Develop Reference

Expandable recycler view and a textview below issue

I'm trying to implement a 2 expandable recyclerview with 2 headings.So my view has
1.
2.
3.
4.
Since my recyclerview is expandable, and when I expand the 1st recyclerview , it goes inside my 2nd textview.
ie.there is a separate scroll for my recycler view.
I want the 2nd textview and recyclerview to move down when expanding the 1st recyclerview.
activity.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_marginBottom="10dp"
tools:context=".ListActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold"
android:textSize="22sp"
android:text="Weightage: 40%"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.RecyclerView
android:id="#+id/recview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#fafafa" />
</LinearLayout>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold"
android:textSize="22sp"
android:layout_marginBottom="10dp"
android:text="Weightage: 60%"/>
<android.support.v7.widget.RecyclerView
android:id="#+id/recview2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#fafafa" />
</LinearLayout>
</ScrollView>
the same happens with the second recyclerview. On expanding the second recycler view, recyclerview items have a separate scroll and the text above stays at a place.The overall scroll doesn't work.

You can achieve this using only one Recyclerview. Make one model class named "Model" of your data, in which add one variable like "isHeader". When you prepare your data list to show in Recyclerview make 2 model object with
'isHeader = true'
Also, make two (item_layout.xml & header_layout.xml) xml files, one for header & another for your original data item.
And in Recyclerview adapter class you have two separate ViewHolder classes for each of the above layouts. refer this for more details and example
public class MultiViewTypeAdapter extends RecyclerView.Adapter {
public static final int HEADER_VIEW = 0;
public static final int LIST_VIEW = 1;
private Resources resources;
private DownloadListener downloadListener;
public MyToursAdapter(List<Model> objects) {
super(objects);
resources = App.getApp().getResources();
}
#NonNull
#Override
public RecycleView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
if (viewType == HEADER_VIEW) {
return new SectionHeaderItemViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.header_layout, parent, false));
} else
return new ListItemViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false));
}
#Override
public void onBindViewHolder(#NonNull BaseRecycleAdapter.ViewHolder holder, int position) {
if (getItemViewType(position) == HEADER_VIEW)
((HeaderItemViewHolder) holder).bindHeaderViewHolder(objects.get(position));
else
((ListItemViewHolder) holder).bindListViewHolder(objects.get(position));
}
#Override
public int getItemViewType(int position) {
if (objects.get(position).isHeader())
return HEADER_VIEW;
else
return LIST_VIEW;
}
public class ListItemViewHolder extends BaseRecycleAdapter.ViewHolder {
//write code to show data from list object.
}
public class HeaderItemViewHolder extends BaseRecycleAdapter.ViewHolder {
//write code to show data from list object.
}
}
enter code here

How do I not recycle only the first 2 views of my recyclerview or any items?

