RecyclerView in Android using Java and Xml

1. In this document I am writing the steps I take to implement a RecyclerView in android. Please go through the document and I am sure it will be helpful. Please share your valuable feedbacks I would really appreciate it. To check out RecyclerView using Kotlin in Android check this article (https://medium.com/@aayushpuranik/recycler-view-using-kotlin-and-xml-afc8dc465bf9)
2. For creating a recycler view basically we need 3 things :

• Data (a list of items),
• View (RecyclerView and layout to display row data),
• Adapter(extends RecyclerView.Adapter).

3. For creating a RecyclerView we will use :

• RecyclerView(.xml in activity or fragment)
• A layout file for cell
• Model class
• Adapter class

4. Let us start with simple instructions.

1. We need to add dependency for recycler view in build.gradle(Module:App) : implementation ‘com.android.support:recyclerview-v7:27.1.1’

Take a recycler view in your activity or fragment, in this example I am taking RecyclerView in: activity_main.xml

<android.support.v7.widget.RecyclerView android:id=”@+id/ContactsRecyclerView” android:layout_width=”match_parent” android:layout_height=”match_parent”/>

3. Now we need to create a cell for displaying data in each row. For that we will create a new .xml file

template_contact.xml
<?xml version=”1.0" encoding=”utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:app=”http://schemas.android.com/apk/res-auto" xmlns:tools=”http://schemas.android.com/tools" android:layout_height=”wrap_content” android:layout_width=”match_parent”
android:layout_gravity=”top” android:background=”@drawable/rectangle_shape” xmlns:android=”http://schemas.android.com/apk/res/android">
<android.support.constraint.ConstraintLayout android:id=”@+id/contact_layout” android:layout_width=”match_parent” android:layout_height=”0dp” android:layout_gravity=”top” android:layout_marginTop=”2dp” android:background=”@drawable/rectangle_shape” app:layout_constraintEnd_toEndOf=”parent” app:layout_constraintStart_toStartOf=”parent” app:layout_constraintTop_toTopOf=”parent”>
<ImageView android:id=”@+id/Contact_Avatar” android:layout_width=”wrap_content” android:layout_height=”41dp” android:layout_marginBottom=”8dp” android:layout_marginEnd=”8dp” android:layout_marginStart=”16dp” android:tint=”@color/colorText” app:layout_constraintBottom_toTopOf=”@+id/guideline2" app:layout_constraintEnd_toStartOf=”@+id/guideline3" app:layout_constraintHorizontal_bias=”0.0" app:layout_constraintStart_toStartOf=”parent” app:layout_constraintTop_toTopOf=”parent” app:layout_constraintVertical_bias=”0.51" app:srcCompat=”@drawable/ic_face_black_24dp” />
<TextView android:id=”@+id/Contact_Name” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_marginBottom=”8dp” android:layout_marginEnd=”8dp” android:layout_marginStart=”8dp” android:fontFamily=”@font/roboto_bold” android:text=”TextView” android:textColor=”@color/colorText” android:textSize=”14sp” app:layout_constraintBottom_toTopOf=”@+id/guideline2" app:layout_constraintEnd_toStartOf=”@+id/guideline3" app:layout_constraintHorizontal_bias=”0.0" app:layout_constraintStart_toEndOf=”@+id/Contact_Avatar” app:layout_constraintTop_toTopOf=”parent” app:layout_constraintVertical_bias=”0.32999998" />
<TextView android:id=”@+id/Contact_Designation” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_marginBottom=”8dp” android:layout_marginEnd=”8dp” android:layout_marginStart=”8dp” android:layout_marginTop=”4dp” android:fontFamily=”@font/roboto_light” android:text=”TextView” android:textColor=”@color/colorSubText” android:textSize=”12sp” app:layout_constraintBottom_toTopOf=”@+id/guideline2" app:layout_constraintEnd_toStartOf=”@+id/guideline3" app:layout_constraintHorizontal_bias=”0.0" app:layout_constraintStart_toEndOf=”@+id/Contact_Avatar” app:layout_constraintTop_toBottomOf=”@+id/Contact_Name” app:layout_constraintVertical_bias=”0.0" />
<TextView android:id=”@+id/textView8" android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_marginBottom=”8dp” android:layout_marginEnd=”8dp” android:layout_marginStart=”4dp” android:layout_marginTop=”4dp” android:gravity=”center_horizontal” android:text=”|” android:textColor=”@color/colorSubText” app:layout_constraintBottom_toTopOf=”@+id/guideline2" app:layout_constraintEnd_toEndOf=”parent” app:layout_constraintHorizontal_bias=”0.0" app:layout_constraintStart_toEndOf=”@+id/Contact_Designation” app:layout_constraintTop_toBottomOf=”@+id/Contact_Name” app:layout_constraintVertical_bias=”0.0" />
<TextView android:id=”@+id/Contact_Country” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_marginBottom=”8dp” android:layout_marginEnd=”8dp” android:layout_marginStart=”4dp” android:layout_marginTop=”4dp” android:fontFamily=”@font/roboto_light” android:text=”TextView” android:textColor=”@color/colorSubText” android:textSize=”12sp” app:layout_constraintBottom_toTopOf=”@+id/guideline2" app:layout_constraintEnd_toStartOf=”@+id/guideline3" app:layout_constraintHorizontal_bias=”0.0" app:layout_constraintStart_toEndOf=”@+id/textView8" app:layout_constraintTop_toBottomOf=”@+id/Contact_Name” app:layout_constraintVertical_bias=”0.0" />
<android.support.constraint.Guideline android:id=”@+id/guideline2" android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:orientation=”horizontal” app:layout_constraintGuide_begin=”80dp” />
<android.support.constraint.Guideline android:id=”@+id/guideline3" android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:orientation=”vertical” app:layout_constraintGuide_begin=”224dp” />
</android.support.constraint.ConstraintLayout> </android.support.constraint.ConstraintLayout>

