 0);
}
}
I spent a moment trying to figure out a way to add a header to a RecyclerView, unsuccessfully.
This is what I got so far:
#Override
protected void onCreate(Bundle savedInstanceState) {
...
layouManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layouManager);
LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
headerPlaceHolder = inflater.inflate(R.layout.view_header_holder_medium, null, false);
layouManager.addView(headerPlaceHolder, 0);
...
}
The LayoutManager seems to be the object handling the disposition of the RecyclerView items. As I couldn't find any addHeaderView(View view) method, I decided to go with the LayoutManager's addView(View view, int position) method and to add my header view in the first position to act as a header.
Aaand this is where things get uglier:
java.lang.NullPointerException: Attempt to read from field 'android.support.v7.widget.RecyclerView$ViewHolder android.support.v7.widget.RecyclerView$LayoutParams.mViewHolder' on a null object reference
at android.support.v7.widget.RecyclerView.getChildViewHolderInt(RecyclerView.java:2497)
at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:4807)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:4803)
at com.mathieumaree.showz.fragments.CategoryFragment.setRecyclerView(CategoryFragment.java:231)
at com.mathieumaree.showz.fragments.CategoryFragment.access$200(CategoryFragment.java:47)
at com.mathieumaree.showz.fragments.CategoryFragment$2.success(CategoryFragment.java:201)
at com.mathieumaree.showz.fragments.CategoryFragment$2.success(CategoryFragment.java:196)
at retrofit.CallbackRunnable$1.run(CallbackRunnable.java:41)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
After getting several NullPointerExceptions trying to call the addView(View view) at different moments of the Activity creation (also tried adding the view once everything is set up, even the Adapter's data), I realized I have no idea if this is the right way to do it (and it doesn't look to be).
PS: Also, a solution that could handle the GridLayoutManager in addition to the LinearLayoutManager would be really appreciated!
I had to add a footer to my RecyclerView and here I'm sharing my code snippet as I thought it might be useful. Please check the comments inside the code for better understanding of the overall flow.
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
public class RecyclerViewWithFooterAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int FOOTER_VIEW = 1;
private ArrayList<String> data; // Take any list that matches your requirement.
private Context context;
// Define a constructor
public RecyclerViewWithFooterAdapter(Context context, ArrayList<String> data) {
this.context = context;
this.data = data;
}
// Define a ViewHolder for Footer view
public class FooterViewHolder extends ViewHolder {
public FooterViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do whatever you want on clicking the item
}
});
}
}
// Now define the ViewHolder for Normal list item
public class NormalViewHolder extends ViewHolder {
public NormalViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do whatever you want on clicking the normal items
}
});
}
}
// And now in onCreateViewHolder you have to pass the correct view
// while populating the list item.
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v;
if (viewType == FOOTER_VIEW) {
v = LayoutInflater.from(context).inflate(R.layout.list_item_footer, parent, false);
FooterViewHolder vh = new FooterViewHolder(v);
return vh;
}
v = LayoutInflater.from(context).inflate(R.layout.list_item_normal, parent, false);
NormalViewHolder vh = new NormalViewHolder(v);
return vh;
}
// Now bind the ViewHolder in onBindViewHolder
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
try {
if (holder instanceof NormalViewHolder) {
NormalViewHolder vh = (NormalViewHolder) holder;
vh.bindView(position);
} else if (holder instanceof FooterViewHolder) {
FooterViewHolder vh = (FooterViewHolder) holder;
}
} catch (Exception e) {
e.printStackTrace();
}
}
// Now the critical part. You have return the exact item count of your list
// I've only one footer. So I returned data.size() + 1
// If you've multiple headers and footers, you've to return total count
// like, headers.size() + data.size() + footers.size()
#Override
public int getItemCount() {
if (data == null) {
return 0;
}
if (data.size() == 0) {
//Return 1 here to show nothing
return 1;
}
// Add extra view to show the footer view
return data.size() + 1;
}
// Now define getItemViewType of your own.
#Override
public int getItemViewType(int position) {
if (position == data.size()) {
// This is where we'll add footer.
return FOOTER_VIEW;
}
return super.getItemViewType(position);
}
// So you're done with adding a footer and its action on onClick.
// Now set the default ViewHolder for NormalViewHolder
public class ViewHolder extends RecyclerView.ViewHolder {
// Define elements of a row here
public ViewHolder(View itemView) {
super(itemView);
// Find view by ID and initialize here
}
public void bindView(int position) {
// bindView() method to implement actions
}
}
}
The above code snippet adds a footer to the RecyclerView. You can check this GitHub repository for checking the implementation of adding both header and a footer.