I am using a recyclerview for displaying and broadcasting videos of users. However, when I scroll through the recycler view, I see my first view, which has my video gets recycled hence why it's not visible to other users. Is there a way I can make sure that the first view is not recycled so I dont have to worry about my video view getting resetrecycled every single time I scroll through my list?
Here's my code :
In my fragment...
...
<android.support.v7.widget.RecyclerView
android:id="#+id/videoList"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="invisible"
app:layout_constraintBottom_toTopOf="#+id/myButtonContainer"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/myoldContainer">
...
and the corresponding adapter...
public class GroupAdapter extends RecyclerView.Adapter<GroupAdapter.myViewHolder> {
private CopyOnWriteArrayList<Person> persons;
private Context mContext;
public GroupAdapter(#NonNull final CopyOnWriteArrayList<Person> persons , Context context) {
this.persons = persons;
this.mContext= context;
for (Person person : this.persons) {
//get names
}
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
final View layout = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_person, parent, false);
final MyViewHolder viewHolder = new MyViewHolder(layout);
return viewHolder;
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
final Person person = person.get(position);
final Participant participant = person.getParticipant();
if (person.getName() != null) {
holder.personName.setText(person.getName());
}
if (person.getImage() != null) {
holder.personImage.setImageBitmap(person.getImage());
} else {
holder.personImage.setImageResource(R.drawable.default_profile);
}
holder.personImage.setVisibility(View.INVISIBLE);
holder.personImage.setVisibility(View.VISIBLE);
final VideoView videoView;
if (participant.isMe) {
videoView = participant.videoStreamer.videoView;
} else {
videoView = participant.videoPlayer.videoView;
}
if (holder.personVideo.getChildCount() != 0) {
holder.personVideo.removeAllViews();
}
if (videoView.getParent() != null) {
ViewGroup parent = (ViewGroup) videoView.getParent();
parent.removeView(videoView);
}
holder.personVideo.addView(videoView, myViewHolder.videoLayoutParams);
if (person.isVideoPaused()) {
holder.personVideo.setVisibility(View.INVISIBLE);
holder.personImage.setVisibility(View.VISIBLE);
} else {
holder.personVideo.setVisibility(View.VISIBLE);
holder.personImage.setVisibility(View.INVISIBLE);
}
}
#Override
public int getItemCount() {
return persons.size();
}
public static final class MyViewHolder extends RecyclerView.ViewHolder {
#BindView(R.id.personVideo)
public ViewGroup personVideo;
#BindView(R.id.personImage)
public ImageView personImage;
#BindView(R.id.personName)
public TextView personName;
protected static FrameLayout.LayoutParams videoLayoutParams = new FrameLayout.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT
);
public MyViewHolder(View itemView) {
super(itemView);
ButterKnife.bind(this, itemView);
}
}
}
Here's how I am setting it in my fragment:
LinearLayoutManager manager = new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL, false);
videoAdapter = new VideoAdapter(myHelper.getPeople(), getContext());
videoList.setLayoutManager(manager);
videoList.setAdapter(videoAdapter);
item_person:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_marginTop="0dp"
android:background="#drawable/person_border"
xmlns:app="http://schemas.android.com/apk/res-auto">
<RelativeLayout
android:id="#+id/personContainer"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent">
<FrameLayout
android:id="#+id/personVideo"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/black" />
<ImageView
android:id="#+id/personImage"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/black"
android:src="#drawable/default_profile" />
<TextView
android:id="#+id/personName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#AA555555"
android:gravity="center_horizontal|bottom"
android:textColor="#color/green"
android:textSize="12sp"
android:lines="1"
android:ellipsize="end"
tools:text="androiduser#gmail.com"
android:layout_alignParentBottom="true" />
</RelativeLayout>
</android.support.constraint.ConstraintLayout>
fragment with recycle view: xml
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<RelativeLayout>
....
</RelativeLayout>
<include containers>...</include>
...
<android.support.v7.widget.RecyclerView
android:id="#+id/personList"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="invisible"
>
</android.support.v7.widget.RecyclerView>
</android.support.constraint.ConstraintLayout>

I don't think that "not recycling" the video view will actually stop it from being destroyed when you scroll. It's not the recycling is the problem but the view unbinding.
I think such complex component such as VideoView should not be inside the RecyclerView at all.. You can try adding it as a static content on top, which most likely will solve the issue. You can use a NestedScrollView for that. Take a look here: Recyclerview inside scrollview- How to scroll whole content?
If you still think you want to keep it in the RecyclerView and disable the recycling, do the following.
Create a separate view type for your video view items. Here is an example:
https://stackoverflow.com/a/26573338/3086818. Treat your video view item as a header view from the example.
Once you do this, there is a RecycledViewPool class which manages the recycling of items inside a RecyclerView. You can tell it which views to recycle and which not. By default it recycles all views. To disable recycling for your video view items use your new view type like this:
recyclerView.getRecycledViewPool().setMaxRecycledViews(TYPE_VIDEO_VIEW, 0);
where TYPE_VIDEO_VIEW is the new type that you created using the previous example. The number 0 tells the RecyclerView how many items to recycle - in this case it's 0, meaning "do not recycle". More info about this here: https://stackoverflow.com/a/36313437/3086818.
I hope this helps.. Good luck!

