Develop Reference

Add ArrayLIst to Recyclerview

I have an AlertDialog in it there used to be a ListView in which the contents of the ArrayList were displayed. For beauty, I decided to replace it with Recyclerview, Card and the problems started.
Items are added to ArrayList <String> mainListWord during the work and they should be included in the Recyclerview cards. The problem is that either the entire list falls into one card at once, or each next card contains the previous elements + 1. For example: the first card: 1 element, the second card: 2 elements, etc.
How to implement it so that when a new element is added to the array, it will be placed in its own card?
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
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"
tools:context=".MainActivity">
<EditText
android:id="#+id/innerText"
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_centerInParent="true"/>
<Button
android:id="#+id/press"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="Press"
android:layout_below="#id/innerText"
android:layout_centerHorizontal="true"
android:onClick="openDialog"/>
</RelativeLayout>
recycler_item.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
app:cardCornerRadius="4dp"
android:layout_margin="4dp"
app:cardBackgroundColor="#color/colorCardBack">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="5dp"
android:background="#color/colorCard">
<ImageView
android:id="#+id/imageView_1"
android:layout_width="50dp"
android:layout_height="50dp"
android:padding="4dp" />
<TextView
android:id="#+id/textview_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Text_1"
android:textStyle="bold"
android:textColor="#android:color/black"
android:layout_centerInParent="true"
android:textSize="16sp"
android:layout_marginStart="5dp"
android:layout_toEndOf="#id/imageView_1"/>
</RelativeLayout>
</androidx.cardview.widget.CardView>
stats_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
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"
tools:context=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="50dp"
android:layout_margin="10dp"
android:background="#color/colorAccent"
android:scrollbars="vertical"
android:layout_above="#id/butClose"/>
<Button
android:id="#+id/butClose"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_centerHorizontal="true"
android:layout_alignParentBottom="true"/>
</RelativeLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
private EditText innerText;
private Button press, butClose;
private ArrayList<RecyclerViewItem> recyclerViewItem;
private ArrayList<String> mainListWord;
private AlertDialog OptionDialog;
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
#RequiresApi(api = Build.VERSION_CODES.O)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerViewItem = new ArrayList<>();
mainListWord = new ArrayList<>();
innerText = findViewById(R.id.innerText);
press = findViewById(R.id.butClose);
}
#RequiresApi(api = Build.VERSION_CODES.O)
public void makeRecyclerList(ArrayList<String> income){
String[] listWord_lenght = income.toArray(new String[0]);
String keyWord = (String.join("", listWord_lenght));
recyclerViewItem.add(new RecyclerViewItem(R.drawable.star, keyWord));
}
#RequiresApi(api = Build.VERSION_CODES.O)
public void openDialog(View v){
String word = innerText.getText().toString();
mainListWord.add(word);
makeRecyclerList(mainListWord);
Dialogus();
innerText.setText("");
}
public void Dialogus(){
LayoutInflater li = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = li.inflate(R.layout.stats_fragment, null, false);
OptionDialog = new AlertDialog.Builder(this).create();
OptionDialog.setTitle("TestInfo");
recyclerView = v.findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
adapter = new RecyclerViewAdapter(recyclerViewItem);
layoutManager = new LinearLayoutManager(this);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(layoutManager);
butClose = v.findViewById(R.id.butClose);
OptionDialog.setView(v);
OptionDialog.setCancelable(true);
butClose.setBackgroundColor(Color.CYAN);
butClose.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
OptionDialog.dismiss();
}
});
OptionDialog.show();
}
}
RecyclerViewAdapter.java
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.RecyclerViewViewHolder> {
private ArrayList<RecyclerViewItem> arrayList;
public static class RecyclerViewViewHolder extends RecyclerView.ViewHolder {
public ImageView imageView_1;
public TextView textview_1;
public RecyclerViewViewHolder(#NonNull View itemView) {
super(itemView);
imageView_1 = itemView.findViewById(R.id.imageView_1);
textview_1 = itemView.findViewById(R.id.textview_1);
}
}
public RecyclerViewAdapter(ArrayList<RecyclerViewItem> arrayList){
this.arrayList = arrayList;
}
#NonNull
#Override
public RecyclerViewViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int viewType) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.recycler_item, viewGroup, false);
RecyclerViewViewHolder recyclerViewViewHolder= new RecyclerViewViewHolder(view);
return recyclerViewViewHolder;
}
#Override
public void onBindViewHolder(#NonNull RecyclerViewViewHolder recyclerViewViewHolder, int position) {
RecyclerViewItem recyclerViewItem = arrayList.get(position);
recyclerViewViewHolder.imageView_1.setImageResource(recyclerViewItem.getImageResource());
recyclerViewViewHolder.textview_1.setText(recyclerViewItem.getText_1());
}
#Override
public int getItemCount() {
return arrayList.size();
}
}
RecyclerViewItem.java
package freijer.app.one;
public class RecyclerViewItem {
private int imageResource;
private String text_1;
public int getImageResource() {
return imageResource;
}
public void setImageResource(int imageResource) {
this.imageResource = imageResource;
}
public String getText_1() {
return text_1;
}
public void setText_1(String text_1) {
this.text_1 = text_1;
}
public RecyclerViewItem(int imageResource, String text_1) {
this.imageResource = imageResource;
this.text_1 = text_1;
}
}

