How to use RecyclerView with SQLite Database in Android Studio

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This simple example demonstrates using RecyclerView in combination with an SQLite database to manage and display user data. Here's a summary:

  1. MainActivity:

    • Contains input fields for user details and buttons to insert, delete, or view the data.
    • Interacts with DBHelper to manage SQLite operations.

  2. DBHelper:

    • Manages database operations like inserting, deleting, and fetching user data.
    • Uses SQLiteOpenHelper for table creation and updates.

  3. MyAdapter:

    • A custom adapter for RecyclerView that binds data fetched from the SQLite database to a UI layout (userentry.xml).

  4. Userlist Activity:

    • Displays the list of users fetched from the database in a RecyclerView.
    • Populates the RecyclerView using the MyAdapter.

  5. Layouts:

    • activity_main.xml: User interface for adding, deleting, and viewing data.
    • activity_userlist.xml: Contains the RecyclerView for displaying user data.
    • userentry.xml: A card view layout for individual items in the RecyclerView.






The code snippet for MainActivity.java is as below: 
package com.codingtutorials.recyclerviewexample;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText name, email, age;
    Button insert, view, delete;
    DBHelper DB;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        name = findViewById(R.id.name);
        email= findViewById(R.id.email);
        age = findViewById(R.id.age);
        insert = findViewById(R.id.btnInsert);
        view = findViewById(R.id.btnView);
        delete = findViewById(R.id.btnDelete);

        DB = new DBHelper(this);

        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this, Userlist.class));
            }
        });

        insert.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String nameTXT = name.getText().toString();
                String emailTXT = email.getText().toString();
                String ageTXT = age.getText().toString();

                Boolean checkinsertdata  = DB.insertuserdata(nameTXT, emailTXT, ageTXT);
                if(checkinsertdata==true)
                {
                    Toast.makeText(MainActivity.this, "New Entry Inserted", Toast.LENGTH_SHORT).show();
                }
                else
                {
                    Toast.makeText(MainActivity.this, "New Entry Not Inserted", Toast.LENGTH_SHORT).show();
                }

            }
        });


        delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String nameTXT = name.getText().toString();

                Boolean checkdeletedata  = DB.deleteuserdata(nameTXT);
                if(checkdeletedata==true)
                {
                    Toast.makeText(MainActivity.this, "Entry Deleted", Toast.LENGTH_SHORT).show();
                }
                else
                {
                    Toast.makeText(MainActivity.this, "Entry Not Deleted", Toast.LENGTH_SHORT).show();
                }

            } }); 
}}
The code snippet for DBHelper.java is as below: 
package com.codingtutorials.recyclerviewexample;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {
    public DBHelper(Context context) {
        super(context, "Userdata.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase DB) {
        DB.execSQL("create Table Userdetails(name TEXT primary key, email TEXT, age TEXT)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase DB, int i, int ii) {
        DB.execSQL("drop Table if exists Userdetails");
    }

    public Boolean insertuserdata(String name, String email, String age)
    {
        SQLiteDatabase DB = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("name", name);
        contentValues.put("email", email);
        contentValues.put("age", age);
        long result = DB.insert("Userdetails", null, contentValues);
        if(result==-1)
        {
            return  false;
        }
        else
        {
            return true;
        }
    }

    public Cursor getdata()
    {
        SQLiteDatabase DB = this.getWritableDatabase();
        Cursor cursor  = DB.rawQuery("Select * from Userdetails", null);
        return cursor;
    }



    public Boolean deleteuserdata(String name)
    {
        SQLiteDatabase DB = this.getWritableDatabase();
        Cursor cursor = DB.rawQuery("Select * from Userdetails where name = ?", new String[]{name});
        if(cursor.getCount()>0)
        {
            long result = DB.delete("Userdetails", "name=?", new String[]{name});
            if(result==-1)
            {
                return  false;
            }
            else
            {
                return true;
            }
        }
        else
        {
            return false;
        }