Very simple to solve!!
I don't like an idea of having logic inside adapter as a different view type because every time it checks for the view type before returning the view. Below solution avoids extra checks.
Just add LinearLayout (vertical) header view + recyclerview + footer view inside android.support.v4.widget.NestedScrollView.
Check this out:
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<View
android:id="#+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<android.support.v7.widget.RecyclerView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="LinearLayoutManager"/>
<View
android:id="#+id/footer"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
Add this line of code for smooth scrolling
RecyclerView v = (RecyclerView) findViewById(...);
v.setNestedScrollingEnabled(false);
This will lose all RV performance and RV will try to lay out all view holders regardless of the layout_height of RV
Recommended using for the small size list like Nav drawer or settings etc.
I had the same problem on Lollipop and created two approaches to wrap the Recyclerview adapter. One is pretty easy to use, but I'm not sure how it will behave with a changing dataset. Because it wraps your adapter and you need to make yourself sure to call methods like notifyDataSetChanged on the right adapter-object.
The other shouldn't have such problems. Just let your regular adapter extend the class, implement the abstract methods and you should be ready. And here they are:
gists
HeaderRecyclerViewAdapterV1.java usage new HeaderRecyclerViewAdapterV1(new RegularAdapter());
HeaderRecyclerViewAdapterV2.java usage RegularAdapter extends HeaderRecyclerViewAdapterV2
HeaderRecyclerViewAdapterV1
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);
}
}
HeaderRecyclerViewAdapterV2
import android.support.v7.widget.RecyclerView;
import android.view.ViewGroup;
/**
* Created by sebnapi on 08.11.14.
* <p/>
* If you extend this Adapter you are able to add a Header, a Footer or both
* by a similar ViewHolder pattern as in RecyclerView.
* <p/>
* If you want to omit changes to your class hierarchy you can try the Plug-and-Play
* approach HeaderRecyclerViewAdapterV1.
* <p/>
* Don't override (Be careful while overriding)
* - onCreateViewHolder
* - onBindViewHolder
* - getItemCount
* - getItemViewType
* <p/>
* You need to override the abstract methods introduced by this class. This class
* is not using generics as RecyclerView.Adapter make yourself sure to cast right.
* <p/>
* TOTALLY UNTESTED - USE WITH CARE - HAVE FUN :)
*/
public abstract class HeaderRecyclerViewAdapterV2 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;
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_HEADER) {
return onCreateHeaderViewHolder(parent, viewType);
} else if (viewType == TYPE_FOOTER) {
return onCreateFooterViewHolder(parent, viewType);
}
return onCreateBasicItemViewHolder(parent, viewType - TYPE_ADAPTEE_OFFSET);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (position == 0 && holder.getItemViewType() == TYPE_HEADER) {
onBindHeaderView(holder, position);
} else if (position == getBasicItemCount() && holder.getItemViewType() == TYPE_FOOTER) {
onBindFooterView(holder, position);
} else {
onBindBasicItemView(holder, position - (useHeader() ? 1 : 0));
}
}
#Override
public int getItemCount() {
int itemCount = getBasicItemCount();
if (useHeader()) {
itemCount += 1;
}
if (useFooter()) {
itemCount += 1;
}
return itemCount;
}
#Override
public int getItemViewType(int position) {
if (position == 0 && useHeader()) {
return TYPE_HEADER;
}
if (position == getBasicItemCount() && useFooter()) {
return TYPE_FOOTER;
}
if (getBasicItemType(position) >= Integer.MAX_VALUE - TYPE_ADAPTEE_OFFSET) {
new IllegalStateException("HeaderRecyclerViewAdapter offsets your BasicItemType by " + TYPE_ADAPTEE_OFFSET + ".");
}
return getBasicItemType(position) + TYPE_ADAPTEE_OFFSET;
}
public abstract boolean useHeader();
public abstract RecyclerView.ViewHolder onCreateHeaderViewHolder(ViewGroup parent, int viewType);
public abstract void onBindHeaderView(RecyclerView.ViewHolder holder, int position);
public abstract boolean useFooter();
public abstract RecyclerView.ViewHolder onCreateFooterViewHolder(ViewGroup parent, int viewType);
public abstract void onBindFooterView(RecyclerView.ViewHolder holder, int position);
public abstract RecyclerView.ViewHolder onCreateBasicItemViewHolder(ViewGroup parent, int viewType);
public abstract void onBindBasicItemView(RecyclerView.ViewHolder holder, int position);
public abstract int getBasicItemCount();
/**
* make sure you don't use [Integer.MAX_VALUE-1, Integer.MAX_VALUE] as BasicItemViewType
*
* #param position
* #return
*/
public abstract int getBasicItemType(int position);
}
Feedback and forks appreciated. I will use HeaderRecyclerViewAdapterV2 by my self and evolve, test and post the changes in the future.
