RecyclerView Java Tutorial Part 3

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:layout_marginBottom="100dp"
        android:background="@android:color/darker_gray"
        android:padding="4dp"
        android:scrollbars="vertical" />

    <EditText
        android:id="@+id/edittext_insert"
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentBottom="true"
        android:layout_marginStart="15dp"
        android:layout_marginBottom="25dp"
        android:inputType="number" />

    <Button
        android:id="@+id/button_insert"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@id/edittext_insert"
        android:layout_toEndOf="@id/edittext_insert"
        android:text="insert" />

    <EditText
        android:id="@+id/edittext_remove"
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@id/button_insert"
        android:layout_marginStart="65dp"
        android:layout_toEndOf="@id/button_insert"
        android:inputType="number" />

    <Button
        android:id="@+id/button_remove"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@id/edittext_remove"
        android:layout_toEndOf="@id/edittext_remove"
        android:text="remove" />

</RelativeLayout>

example_item.xml

<?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" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/textView"
            android:layout_marginStart="8dp"
            android:layout_toEndOf="@+id/imageView"
            android:text="Line 2"
            android:textSize="15sp" />

    </RelativeLayout>

</android.support.v7.widget.CardView>

ExampleAdapter.java

package com.example.application.recyclerviewproject;

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;


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 TextView mTextView2;

        public ExampleViewHolder(View itemView) {
            super(itemView);
            mImageView = itemView.findViewById(R.id.imageView);
            mTextView1 = itemView.findViewById(R.id.textView);
            mTextView2 = itemView.findViewById(R.id.textView2);
        }
    }

    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());
        holder.mTextView2.setText(currentItem.getText2());
    }

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

ExampleItem.java

package com.example.application.recyclerviewproject;

public class ExampleItem {
    private int mImageResource;
    private String mText1;
    private String mText2;

    public ExampleItem(int imageResource, String text1, String text2) {
        mImageResource = imageResource;
        mText1 = text1;
        mText2 = text2;
    }

    public int getImageResource() {
        return mImageResource;
    }

    public String getText1() {
        return mText1;
    }

    public String getText2() {
        return mText2;
    }
}

MainActivity.java

package com.example.application.recyclerviewproject;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    private ArrayList<ExampleItem> mExampleList;

    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    private Button buttonInsert;
    private Button buttonRemove;
    private EditText editTextInsert;
    private EditText editTextRemove;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        createExampleList();
        buildRecyclerView();

        buttonInsert = findViewById(R.id.button_insert);
        buttonRemove = findViewById(R.id.button_remove);
        editTextInsert = findViewById(R.id.edittext_insert);
        editTextRemove = findViewById(R.id.edittext_remove);

        buttonInsert.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int position = Integer.parseInt(editTextInsert.getText().toString());
                insertItem(position);
            }
        });

        buttonRemove.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int position = Integer.parseInt(editTextRemove.getText().toString());
                removeItem(position);
            }
        });
    }

    public void insertItem(int position) {
        mExampleList.add(position, new ExampleItem(R.drawable.ic_android, "New Item At Position" + position, "This is Line 2"));
        mAdapter.notifyItemInserted(position);
    }

    public void removeItem(int position) {
        mExampleList.remove(position);
        mAdapter.notifyItemRemoved(position);
    }

    public void createExampleList() {
        mExampleList = new ArrayList<>();
        mExampleList.add(new ExampleItem(R.drawable.ic_android, "Line 1", "Line 2"));
        mExampleList.add(new ExampleItem(R.drawable.ic_audio, "Line 3", "Line 4"));
        mExampleList.add(new ExampleItem(R.drawable.ic_sun, "Line 5", "Line 6"));
    }

    public void buildRecyclerView() {
        mRecyclerView = findViewById(R.id.recyclerView);
        mRecyclerView.setHasFixedSize(true);
        mLayoutManager = new LinearLayoutManager(this);
        mAdapter = new ExampleAdapter(mExampleList);

        mRecyclerView.setLayoutManager(mLayoutManager);
        mRecyclerView.setAdapter(mAdapter);
    }
}