I know that RecyclerView
has replaced the functionality of the old ListView
and GridView
. I am looking for a very basic example that s
Although I do like and appreciate Suragch's answer, I would like to leave a note because I found that coding the Adapter (MyRecyclerViewAdapter
) to define and expose the Listener method onItemClick
isn't the best way to do it, due to not using class encapsulation correctly. So my suggestion is to let the Adapter handle the Listening operations solely (that's his purpose!) and separate those from the Activity that uses the Adapter (MainActivity
). So this is how I would set the Adapter class:
MyRecyclerViewAdapter.java
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {
private String[] mData = new String[0];
private LayoutInflater mInflater;
// Data is passed into the constructor
public MyRecyclerViewAdapter(Context context, String[] data) {
this.mInflater = LayoutInflater.from(context);
this.mData = data;
}
// Inflates the cell layout from xml when needed
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
// Binds the data to the textview in each cell
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
String animal = mData[position];
holder.myTextView.setText(animal);
}
// Total number of cells
@Override
public int getItemCount() {
return mData.length;
}
// Stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView myTextView;
public ViewHolder(View itemView) {
super(itemView);
myTextView = (TextView) itemView.findViewById(R.id.info_text);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
onItemClick(view, getAdapterPosition());
}
}
// Convenience method for getting data at click position
public String getItem(int id) {
return mData[id];
}
// Method that executes your code for the action received
public void onItemClick(View view, int position) {
Log.i("TAG", "You clicked number " + getItem(position).toString() + ", which is at cell position " + position);
}
}
Please note the onItemClick
method now defined in MyRecyclerViewAdapter
that is the place where you would want to code your tasks for the event/action received.
There is only a small change to be done in order to complete this transformation: the Activity doesn't need to implement MyRecyclerViewAdapter.ItemClickListener
anymore, because now that is done completely by the Adapter. This would then be the final modification:
MainActivity.java
public class MainActivity extends AppCompatActivity {
MyRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// data to populate the RecyclerView with
String[] data = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48"};
// set up the RecyclerView
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.rvNumbers);
int numberOfColumns = 6;
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
adapter = new MyRecyclerViewAdapter(this, data);
adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
}
}
This is a simple way from XML only
spanCount for number of columns
layoutManager for making it grid or linear(Vertical or Horizontal)
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/personListRecyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
app:spanCount="2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
For those who are already familiar with setting up a RecyclerView to make a list, the good news is that making a grid is largely the same. You just use a GridLayoutManager
instead of a LinearLayoutManager
when you set the RecyclerView
up.
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
If you need more help than that, then check out the following example.
The following is a minimal example that will look like the image below.
Start with an empty activity. You will perform the following tasks to add the RecyclerView
grid. All you need to do is copy and paste the code in each section. Later you can customize it to fit your needs.
Make sure the following dependencies are in your app gradle.build
file:
compile 'com.android.support:appcompat-v7:27.1.1'
compile 'com.android.support:recyclerview-v7:27.1.1'
You can update the version numbers to whatever is the most current.
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/rvNumbers"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
Each cell in our RecyclerView
grid is only going to have a single 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:orientation="horizontal"
android:padding="5dp"
android:layout_width="50dp"
android:layout_height="50dp">
<TextView
android:id="@+id/info_text"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:background="@color/colorAccent"/>
</LinearLayout>
The RecyclerView
needs an adapter to populate the views in each cell with your data. Create a new java file.
MyRecyclerViewAdapter.java
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {
private String[] mData;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
MyRecyclerViewAdapter(Context context, String[] data) {
this.mInflater = LayoutInflater.from(context);
this.mData = data;
}
// inflates the cell 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 TextView in each cell
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
holder.myTextView.setText(mData[position]);
}
// total number of cells
@Override
public int getItemCount() {
return mData.length;
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView myTextView;
ViewHolder(View itemView) {
super(itemView);
myTextView = itemView.findViewById(R.id.info_text);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// convenience method for getting data at click position
String getItem(int id) {
return mData[id];
}
// allows clicks events to be caught
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
GridView
and is a common need. You can remove this code if you don't need it.Add the following code to your main activity.
MainActivity.java
public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {
MyRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// data to populate the RecyclerView with
String[] data = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48"};
// set up the RecyclerView
RecyclerView recyclerView = findViewById(R.id.rvNumbers);
int numberOfColumns = 6;
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
adapter = new MyRecyclerViewAdapter(this, data);
adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
}
@Override
public void onItemClick(View view, int position) {
Log.i("TAG", "You clicked number " + adapter.getItem(position) + ", which is at cell position " + position);
}
}
Notes
ItemClickListener
that we defined in our adapter. This allows us to handle cell click events in onItemClick
.That's it. You should be able to run your project now and get something similar to the image at the top.
Rounded corners
Auto-fitting columns
Set in RecyclerView
initialization
recyclerView.setLayoutManager(new GridLayoutManager(this, 4));
You should set your RecyclerView
LayoutManager
to Gridlayout mode. Just change your code when you want to set your RecyclerView
LayoutManager
:
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), numberOfColumns));