CardView not showing inside fragment

I am a novice Java/Android studio student, just blindly following examples on the internet.
I wanted to make a CardView inside a fragment, but most of the examples out there were putting cardview inside an activity, so I searched and changed the appropriate codes. After some time tinkering, I managed to make it build without errors.
However, cardview is not showing up in RecyclerView.
I suspect it is a layout issue, but after all the changes with layout_height and layout_width, I can't get cardview to be seen.
Any help will be appreciated.
My code:
HomeFragment.java
public class HomeFragment extends Fragment implements View.OnClickListener {
final int ITEM_SIZE = 5;
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_home, container, false);
Button bh = v.findViewById(R.id.bh);
bh.setOnClickListener(this);
RecyclerView rv = (RecyclerView) v.findViewById(R.id.recyclerview);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
rv.setHasFixedSize(true);
rv.setLayoutManager(layoutManager);
List<Item> items = new ArrayList<>();
Item[] item = new Item[ITEM_SIZE];
item[0] = new Item(R.drawable.a, "#1");
item[1] = new Item(R.drawable.b, "#2");
item[2] = new Item(R.drawable.c, "#3");
item[3] = new Item(R.drawable.d, "#4");
item[4] = new Item(R.drawable.e, "#5");
RecyclerAdapter adaptor = new RecyclerAdapter(getActivity(), items, R.layout.fragment_home);
rv.setAdapter(adaptor);
return v;
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.bh:
((BottomNavigationView)getActivity().findViewById(R.id.nav_view)).setSelectedItemId(R.id.navigation_settings);
break;
}
}
}
RecyclerAdapter.java
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
Context context;
List<Item> items;
int item_layout;
public RecyclerAdapter(Context context, List<Item> items, int item_layout) {
this.context = context;
this.items = items;
this.item_layout = item_layout;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.fragment_home, null);
return new ViewHolder(v);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
final Item item = items.get(position);
Drawable drawable = ContextCompat.getDrawable(context, item.getImage());
holder.image.setBackground(drawable);
holder.title2.setText(item.getTitle());
holder.cardview.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(context, item.getTitle(), Toast.LENGTH_SHORT).show();
}
});
}
#Override
public int getItemCount() {
return this.items.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
ImageView image;
TextView title2;
CardView cardview;
public ViewHolder(View itemView) {
super(itemView);
image = (ImageView) itemView.findViewById(R.id.image);
title2 = (TextView) itemView.findViewById(R.id.title2);
cardview = (CardView) itemView.findViewById(R.id.cardview);
}
}
}
Item.java
public class Item {
int image;
String title;
int getImage() { return this.image; }
String getTitle() { return this.title; }
public Item(int image, String title) {
this.image = image;
this.title = title;
}
}
fragment_home.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
android:id="#+id/MainLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_home"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/title_home"
android:textSize="40sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.952"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerview"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toTopOf="#+id/bh"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/text_home" />
<Button
android:id="#+id/bh"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="50dp"
android:text="#string/title_settings"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
card.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.google.android.material.card.MaterialCardView
android:id="#+id/cardview"
android:layout_width="match_parent"
android:layout_height="200dp"
android:clickable="true"
android:focusable="true"
android:foreground="?android:attr/selectableItemBackground"
app:cardCornerRadius="20dp"
app:cardElevation="4dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:id="#+id/image"
android:layout_width="match_parent"
android:layout_height="150dp"
android:scaleType="centerCrop" />
<TextView
android:id="#+id/title2"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_margin="5dp"
android:text="TextView"
android:textSize="25sp" />
</LinearLayout>
</com.google.android.material.card.MaterialCardView>

