ListAdapter

app/build.gradle

@@ -35,4 +35,11 @@ dependencies {
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+
+
+    def room_version = "2.2.5"
+
+    implementation "androidx.room:room-runtime:$room_version"
+    annotationProcessor "androidx.room:room-compiler:$room_version" // For Kotlin use kapt instead of annotationProcessor
+
 }

app/src/main/java/cat/cattutorial/Contact.java

@@ -0,0 +1,38 @@
+package cat.cattutorial;
+
+import androidx.annotation.NonNull;
+import androidx.room.ColumnInfo;
+import androidx.room.Entity;
+import androidx.room.PrimaryKey;
+
+@Entity(tableName = "contacts")
+public class Contact {
+    @ColumnInfo(name = "contact_name")
+    private String name;
+
+    @PrimaryKey
+    @NonNull
+    @ColumnInfo(name = "contact_number")
+    private String number;
+
+    public Contact(String name, String number) {
+        this.name = name;
+        this.number = number;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getNumber() {
+        return number;
+    }
+
+    public void setNumber(String number) {
+        this.number = number;
+    }
+}

app/src/main/java/cat/cattutorial/ContactAdapter.java

@@ -0,0 +1,56 @@
+package cat.cattutorial;
+
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.DiffUtil;
+import androidx.recyclerview.widget.ListAdapter;
+import androidx.recyclerview.widget.RecyclerView;
+
+public class ContactAdapter extends ListAdapter<Contact, ContactAdapter.ContactViewHolder> {
+
+
+    protected ContactAdapter() {
+        super(new DiffCallback());
+    }
+
+    @NonNull
+    @Override
+    public ContactViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_contact, parent, false);
+        return new ContactViewHolder(view);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull ContactViewHolder holder, int position) {
+        holder.tvName.setText(getItem(position).getName());
+    }
+
+    class ContactViewHolder extends RecyclerView.ViewHolder {
+        TextView tvName;
+        ImageView imgDelete;
+
+        public ContactViewHolder(@NonNull View itemView) {
+            super(itemView);
+            tvName = itemView.findViewById(R.id.tv_name);
+            imgDelete = itemView.findViewById(R.id.img_delete);
+        }
+    }
+
+    static class DiffCallback extends DiffUtil.ItemCallback<Contact> {
+
+        @Override
+        public boolean areItemsTheSame(@NonNull Contact oldItem, @NonNull Contact newItem) {
+            return oldItem.getName().equals(newItem.getName());
+        }
+
+        @Override
+        public boolean areContentsTheSame(@NonNull Contact oldItem, @NonNull Contact newItem) {
+            return oldItem.getNumber().equals(newItem.getNumber()) && oldItem.getName().equals(newItem.getName());
+        }
+    }
+}

app/src/main/java/cat/cattutorial/MainActivity.java

@@ -1,14 +1,51 @@
 package cat.cattutorial;
 
 import android.os.Bundle;
+import android.view.View;
 
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import cat.cattutorial.db.AppDatabase;
+
 
 public class MainActivity extends AppCompatActivity {
+
+    RecyclerView recyclerView;
+    ContactAdapter adapter = new ContactAdapter();
+    ArrayList<Contact> contacts = new ArrayList<>();
+    FloatingActionButton fab;
+
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+
+        final AppDatabase db = AppDatabase.getInstance(this);
+        List<Contact> dbContacts = db.contactDao().getContacts();
+
+        adapter.submitList(dbContacts);
+
+        recyclerView = findViewById(R.id.rv);
+        recyclerView.setAdapter(adapter);
+
+        fab = findViewById(R.id.fab);
+        fab.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                db.contactDao().insertContact(new Contact("Mohamed" + new Random().nextFloat(), new Random().nextInt()+""));
+                List<Contact> dbContacts = db.contactDao().getContacts();
+                adapter.submitList(dbContacts);
+            }
+        });
+
     }
+
 }

app/src/main/java/cat/cattutorial/db/AppDatabase.java

@@ -0,0 +1,32 @@
+package cat.cattutorial.db;
+
+import android.content.Context;
+
+import androidx.room.Database;
+import androidx.room.Room;
+import androidx.room.RoomDatabase;
+
+import cat.cattutorial.Contact;
+
+
+@Database(entities = {Contact.class}, version = 1)
+public abstract class AppDatabase extends RoomDatabase {
+
+    private static volatile AppDatabase INSTANCE;
+
+    public abstract ContactDao contactDao();
+
+    // Home Activity -> getInstance if (INSTNACE == null => True )  if (INSTANCE == null -> TRUE) -> intsance = ....
+    // Main Activity -> getInstance if (INSTNACE == null => True )  ................................................ if( INSTANCE == null -> False)
+    public static AppDatabase getInstance(Context context) {
+        if (INSTANCE == null) {
+            synchronized (AppDatabase.class) {
+                if (INSTANCE == null)
+                    INSTANCE = Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, "app.db")
+                            .allowMainThreadQueries()
+                            .build();
+            }
+        }
+        return INSTANCE;
+    }
+}

app/src/main/java/cat/cattutorial/db/ContactDao.java

@@ -0,0 +1,23 @@
+package cat.cattutorial.db;
+
+import androidx.room.Dao;
+import androidx.room.Delete;
+import androidx.room.Insert;
+import androidx.room.OnConflictStrategy;
+import androidx.room.Query;
+
+import java.util.List;
+
+import cat.cattutorial.Contact;
+
+@Dao
+public interface ContactDao {
+    @Query("SELECT * FROM contacts")
+    List<Contact> getContacts();
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    void insertContact(Contact contact);
+
+    @Delete
+    void delete(Contact contact);
+}

app/src/main/res/drawable/ic_add.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M19,13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/>
+</vector>

app/src/main/res/drawable/ic_delete.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2V7H6v12zM19,4h-3.5l-1,-1h-5l-1,1H5v2h14V4z"/>
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -6,13 +6,22 @@
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <TextView
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/rv"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
+        tools:itemCount="3"
+        tools:listitem="@layout/item_contact"/>
+
+
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/fab"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="Hello World!"
+        android:layout_margin="16dp"
+        android:src="@drawable/ic_add"
         app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        app:layout_constraintEnd_toEndOf="parent" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/item_contact.xml

@@ -0,0 +1,49 @@
+<?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="wrap_content"
+    android:layout_marginTop="16dp"
+    android:background="?attr/selectableItemBackground"
+    android:elevation="3dp">
+
+    <ImageView
+        android:id="@+id/img_contact"
+        android:layout_width="40dp"
+        android:layout_height="40dp"
+        android:layout_marginStart="16dp"
+        android:layout_marginTop="16dp"
+        android:layout_marginBottom="16dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        android:src="@drawable/img_hamdy" />
+
+    <TextView
+        android:id="@+id/tv_name"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="16dp"
+        android:fontFamily="monospace"
+        app:layout_constraintEnd_toStartOf="@id/img_delete"
+        android:maxLines="2"
+        android:ellipsize="end"
+        android:textSize="20sp"
+        app:layout_constraintBottom_toBottomOf="@id/img_contact"
+        app:layout_constraintStart_toEndOf="@id/img_contact"
+        app:layout_constraintTop_toTopOf="@id/img_contact"
+        tools:text="Mohamed Hamdy asjdkahsdjsadhjskadasjkdh" />
+
+    <ImageView
+        android:id="@+id/img_delete"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="16dp"
+        android:background="?attr/selectableItemBackground"
+        android:src="@drawable/ic_delete"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>