4. Above steps help us to create view or the UI component, now we will create a model class representing Contact to show the data

Contact.java
public class ContactsModel {
int Contact_avatar;
String Contact_Name,Contact_Designation,Contact_Country,Contact_Phone,Contact_Email;
public ContactsModel(){}
public void setContact_avatar(int contact_avatar) {Contact_avatar = contact_avatar;}
public int getContact_avatar() {return Contact_avatar;}
public void setContact_Name(String contact_Name) {Contact_Name = contact_Name;}
public String getContact_Name() {return Contact_Name;}
public void setContact_Designation(String contact_Designation) {Contact_Designation = contact_Designation;}
public String getContact_Designation() {return Contact_Designation;}
public void setContact_Country(String contact_Country) {Contact_Country = contact_Country;}
public String getContact_Country() {return Contact_Country;}
public void setContact_Phone(String contact_Phone) {Contact_Phone =contact_Phone;}
public String getContact_Phone() {return Contact_Phone;}
public void setContact_Email(String contact_Email) { Contact_Email = contact_Email; }
public String getContact_Email() { return Contact_Email; }}

5. An Adapter is the bridge between data source and UI components, with the help of adapter we are able to display data into each cell.

ContactsAdapter
public class ContactsAdapter extends RecyclerView.Adapter<ContactsAdapter.ContactViewHolder> {
Context Context;
List <ContactsModel> Contacts;
OnElementClickListener ELementClickListener;
public ContactsAdapter(Context context, List <ContactsModel> contacts, OnElementClickListener onElementClickListener) 
{
this.Context = context;
this.Contacts = contacts;
this.ELementClickListener = onElementClickListener;
}
@Override
public ContactViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
ContactViewHolder contactViewHolder = null;
View contactView = LayoutInflater.from(this.Context).inflate(R.layout.template_contacts,parent,false);
contactViewHolder = new ContactViewHolder(contactView);
return contactViewHolder;
}
@Override
public void onBindViewHolder(ContactViewHolder holder, final int position) {
final ContactViewHolder contactViewHolder = (ContactViewHolder)holder;
ContactsModel contact = Contacts.get(position);
contactViewHolder.contact_avatar.setImageResource(contact.getContact_avatar());
contactViewHolder.Contact_Name.setText(contact.getContact_Name());
contactViewHolder.Contact_Designation.setText(contact.getContact_Designation());
contactViewHolder.Contact_Country.setText(contact.getContact_Country());
}
@Override
public int getItemCount() {return Contacts.size();}
class ContactViewHolder extends RecyclerView.ViewHolder {
TextView Contact_Name, Contact_Designation, Contact_Country;
ImageView contact_avatar;
public ContactViewHolder(View itemView) {
super(itemView);
contact_avatar = itemView.findViewById(R.id.Contact_Avatar);
Contact_Name = itemView.findViewById(R.id.Contact_Name);
Contact_Designation = itemView.findViewById(R.id.Contact_Designation);
Contact_Country = itemView.findViewById(R.id.Contact_Country);
}}}