Seems you are inflating the wrong layout in RecyclerAdapter.java
try this
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
Context context;
List<Item> items;
int item_layout;
public RecyclerAdapter(Context context, List<Item> items, int item_layout) {
this.context = context;
this.items = items;
this.item_layout = item_layout;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.card, null);
return new ViewHolder(v);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
final Item item = items.get(position);
Drawable drawable = ContextCompat.getDrawable(context, item.getImage());
holder.image.setBackground(drawable);
holder.title2.setText(item.getTitle());
holder.cardview.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(context, item.getTitle(), Toast.LENGTH_SHORT).show();
}
});
}
#Override
public int getItemCount() {
return this.items.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
ImageView image;
TextView title2;
CardView cardview;
public ViewHolder(View itemView) {
super(itemView);
image = (ImageView) itemView.findViewById(R.id.image);
title2 = (TextView) itemView.findViewById(R.id.title2);
cardview = (CardView) itemView.findViewById(R.id.cardview);
}
}

Item alignments are not proper in horizontal recycler view using grid layout manager

The view inside recycler view is not aligned properly. The items inside recyclerview are having different height on adding new item.
I tried of using display metrics but could not achieve it. My item list can be changed by adding or deleting items but the view padding, width and height must h=not get disturbed.
categoryRecyclerView = findViewById(R.id.categoriesRecyclerView);
GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 1,GridLayoutManager.HORIZONTAL, false);
categoryRecyclerView.setLayoutManager(gridLayoutManager);
categoryRecyclerView.addItemDecoration(new ItemDecorator(getResources().getDimensionPixelSize(R.dimen.item_spacing), 3));
CategoryItemAdapter categoryItemAdapter = new CategoryItemAdapter(this, categoryList);
categoryRecyclerView.setAdapter(categoryItemAdapter);
Code for Adapter
public class CategoryItemAdapter extends RecyclerView.Adapter<CategoryItemAdapter.MyViewHolder> {
private Context context;
private List<Category> categoryList;
private onItemClickListener mItemClickListener;
public CategoryItemAdapter(Context context, List<Category> categoryList) {
this.context = context;
this.categoryList = categoryList;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.category_item, parent, false);
return new MyViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull CategoryItemAdapter.MyViewHolder holder, int position) {
Category category = (Category) categoryList.get(position);
holder.textView.setText(category.getCategoryName());
}
#Override
public int getItemCount() {
return categoryList.size();
}
public void setOnItemClickListener(onItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
}
public interface onItemClickListener {
void onItemClickListener(View view, int position, Category category);
}
class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
CardView cardview;
TextView textView;
ImageView selectItem;
RelativeLayout selectItemLayout;
LinearLayout linearLayout;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
cardview = itemView.findViewById(R.id.cardview);
textView = itemView.findViewById(R.id.categoryName);
linearLayout = itemView.findViewById(R.id.llbackground);
selectItemLayout = itemView.findViewById(R.id.selectItemLayout);
selectItem = itemView.findViewById(R.id.selectItem);
selectItemLayout.setVisibility(authenticationHelper.isAdmin() ? View.VISIBLE : View.GONE);
itemView.setOnClickListener(this);
Util.setRandomGradientColor(linearLayout, GradientDrawable.Orientation.LEFT_RIGHT);
}
#Override
public void onClick(View view) {
if (mItemClickListener != null) {
mItemClickListener.onItemClickListener(view, getAdapterPosition(), categoryList.get(getAdapterPosition()));
}
}
}
}
Code for view
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_height="wrap_content"
android:layout_width="wrap_content">
<androidx.cardview.widget.CardView
android:id="#+id/cardview"
android:layout_width="150dp"
android:layout_height="100dp"
card_view:cardCornerRadius="5dp"
card_view:cardElevation="2dp">
<LinearLayout