The answer is yes, you can actually do that.
Since you said "The first item" so you simply add a check.
if(position == 0)
{
holder.setIsRecyclable(false); //This line prevents the row from recycling
}

RecyclerView - Layout_weight is ignored when it loads first time

I have an Activity that contains a Fragment. Fragment contains a RecyclerView, displaying CardViews.
CardView is very simple, just a TextView and a CustomView. This is the layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="100dp">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="100dp"
android:id="#+id/card_current_heat_cardview"
android:layout_gravity="center_vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="5dp"
android:layout_marginBottom="5dp"
android:weightSum="4">
<TextView
android:id="#+id/card_current_heat_textview"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:textStyle="bold"
android:textColor="#000000"
android:background="#android:color/holo_red_dark"
android:gravity="center_vertical"/>
<com.amige.vm2.CurrentHeatChartView
android:id="#+id/card_current_heat_chart_view"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="3"/>
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
TextView should use 1/4 of the width, and the CustomView 3/4.
Im having trouble understanding why weights are ignored the first time the RecyclerView loads
Image of RecyclerView loaded for the first time
But if I scroll up and down, the layout works as expected for some Cards
Image of RecyclerView scrolled up and down
I also have another Activity (no fragment involved here) that has a RecyclerView and IS using this same CardView Layout and it works perfectly!!
I dont know if it has to do with the Fragment...
What am I missing?
Thanks!
EDIT
This the Adapter code
public class MainAdapter extends RecyclerView.Adapter<MyFragment.MainAdapter.ViewHolder>
{
public MainAdapter()
{
}
#Override
public MyFragment.MainAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_current_heat, parent, false);
return new MyFragment.MainAdapter.ViewHolder(v);
}
#Override
public void onBindViewHolder(MyFragment.MainAdapter.ViewHolder holder, int position)
{
if (arrayList.size() == 2)
{
if (position == 0)
{
holder.variableNameTextView.setText(“Var Name”);
holder.currentHeatChartView.reloadChartWithSamples(arrayList.get(0));
}
else
{
if ((position - 1) < arrayList.get(1).size())
{
HashMap variableHashMap = (HashMap) arrayList.get(1).get(position - 1);
holder.variableNameTextView.setText(variableHashMap.get("VarName") != null ? (String)variableHashMap.get("VarName") : "");
holder.currentHeatChartView.reloadChartWithVariableValuesAndColors(variableHashMap, colorGradientsArrayList.get((position - 1) % colorGradientsArrayList.size()));
}
}
}
}
#Override
public int getItemCount()
{
if (arrayList.size() == 2)
{
if (arrayList.get(1).size() > 0)
{
return 1 + arrayList.get(1).size();
}
else
{
return 1;
}
}
return 0;
}
public class ViewHolder extends RecyclerView.ViewHolder
{
TextView variableNameTextView;
CurrentHeatChartView currentHeatChartView;
public ViewHolder(View v)
{
super(v);
this.variableNameTextView = (TextView) v.findViewById(R.id.card_current_heat_textview);
this.currentHeatChartView = (CurrentHeatChartView) v.findViewById(R.id.card_current_heat_chart_view);
}
}
}

I found the culprit.
There was a ConstraintLayout on top of the hierarchy of the Activity containing the Fragment. Since I was working with nested layouts, ConstraintLayout was not the right way to go.
I changed it to RelativeLayout and the cards are now rendered properly.