EDIT: #OvidiuLatcu Yes I had some problems. Actually I stopped offsetting the Header implicitly by position - (useHeader() ? 1 : 0) and instead created a public method int offsetPosition(int position) for it. Because if you set an OnItemTouchListener on Recyclerview, you can intercept the touch, get the x,y coordinates of the touch, find the according child view and then call recyclerView.getChildPosition(...)and you will always get the non-offsetted position in the adapter! This is a shortcomming in the RecyclerView Code, I don't see an easy method to overcome this. This is why I now offset the positions explicit when I need to by my own code.
I haven't tried this, but I would simply add 1 (or 2, if you want both a header and footer) to the integer returned by getItemCount in your adapter. You can then override getItemViewType in your adapter to return a different integer when i==0: https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html#getItemViewType(int)
createViewHolder is then passed the integer you returned from getItemViewType, allowing you to create or configure the view holder differently for the header view: https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html#createViewHolder(android.view.ViewGroup, int)
Don't forget to subtract one from the position integer passed to bindViewHolder.
You can used this GitHub library allowing to add Header and/or Footer in your RecyclerView in the simplest way possible.
You need to add HFRecyclerView library in your project or you can also grab it from Gradle:
compile 'com.mikhaellopez:hfrecyclerview:1.0.0'
This is a result in image:
EDIT:
If you just want to add a margin at the top and/or bottom with this library: SimpleItemDecoration:
int offsetPx = 10;
recyclerView.addItemDecoration(new StartOffsetItemDecoration(offsetPx));
recyclerView.addItemDecoration(new EndOffsetItemDecoration(offsetPx));
I ended up implementing my own adapter to wrap any other adapter and provide methods to add header and footer views.
Created a gist here: HeaderViewRecyclerAdapter.java
The main feature I wanted was a similar interface to a ListView, so I wanted to be able to inflate the views in my Fragment and add them to the RecyclerView in onCreateView. This is done by creating a HeaderViewRecyclerAdapter passing the adapter to be wrapped, and calling addHeaderView and addFooterView passing your inflated views. Then set the HeaderViewRecyclerAdapter instance as the adapter on the RecyclerView.
An extra requirement was that I needed to be able to easily swap out adapters while keeping the headers and footers, I didn't want to have multiple adapters with multiple instances of these headers and footers. So you can call setAdapter to change the wrapped adapter leaving the headers and footers intact, with the RecyclerView being notified of the change.
recyclerview:1.2.0 introduces ConcatAdapter class which concatenates multiple adapters into a single one. So it allows to create separate header/footer adapters and reuse them across multiple lists.
myRecyclerView.adapter = ConcatAdapter(headerAdapter, listAdapter, footerAdapter)
Take a look at the announcement article. It contains a sample how to display a loading progress in header and footer using ConcatAdapter.
For the moment when I post this answer the version 1.2.0 of the library is in alpha stage, so the api might change. You can check the status here.
my "keep it simple stupid" way ...it waste some resources , i know , but i dont care as my code keep simple
so...
First, add a footer with visibility GONE to your item_layout
<LinearLayout
android:id="#+id/footer"
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="vertical"
android:visibility="gone">
</LinearLayout>
Then, set it visible on the last item
public void onBindViewHolder(ChannelAdapter.MyViewHolder holder, int position) {
boolean last = position==data.size()-1;
//....
holder.footer.setVisibility(View.GONE);
if (last && showFooter){
holder.footer.setVisibility(View.VISIBLE);
}
}
do the opposite for header
Based on #seb's solution, I created a subclass of RecyclerView.Adapter that supports an arbitrary number of headers and footers.
https://gist.github.com/mheras/0908873267def75dc746
Although it seems to be a solution, I also think this thing should be managed by the LayoutManager. Unfortunately, I need it now and I don't have time to implement a StaggeredGridLayoutManager from scratch (nor even extend from it).
I'm still testing it, but you can try it out if you want. Please let me know if you find any issues with it.