6. Now we have set all the required items now we will implement the RecyclerView in MainActivity.

ContactsRecyclerView = view.findViewById(R.id.ContactsRecyclerView);
List<ContactsModel> Contacts; Contacts = new ArrayList <>(); ContactsAdapter ContactsAdapter;
RecyclerView ContactsRecyclerView;
ContactsAdapter = new ContactsAdapter(getContext(),Contacts,ElementClickListener);
getContacts();
ContactsAdapter.notifyDataSetChanged();
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
ContactsRecyclerView.setLayoutManager(layoutManager);
ContactsRecyclerView.setItemAnimator(new DefaultItemAnimator());
ContactsRecyclerView.setAdapter(ContactsAdapter);

7. The code below is written for setting contacts into the Contacts List (just to display a data)

public void getContacts(){
for(int i=0;i<50;i++){
ContactsModel contactsModel = new ContactsModel();
contactsModel.setContact_avatar(R.drawable.ic_sentiment_very_satisfied_black_24dp);
contactsModel.setContact_Name(“Player “+i);
contactsModel.setContact_Designation(“Designation “+i);
contactsModel.setContact_Country(“Country “+i);
contactsModel.setContact_Phone(“123”+i+”565"+i);
contactsModel.setContact_Email(“player”+i+”@xyz.com”);
if(contactsModel!=null)
{
  Contacts.add(contactsModel);
}
}
ContactsAdapter.notifyDataSetChanged();
}

8. We can use card view in template_contact.xml like below. Add this in gradle file : — implementation’com.android.support:cardview-v7:27.1.1'

template_contact.xml
<?xml version=”1.0" encoding=”utf-8"?>
 <android.support.v7.widget.CardView
 xmlns:android=”http://schemas.android.com/apk/res/android"
 android:layout_width=”match_parent”
 android:layout_height=”wrap_content”
 android:layout_marginBottom=”5dp”
 android:layout_marginHorizontal=”10dp”>
 <android.support.constraint.ConstraintLayout xmlns:app=”http://schemas.android.com/apk/res-auto"
 xmlns:tools=”http://schemas.android.com/tools"
 android:layout_height=”wrap_content”
 android:layout_width=”match_parent”
 android:layout_gravity=”top”>
 
 <ImageView
 android:id=”@+id/Contact_Avatar”
 android:layout_width=”40dp”
 android:layout_height=”40dp”
 android:layout_marginBottom=”8dp”
 android:layout_marginEnd=”8dp”
 android:layout_marginStart=”16dp”
 android:background=”@color/colorAccent”
 app:layout_constraintBottom_toTopOf=”@+id/guideline2"
 app:layout_constraintEnd_toStartOf=”@+id/guideline3"
 app:layout_constraintHorizontal_bias=”0.0"
 app:layout_constraintStart_toStartOf=”parent”
 app:layout_constraintTop_toTopOf=”parent”
 app:layout_constraintVertical_bias=”0.51" />
 
 <TextView
 android:id=”@+id/Contact_Name”
 android:layout_width=”wrap_content”
 android:layout_height=”wrap_content”
 android:layout_marginBottom=”8dp”
 android:layout_marginEnd=”8dp”
 android:layout_marginStart=”8dp”
 android:text=”TextView”
 android:textSize=”14sp”
 app:layout_constraintBottom_toTopOf=”@+id/guideline2"
 app:layout_constraintEnd_toStartOf=”@+id/guideline3"
 app:layout_constraintHorizontal_bias=”0.0"
 app:layout_constraintStart_toEndOf=”@+id/Contact_Avatar”
 app:layout_constraintTop_toTopOf=”parent”
 app:layout_constraintVertical_bias=”0.32999998" />
 