android:id="#+id/llbackground"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#drawable/category_gradient"
android:gravity="center">
<TextView
android:id="#+id/categoryName"
android:text="Men"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:textColor="#color/colorWhite"
android:textStyle="bold"/>
</LinearLayout>
<RelativeLayout
android:id="#+id/selectItemLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:elevation="10dp"
android:padding="5dp">
<ImageView
android:id="#+id/selectItem"
android:layout_width="20dp"
android:layout_height="20dp"
android:clickable="false"
android:tag="#string/unchecked"
android:enabled="false"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:src="#drawable/circle"/>
</RelativeLayout>
</androidx.cardview.widget.CardView>
</RelativeLayout>
Recycler view in activity
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/categoriesRecyclerView"
android:layout_below="#+id/categoriesLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"/>
Thanks for help!!

ListView CustomAdapter not showing first position results

I'm new to Android Studio and coding in general and I am trying to display a custom ListView with an image of a colour and the name of the colour. I have used a custom Adapter to inflate the view with two arrays containing the drawable image colours and string of the names.
The problem I am having - the custom adapter is only displaying the layers from position 1 and onwards. For example, where the first layer should be img_01 and "red" - it is displaying img_02 and "Orange".
I've tried debugging the code and it seems that though the adapter is setting the values for position 0, but I cannot find the reason why it is not displaying (as the others are displaying fine).
The images & names are just placeholders, so an alternative solution that doesn't include both the drawables and names wouldn't be viable,
Thank you in advance
CustomAdapter.java
public class CustomAdapter extends BaseAdapter {
Context context;
int[] images;
String[] colour;
LayoutInflater mInflater;
public CustomAdapter(Context c, int[] i, String[] col) {
this.context = c; //sets the application context that has been passed to the adapter
this.images = i; //sets the images array that has been passed to the adapter
this.colour = col; //sets the colour array that has been passed to the adapter
mInflater = (LayoutInflater.from(context)); //sets the layout inflater from context
}
#Override
public int getCount() { //total number of elements in the array
return images.length;
}
#Override
public Object getItem(int position) { //gets the item using the position
return null;
}
#Override
public long getItemId(int position) { //gets the item position
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) { //this is used to update the view
convertView = mInflater.inflate(R.layout.custom_layout, null);
ImageView image = convertView.findViewById(R.id.imageView);
TextView text = convertView.findViewById(R.id.textView);
text.setText(colour[position]);
image.setImageResource(images[position]);
return convertView;
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
ListView mListView;
int[] images = {R.drawable.img01,
R.drawable.img02,
R.drawable.img03,
R.drawable.img04};
String[] colour = {"Red",
"Orange",
"Yellow",
"Green"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView = findViewById(R.id.listView);
CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), images, colour);
//passes information of images and application context to the item adapter
mListView.setAdapter(customAdapter);
//sets the adapter to the listview
}
}
custom_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent" android:layout_height="match_parent">
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginStart="7dp"
android:layout_marginLeft="7dp"
android:layout_marginTop="9dp"
app:srcCompat="#drawable/img01" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginStart="99dp"
android:layout_marginLeft="99dp"
android:layout_marginTop="36dp"
android:text="colourName" />
</RelativeLayout>
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ListView
android:id="#+id/listView"
android:layout_width="409dp"
android:layout_height="729dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Try to set the height of the ListView to wrap_content instead of hardcoding it
<ListView
...
android:layout_height="wrap_content"/>