You can use viewtype to solve this problem, here is my demo:
https://github.com/yefengfreedom/RecyclerViewWithHeaderFooterLoadingEmptyViewErrorView
you can define some recycler view display mode:
public static final int MODE_DATA = 0, MODE_LOADING = 1, MODE_ERROR = 2, MODE_EMPTY = 3, MODE_HEADER_VIEW = 4, MODE_FOOTER_VIEW = 5;
2.override the getItemViewType mothod
#Override
public int getItemViewType(int position) {
if (mMode == RecyclerViewMode.MODE_LOADING) {
return RecyclerViewMode.MODE_LOADING;
}
if (mMode == RecyclerViewMode.MODE_ERROR) {
return RecyclerViewMode.MODE_ERROR;
}
if (mMode == RecyclerViewMode.MODE_EMPTY) {
return RecyclerViewMode.MODE_EMPTY;
}
//check what type our position is, based on the assumption that the order is headers > items > footers
if (position < mHeaders.size()) {
return RecyclerViewMode.MODE_HEADER_VIEW;
} else if (position >= mHeaders.size() + mData.size()) {
return RecyclerViewMode.MODE_FOOTER_VIEW;
}
return RecyclerViewMode.MODE_DATA;
}
3.override the getItemCount method
#Override
public int getItemCount() {
if (mMode == RecyclerViewMode.MODE_DATA) {
return mData.size() + mHeaders.size() + mFooters.size();
} else {
return 1;
}
}
4.override the onCreateViewHolder method. create view holder by viewType
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == RecyclerViewMode.MODE_LOADING) {
RecyclerView.ViewHolder loadingViewHolder = onCreateLoadingViewHolder(parent);
loadingViewHolder.itemView.setLayoutParams(
new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, parent.getHeight() - mToolBarHeight)
);
return loadingViewHolder;
}
if (viewType == RecyclerViewMode.MODE_ERROR) {
RecyclerView.ViewHolder errorViewHolder = onCreateErrorViewHolder(parent);
errorViewHolder.itemView.setLayoutParams(
new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, parent.getHeight() - mToolBarHeight)
);
errorViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
if (null != mOnErrorViewClickListener) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mOnErrorViewClickListener.onErrorViewClick(v);
}
}, 200);
}
}
});
return errorViewHolder;
}
if (viewType == RecyclerViewMode.MODE_EMPTY) {
RecyclerView.ViewHolder emptyViewHolder = onCreateEmptyViewHolder(parent);
emptyViewHolder.itemView.setLayoutParams(
new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, parent.getHeight() - mToolBarHeight)
);
emptyViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
if (null != mOnEmptyViewClickListener) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mOnEmptyViewClickListener.onEmptyViewClick(v);
}
}, 200);
}
}
});
return emptyViewHolder;
}
if (viewType == RecyclerViewMode.MODE_HEADER_VIEW) {
RecyclerView.ViewHolder headerViewHolder = onCreateHeaderViewHolder(parent);
headerViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
if (null != mOnHeaderViewClickListener) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mOnHeaderViewClickListener.onHeaderViewClick(v, v.getTag());
}
}, 200);
}
}
});
return headerViewHolder;
}
if (viewType == RecyclerViewMode.MODE_FOOTER_VIEW) {
RecyclerView.ViewHolder footerViewHolder = onCreateFooterViewHolder(parent);
footerViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
if (null != mOnFooterViewClickListener) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mOnFooterViewClickListener.onFooterViewClick(v, v.getTag());
}
}, 200);
}
}
});
return footerViewHolder;
}
RecyclerView.ViewHolder dataViewHolder = onCreateDataViewHolder(parent);
dataViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
if (null != mOnItemClickListener) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mOnItemClickListener.onItemClick(v, v.getTag());
}
}, 200);
}
}
});
dataViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(final View v) {
if (null != mOnItemLongClickListener) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mOnItemLongClickListener.onItemLongClick(v, v.getTag());
}
}, 200);
return true;
}
return false;
}
});
return dataViewHolder;
}
5.Override the onBindViewHolder method. bind data by viewType
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (mMode == RecyclerViewMode.MODE_LOADING) {
onBindLoadingViewHolder(holder, position);
} else if (mMode == RecyclerViewMode.MODE_ERROR) {
onBindErrorViewHolder(holder, position);
} else if (mMode == RecyclerViewMode.MODE_EMPTY) {
onBindEmptyViewHolder(holder, position);
} else {
if (position < mHeaders.size()) {
if (mHeaders.size() > 0) {
onBindHeaderViewHolder(holder, position);
}
} else if (position >= mHeaders.size() + mData.size()) {
if (mFooters.size() > 0) {
onBindFooterViewHolder(holder, position - mHeaders.size() - mData.size());
}
} else {
onBindDataViewHolder(holder, position - mHeaders.size());
}
}
}