 <TextView
 android:id=”@+id/Contact_Designation”
 android:layout_width=”wrap_content”
 android:layout_height=”wrap_content”
 android:layout_marginBottom=”8dp”
 android:layout_marginEnd=”8dp”
 android:layout_marginStart=”8dp”
 android:layout_marginTop=”4dp”
 android:text=”TextView”
 android:textSize=”12sp”
 app:layout_constraintBottom_toTopOf=”@+id/guideline2"
 app:layout_constraintEnd_toStartOf=”@+id/guideline3"
 app:layout_constraintHorizontal_bias=”0.0"
 app:layout_constraintStart_toEndOf=”@+id/Contact_Avatar”
 app:layout_constraintTop_toBottomOf=”@+id/Contact_Name”
 app:layout_constraintVertical_bias=”0.0" />
 
 <TextView
 android:id=”@+id/textView8"
 android:layout_width=”wrap_content”
 android:layout_height=”wrap_content”
 android:layout_marginBottom=”8dp”
 android:layout_marginEnd=”8dp”
 android:layout_marginStart=”4dp”
 android:layout_marginTop=”4dp”
 android:gravity=”center_horizontal”
 android:text=”|”
 app:layout_constraintBottom_toTopOf=”@+id/guideline2"
 app:layout_constraintEnd_toEndOf=”parent”
 app:layout_constraintHorizontal_bias=”0.0"
 app:layout_constraintStart_toEndOf=”@+id/Contact_Designation”
 app:layout_constraintTop_toBottomOf=”@+id/Contact_Name”
 app:layout_constraintVertical_bias=”0.0" />
 
 <TextView
 android:id=”@+id/Contact_Country”
 android:layout_width=”wrap_content”
 android:layout_height=”wrap_content”
 android:layout_marginBottom=”8dp”
 android:layout_marginEnd=”8dp”
 android:layout_marginStart=”4dp”
 android:layout_marginTop=”4dp”
 android:text=”TextView”
 android:textSize=”12sp”
 app:layout_constraintBottom_toTopOf=”@+id/guideline2"
 app:layout_constraintEnd_toStartOf=”@+id/guideline3"
 app:layout_constraintHorizontal_bias=”0.0"
 app:layout_constraintStart_toEndOf=”@+id/textView8"
 app:layout_constraintTop_toBottomOf=”@+id/Contact_Name”
 app:layout_constraintVertical_bias=”0.0" />
 
 <android.support.constraint.Guideline
 android:id=”@+id/guideline2"
 android:layout_width=”wrap_content”
 android:layout_height=”wrap_content”
 android:orientation=”horizontal”
 app:layout_constraintGuide_begin=”80dp” />
 
 <android.support.constraint.Guideline
 android:id=”@+id/guideline3"
 android:layout_width=”wrap_content”
 android:layout_height=”wrap_content”
 android:orientation=”vertical”
 app:layout_constraintGuide_begin=”224dp” />
 </android.support.constraint.ConstraintLayout>
 </android.support.v7.widget.CardView>

9. we are showing the list above but we can show a grid layout. In MainActivity.java

RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getContext(),2); ContactsRecyclerView.setLayoutManager(layoutManager);

10. To implement a click listener we create an interface

public interface OnElementClickListener {
     void setElementOnClickListener(int position);
}

11. In MainActivity just create an instance of this interface and pass it to the adapter

ElementClickListener = new OnElementClickListener() {
   @Override
   public void setElementOnClickListener(int position) {
      Log.i(TAG, Contacts.get(position).getContact_Name);
   }
};
ContactsAdapter = new ContactsAdapter(this, Contacts, ElementClickListener);

And write your action to be performed in this method.

12. In Adapter class we will implement a click listener and from that click listener in adapter’s onBindViewHolder() method we will call the interface method which is there in MainActivity.

Thank you for your time and I hope this article will help you. Thank you for your time. I hope this article was helpful.