You can do it with RecyclerView.
Create a custom class
public class ExampleItem {
private int mImageResource; //your color image
private String mText1; //your text
public ExampleItem(int imageResource, String text1) {
mImageResource = imageResource;
mText1 = text1;
}
public int getImageResource() {
return mImageResource;
}
public String getText1() {
return mText1;
}
}
Create a XML layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="4dp"
app:cardCornerRadius="4dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="4dp">
<ImageView
android:id="#+id/imageView"
android:layout_width="50dp"
android:layout_height="50dp"
android:padding="2dp" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toEndOf="#+id/imageView"
android:text="Line 1"
android:textColor="#android:color/black"
android:textSize="20sp"
android:textStyle="bold" />
</RelativeLayout>
</android.support.v7.widget.CardView>
Create a Recycler View Adapter
public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {
private ArrayList<ExampleItem> mExampleList;
public static class ExampleViewHolder extends RecyclerView.ViewHolder {
public ImageView mImageView;
public TextView mTextView1;
public ExampleViewHolder(View itemView) {
super(itemView);
mImageView = itemView.findViewById(R.id.imageView);
mTextView1 = itemView.findViewById(R.id.textView);
}
}
public ExampleAdapter(ArrayList<ExampleItem> exampleList) {
mExampleList = exampleList;
}
#Override
public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.example_item, parent, false);
ExampleViewHolder evh = new ExampleViewHolder(v);
return evh;
}
#Override
public void onBindViewHolder(ExampleViewHolder holder, int position) {
ExampleItem currentItem = mExampleList.get(position);
holder.mImageView.setImageResource(currentItem.getImageResource());
holder.mTextView1.setText(currentItem.getText1());
}
#Override
public int getItemCount() {
return mExampleList.size();
}
}
your activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.application.recyclerviewproject.MainActivity">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/darker_gray"
android:padding="4dp"
android:scrollbars="vertical" />
</RelativeLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<ExampleItem> exampleList = new ArrayList<>();
exampleList.add(new ExampleItem(R.drawable.img01, "Red"));
exampleList.add(new ExampleItem(R.drawable.img02, "Orange"));
exampleList.add(new ExampleItem(R.drawable.img03, "Yellow"));
exampleList.add(new ExampleItem(R.drawable.img04, "Green"));
mRecyclerView = findViewById(R.id.recyclerView);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
mAdapter = new ExampleAdapter(exampleList);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setAdapter(mAdapter);
}
}

"E/RecyclerView: No adapter attached; skipping layout"