You can use the library SectionedRecyclerViewAdapter to group your items in sections and add a header to each section, like on the image below:
First you create your section class:
class MySection extends StatelessSection {
String title;
List<String> list;
public MySection(String title, List<String> list) {
// call constructor with layout resources for this Section header, footer and items
super(R.layout.section_header, R.layout.section_item);
this.title = title;
this.list = list;
}
#Override
public int getContentItemsTotal() {
return list.size(); // number of items of this section
}
#Override
public RecyclerView.ViewHolder getItemViewHolder(View view) {
// return a custom instance of ViewHolder for the items of this section
return new MyItemViewHolder(view);
}
#Override
public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
MyItemViewHolder itemHolder = (MyItemViewHolder) holder;
// bind your view here
itemHolder.tvItem.setText(list.get(position));
}
#Override
public RecyclerView.ViewHolder getHeaderViewHolder(View view) {
return new SimpleHeaderViewHolder(view);
}
#Override
public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder) {
MyHeaderViewHolder headerHolder = (MyHeaderViewHolder) holder;
// bind your header view here
headerHolder.tvItem.setText(title);
}
}
Then you set up the RecyclerView with your sections and change the SpanSize of the headers with a GridLayoutManager:
// Create an instance of SectionedRecyclerViewAdapter
SectionedRecyclerViewAdapter sectionAdapter = new SectionedRecyclerViewAdapter();
// Create your sections with the list of data
MySection section1 = new MySection("My Section 1 title", dataList1);
MySection section2 = new MySection("My Section 2 title", dataList2);
// Add your Sections to the adapter
sectionAdapter.addSection(section1);
sectionAdapter.addSection(section2);
// Set up a GridLayoutManager to change the SpanSize of the header
GridLayoutManager glm = new GridLayoutManager(getContext(), 2);
glm.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
#Override
public int getSpanSize(int position) {
switch(sectionAdapter.getSectionItemViewType(position)) {
case SectionedRecyclerViewAdapter.VIEW_TYPE_HEADER:
return 2;
default:
return 1;
}
}
});
// Set up your RecyclerView with the SectionedRecyclerViewAdapter
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(glm);
recyclerView.setAdapter(sectionAdapter);
I would just add an alternative to all those HeaderRecyclerViewAdapter implementation. CompoundAdapter:
https://github.com/negusoft/CompoundAdapter-android
It is a more flexible approach, since you can create a AdapterGroup out of Adapters. For the header example, use your adapter as it is, along with an adapter containing one item for the header:
AdapterGroup adapterGroup = new AdapterGroup();
adapterGroup.addAdapter(SingleAdapter.create(R.layout.header));
adapterGroup.addAdapter(new MyAdapter(...));
recyclerView.setAdapter(adapterGroup);
It is fairly simple and readable. You can implement more complex adapter easily using the same principle.
Excellent answer by #reaz-murshed shared here . But I dont like the part where datasize is added with +1 and returning Footer View if the end is reached.
It tells that every last element is a Footer View and I had really hard time removing the footer view.
Instead did something like this for my case -
private List<RealResponse> addEmptyLoaderResponse(List<RealResponse> originalList){
if(originalList == null){
originalList= new ArrayList<>();
}
originalList.add(new EmptyRealResponse());
return originalList;
}
private class EmptyRealResponse extends RealResponse{
/**Just an Empty class as placeholder for loader at Footer View
*
*/
}
public void setItems(List<InconcurPostResponse> items) {
this.items = addEmptyLoaderResponse(items);
}
#Override
public int getItemCount() {
return items.size();
}
#Override
public int getItemViewType(int position){
if(this.items.get(position) instanceof EmptyRealResponse){
return ViewTypes.FOOTER_VIEW_TYPE.getViewType();
}
return super.getItemViewType(position);
}
This is way cleaner for me and It loads actual Object into Recycler View. Plus I did get the benefit of removing the Footer View when I dont need it Or If I want to add more Placeholder Footer View.
I know I come late, but only recently I was able to implement such "addHeader" to the Adapter. In my FlexibleAdapter project you can call setHeader on a Sectionable item, then you call showAllHeaders. If you need only 1 header then the first item should have the header. If you delete this item, then the header is automatically linked to the next one.
Unfortunately footers are not covered (yet).
The FlexibleAdapter allows you to do much more than create headers/sections.
You really should have a look: https://github.com/davideas/FlexibleAdapter.