I think your layout inflation is wrong.
View view = View.inflate(mContext, R.layout.your_layout, null);
If you do like that change your code like this.
View view = LayoutInflater.from(mContext).(R.layout.your_layout, parent, false);
Hope it helps:)

RecyclerView with expandable Views

I have already found this post that contains an answer how to do it. But there are some things that don't work and I can't figure out why.
#Override
public void onBindViewHolder(final ShipViewer.anAdapter.NumberViewHolder holder, final int position) {
final int[] mExpandedPosition = {-1};
final boolean isExpanded = position== mExpandedPosition[0];
holder.details.setVisibility(isExpanded?View.VISIBLE:View.GONE);
holder.itemView.setActivated(isExpanded);
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mExpandedPosition[0] = isExpanded ? -1:position;
TransitionManager.beginDelayedTransition(recyclerView);
notifyDataSetChanged();
}
});
holder.bind(position);
}
First of, I can't resolve details. Details is a gone ConstraintLayout inside of my Viewholder:
<android.support.constraint.ConstraintLayout
android:id="#+id/details"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginTop="0dp"
android:visibility="gone"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/bigtextname">
<TextView
android:id="#+id/textView10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView" />
</android.support.constraint.ConstraintLayout>
My second problem is that I can't resolve recyclerView. I have already tried inserting my adapter but that also doesn't work.
Lastly, is it fine that so many things are final here? This doesn't seem right, but if I don't do it it tells me that they need to be final to be accessed from an inner class.
My recyclerView:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/ShipRec"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/black">
</android.support.v7.widget.RecyclerView>
Initialization of RecyclerView:
View b = inflater.inflate(R.layout.shipviewerrecview, container, false);
if(!shipsCursor.moveToPosition(0)) {return b;}
shipropView = (RecyclerView) b.findViewById(R.id.ShipRec);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
shipropView.setLayoutManager(layoutManager);
shipropView.setHasFixedSize(true);
shippropAdapter = new ShipViewer.anAdapter(numberofField, Names, Type, Size, MaxSize, Amount);
ShipsDbHelper.close();
return b;

Probably expandable-recycler-view library from bignerdranch will useful for you.

How to reduce space between columns in recycler view(GridLayoutManager) in android

I am using GridLayoutManager of recyclerview to display custom gallery in my app. I have implementated all the features like gallery. But there is a small thing Im stuck with. In one row I have 3 images. But I need to reduce the space between the images. While doing so , I dont want to show more than 3 images in a row, but the image size (if needed) can increase.

You can use custom RecyclerViewItemDecorator:
public class RecyclerViewItemDecorator extends RecyclerView.ItemDecoration {
private int spaceInPixels;
public RecyclerViewItemDecorator(int spaceInPixels) {
this.spaceInPixels = spaceInPixels;
}
#Override
public void getItemOffsets(Rect outRect, View view,
RecyclerView parent, RecyclerView.State state) {
outRect.left = spaceInPixels;
outRect.right = spaceInPixels;
outRect.bottom = spaceInPixels;
if (parent.getChildLayoutPosition(view) == 0) {
outRect.top = spaceInPixels;
} else {
outRect.top = 0;
}
}
}
Then add it to your RecyclerView:
// For example 10 pixels
int spaceInPixels = 10;
mRecyclerView.addItemDecoration(new RecyclerViewItemDecorator(spaceInPixels));
Hope it helps!

Use this for the recycler view,
this.mRecyclerView.setLayoutManager(new GridLayoutManager(getContext(), 3));
this.mRecyclerView.addItemDecoration(new HorizontalDividerItemDecoration.Builder(getContext())
.color(Color.DKGRAY)
.build());
this.mRecyclerView.addItemDecoration(new VerticalDividerItemDecoration.Builder(getContext())
.color(Color.DKGRAY)
.build());
and in your layout file for each item, set the Image in such a way to meet the edges of the container.
eg:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/RlayoutGrid"
android:layout_width="220dp"
android:layout_height="170dp"
android:background="#android:color/black">
<ImageView
android:id="#+id/prefence_imageButton"
android:layout_width="match_parent"
android:layout_height="170dp"
android:background="#android:color/black"
android:focusable="false"
android:focusableInTouchMode="false"
android:scaleType="fitXY"
/>
</RelativeLayout>
and add this to your build.gradle
compile 'com.yqritc:recyclerview-flexibledivider:1.2.4'

To remove spacing you can use outRect.setEmpty()
RecyclerView.ItemDecoration divider = new RecyclerView.ItemDecoration(){
#Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
outRect.setEmpty();
}
};
grid.addItemDecoration(divider);