So, for a personal project I'm making a stream app for Android which are separated by three fragments in the main screen where each of those fragment will be a list of a type of show in our archive, like movies, TV series and animations by using a RecyclerView inside of them.
That being said, after some errors that I managed to fix, the app is not showing what was expected, by skipping the RecyclerView because it has no "adapter".
Here is the code so far:
The main activity:
public class MenuPrincipal extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu_principal);
AbasMenuPrincipalAdapter adapter = new AbasMenuPrincipalAdapter( getSupportFragmentManager() );
adapter.adicionar( new FilmesFragment() , "Filmes");
adapter.adicionar( new SeriesFragment() , "Series");
adapter.adicionar( new AnimacoesFragment() , "Animações");
ViewPager viewPager = (ViewPager) findViewById(R.id.abas_view_pager);
viewPager.setAdapter(adapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.abas);
tabLayout.setupWithViewPager(viewPager);
}
}
One of the fragments used on the main screen:
public class AnimacoesFragment extends Fragment {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
ArrayList<Item> exemploItemList = new ArrayList<Item>();
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.animacoes_fragment, container, false);
TextView tv = view.findViewById(R.id.text1);
tv.setText("Você está na terceira aba");
exemploItemList.add(new Item(R.drawable.ic_android, "Line1", "line2"));
exemploItemList.add(new Item(R.drawable.ic_desktop_mac, "Line2", "line3"));
exemploItemList.add(new Item(R.drawable.ic_laptop_windows, "Line4", "line5"));
mRecyclerView = (RecyclerView) view.findViewById(R.id.AnimacaoRecyclerView);
mRecyclerView.setHasFixedSize(true);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
mRecyclerView.setLayoutManager(llm);
ItemAdapter adapter = new ItemAdapter(exemploItemList);
mAdapter = adapter;
mRecyclerView.setAdapter(mAdapter);
return view;
}
}
And its layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<TextView
android:id="#+id/text1"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/AnimacaoRecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="4dp"
android:scrollbars="vertical" />
</LinearLayout>
This is what I'm trying to show on that RecyclerView (later will be the real thing, now it's just a test):
public class Item {
private int mImageResource;
private String text1;
private String text2;
public Item(int mImageResource, String text1, String text2) {
this.mImageResource = mImageResource;
this.text1 = text1;
this.text2 = text2;
}
public int getmImageResource() {
return mImageResource;
}
public void setmImageResource(int mImageResource) {
this.mImageResource = mImageResource;
}
public String getText1() {
return text1;
}
public void setText1(String text1) {
this.text1 = text1;
}
public String getText2() {
return text2;
}
public void setText2(String text2) {
this.text2 = text2;
}
}
It's layout:
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
app:cardCornerRadius="4dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="4dp">
<ImageView
android:id="#+id/imageView"
android:layout_width="50dp"
android:layout_height="50dp"
android:contentDescription="#string/imagem"
android:padding="2dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginStart="50dp"
android:layout_marginTop="0dp"
android:text="#string/line1"
android:textColor="#000000"
android:textSize="20sp"
android:textStyle="bold"
android:id="#+id/textView"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginStart="50dp"
android:layout_marginTop="28dp"
android:text="#string/line2"
android:textSize="15sp"
android:textStyle="bold"
android:id="#+id/textView2"/>
</RelativeLayout>
</androidx.cardview.widget.CardView>
Finally, the adapter used to convert the list:
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ItemViewHolder> {
private ArrayList<Item> mItemList;
public static class ItemViewHolder extends RecyclerView.ViewHolder{
public ImageView mImageView;
public TextView mTextView1;
public TextView mTextView2;
public ItemViewHolder(#NonNull View itemView) {
super(itemView);
mImageView = itemView.findViewById(R.id.imageView);
mTextView1 = itemView.findViewById(R.id.textView);
mTextView2 = itemView.findViewById(R.id.textView2);
}
}
#NonNull
#Override
public ItemViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);
ItemViewHolder ivh = new ItemViewHolder(v);
return ivh;
}
public ItemAdapter(ArrayList<Item> itemList){
mItemList = itemList;
}
#Override
public void onBindViewHolder(#NonNull ItemViewHolder holder, int position) {
Item currentItem = mItemList.get(position);
holder.mImageView.setImageResource(currentItem.getmImageResource());
holder.mTextView1.setText(currentItem.getText1());
holder.mTextView2.setText(currentItem.getText2());
}
#Override
public int getItemCount() {
return mItemList.size();
}
}

First of all, check your fragment layout file. The linear layout parent orientation set to 'horizontal' and width of it's child views ('textview' & 'recyclerview') is match parent. This won't work.
Try to initialize your recyclerview adapter in 'onCreate' and use 'notifyDataSetChanged()' after setting up the adapter with recyclerview.