    }
}
The code snippet for MyAdapter.java is as below: 
package com.codingtutorials.recyclerviewexample;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class MyAdapter extends RecyclerView.Adapter {
    private Context context;
    private ArrayList name_id, email_id, age_id;

    public MyAdapter(Context context, ArrayList name_id, ArrayList email_id, ArrayList age_id) {
        this.context = context;
        this.name_id = name_id;
        this.email_id = email_id;
        this.age_id = age_id;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(context).inflate(R.layout.userentry,parent,false);
        return new MyViewHolder(v);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        holder.name_id.setText(String.valueOf(name_id.get(position)));
        holder.email_id.setText(String.valueOf(email_id.get(position)));
        holder.age_id.setText(String.valueOf(age_id.get(position)));
    }

    @Override
    public int getItemCount() {
        return name_id.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        TextView name_id, email_id, age_id;
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            name_id = itemView.findViewById(R.id.textname);
            email_id = itemView.findViewById(R.id.textemail);
            age_id = itemView.findViewById(R.id.textage);
        }
    }
}
The code snippet for Userlist.java is as below: 
package com.codingtutorials.recyclerviewexample;

import android.database.Cursor;
import android.os.Bundle;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class Userlist extends AppCompatActivity {
    RecyclerView recyclerView;
    ArrayList name, email, age;
    DBHelper DB;
    MyAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_userlist);
        DB = new DBHelper(this);
        name = new ArrayList<>();
        email = new ArrayList<>();
        age = new ArrayList<>();
        recyclerView = findViewById(R.id.recyclerview);
        adapter = new MyAdapter(this, name, email, age);
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        displaydata();
    }

    private void displaydata()
    {
        Cursor cursor = DB.getdata();
        if(cursor.getCount()==0)
        {
            Toast.makeText(Userlist.this, "No Entry Exists", Toast.LENGTH_SHORT).show();
            return;
        }
        else
        {
            while(cursor.moveToNext())
            {
                name.add(cursor.getString(0));
                email.add(cursor.getString(1));
                age.add(cursor.getString(2));
            }
        }
    }
}

Its time to make some UI now. The code snippet for activity_main.xml is below: 

<?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=".MainActivity"
    android:padding="10dp">

    <TextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Please enter your details"
        android:textSize="24dp"
        android:layout_marginTop="24dp"/>

    <EditText
        android:id="@+id/name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="24dp"
        android:layout_below="@+id/text"
        android:hint="Name"/>

    <EditText
        android:id="@+id/email"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="24dp"
        android:layout_below="@+id/name"
        android:hint="E-mail"/>

    <EditText
        android:id="@+id/age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="24dp"
        android:layout_below="@id/email"
        android:hint="Age"/>

    <Button
        android:id="@+id/btnInsert"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Insert Data"
        android:textSize="24dp"
        android:layout_below="@+id/age"
        android:layout_marginTop="20dp"/>

    <Button
        android:id="@+id/btnView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="View Data"
        android:textSize="24dp"
        android:layout_below="@+id/btnInsert"
        android:layout_marginTop="20dp"/>

    <Button
        android:id="@+id/btnDelete"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Delete Data"
        android:textSize="24dp"
        android:layout_below="@+id/btnView"
        android:layout_marginTop="20dp"/>

</RelativeLayout>

The code snippet for activity_userlist.xml is below: 

<?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=".Userlist">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>
The code snippet for userentry.xml is below: 

<?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:cardElevation="12dp"
    app:cardCornerRadius="16dp"
    android:layout_margin="16dp"
    android:backgroundTint="#efefef">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_gravity="center_vertical">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Name: "
                android:textSize="24dp"
                android:textColor="@color/black"
                style="bold"/>

            <TextView
                android:id="@+id/textname"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="24dp"
                android:textColor="@color/black"
                style="bold"/>
        </LinearLayout>

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_gravity="center_vertical">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="E-mail: "
                android:textSize="24dp"
                android:textColor="@color/black"
                style="bold"/>

            <TextView
                android:id="@+id/textemail"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="24dp"
                android:textColor="@color/black"
                style="bold"/>
        </LinearLayout>

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_gravity="center_vertical">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Age: "
                android:textSize="24dp"
                android:textColor="@color/black"
                style="bold"/>

            <TextView
                android:id="@+id/textage"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="24dp"
                android:textColor="@color/black"
                style="bold"/>
        </LinearLayout>

    </LinearLayout>

</androidx.cardview.widget.CardView>
The code snippet for AndroidManifest.xml is as below: 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.RecyclerViewExample"
        tools:targetApi="31">

        <activity
            android:name=".Userlist"
            android:exported="false" />

        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>


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