How to build a horizontal ListView with RecyclerView How to build a horizontal ListView with RecyclerView android android

How to build a horizontal ListView with RecyclerView


Is there a better way to implement this now with RecyclerView now?

Yes.

When you use a RecyclerView, you need to specify a LayoutManager that is responsible for laying out each item in the view. The LinearLayoutManager allows you to specify an orientation, just like a normal LinearLayout would.

To create a horizontal list with RecyclerView, you might do something like this:

LinearLayoutManager layoutManager    = new LinearLayoutManager(requireContext(), LinearLayoutManager.HORIZONTAL, false);RecyclerView myList = (RecyclerView) findViewById(R.id.my_recycler_view);myList.setLayoutManager(layoutManager);


 <android.support.v7.widget.RecyclerView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:orientation="horizontal"        app:layoutManager="android.support.v7.widget.LinearLayoutManager" />


Complete example

enter image description here

The only real difference between a vertical RecyclerView and a horizontal one is how you set up the LinearLayoutManager. Here is the code snippet. The full example is below.

LinearLayoutManager horizontalLayoutManagaer = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);recyclerView.setLayoutManager(horizontalLayoutManagaer);

This fuller example is modeled after my vertical RecyclerView answer.

Update Gradle dependencies

Make sure the following dependencies are in your app gradle.build file:

implementation 'com.android.support:appcompat-v7:27.1.1'implementation 'com.android.support:recyclerview-v7:27.1.1'

You can update the version numbers to whatever is the most current.

Create activity layout

Add the RecyclerView to your xml layout.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView        android:id="@+id/rvAnimals"        android:layout_width="match_parent"        android:layout_height="match_parent"/></RelativeLayout>

Create item layout

Each item in our RecyclerView is going to have a single a colored View over a TextView. Create a new layout resource file.

recyclerview_item.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="wrap_content"    android:layout_height="match_parent"    android:orientation="vertical"    android:padding="10dp">    <View        android:id="@+id/colorView"        android:layout_width="100dp"        android:layout_height="100dp"/>    <TextView        android:id="@+id/tvAnimalName"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textSize="20sp"/></LinearLayout>

Create the adapter

The RecyclerView needs an adapter to populate the views in each row (horizontal item) with your data. Create a new java file.

MyRecyclerViewAdapter.java

public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {    private List<Integer> mViewColors;    private List<String> mAnimals;    private LayoutInflater mInflater;    private ItemClickListener mClickListener;    // data is passed into the constructor    MyRecyclerViewAdapter(Context context, List<Integer> colors, List<String> animals) {        this.mInflater = LayoutInflater.from(context);        this.mViewColors = colors;        this.mAnimals = animals;    }    // inflates the row layout from xml when needed    @Override    @NonNull    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {        View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);        return new ViewHolder(view);    }    // binds the data to the view and textview in each row    @Override    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {        int color = mViewColors.get(position);        String animal = mAnimals.get(position);        holder.myView.setBackgroundColor(color);        holder.myTextView.setText(animal);    }    // total number of rows    @Override    public int getItemCount() {        return mAnimals.size();    }    // stores and recycles views as they are scrolled off screen    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {        View myView;        TextView myTextView;        ViewHolder(View itemView) {            super(itemView);            myView = itemView.findViewById(R.id.colorView);            myTextView = itemView.findViewById(R.id.tvAnimalName);            itemView.setOnClickListener(this);        }        @Override        public void onClick(View view) {            if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());        }    }    // convenience method for getting data at click position    public String getItem(int id) {        return mAnimals.get(id);    }    // allows clicks events to be caught    public void setClickListener(ItemClickListener itemClickListener) {        this.mClickListener = itemClickListener;    }    // parent activity will implement this method to respond to click events    public interface ItemClickListener {        void onItemClick(View view, int position);    }}

Notes

  • Although not strictly necessary, I included the functionality for listening for click events on the items. This was available in the old ListViews and is a common need. You can remove this code if you don't need it.

Initialize RecyclerView in Activity

Add the following code to your main activity.

MainActivity.java

public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {    private MyRecyclerViewAdapter adapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // data to populate the RecyclerView with        ArrayList<Integer> viewColors = new ArrayList<>();        viewColors.add(Color.BLUE);        viewColors.add(Color.YELLOW);        viewColors.add(Color.MAGENTA);        viewColors.add(Color.RED);        viewColors.add(Color.BLACK);        ArrayList<String> animalNames = new ArrayList<>();        animalNames.add("Horse");        animalNames.add("Cow");        animalNames.add("Camel");        animalNames.add("Sheep");        animalNames.add("Goat");        // set up the RecyclerView        RecyclerView recyclerView = findViewById(R.id.rvAnimals);        LinearLayoutManager horizontalLayoutManager                = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);        recyclerView.setLayoutManager(horizontalLayoutManager);        adapter = new MyRecyclerViewAdapter(this, viewColors, animalNames);        adapter.setClickListener(this);        recyclerView.setAdapter(adapter);    }    @Override    public void onItemClick(View view, int position) {        Toast.makeText(this, "You clicked " + adapter.getItem(position) + " on item position " + position, Toast.LENGTH_SHORT).show();    }}

Notes

  • Notice that the activity implements the ItemClickListener that we defined in our adapter. This allows us to handle item click events in onItemClick.

Finished

That's it. You should be able to run your project now and get something similar to the image at the top.

Notes