Simple Android grid example using RecyclerView with GridLayoutManager (like the old GridView)

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我寻月下人不归
我寻月下人不归 2020-11-22 02:03

I know that RecyclerView has replaced the functionality of the old ListView and GridView. I am looking for a very basic example that s

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  • 2020-11-22 02:32

    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);
        }
    }
    
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  • 2020-11-22 02:36

    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" />
    
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  • 2020-11-22 02:42

    Short answer

    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.

    Full 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.

    • Add dependencies to gradle
    • Add the xml layout files for the activity and for the grid cell
    • Make the RecyclerView adapter
    • Initialize the RecyclerView in your activity

    Update Gradle dependencies

    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.

    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/rvNumbers"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    
    </RelativeLayout>
    

    Create grid cell layout

    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>
    

    Create the adapter

    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

    • Although not strictly necessary, I included the functionality for listening for click events on the cells. This was available in the old GridView 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 {
    
        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

    • Notice that the activity implements the ItemClickListener that we defined in our adapter. This allows us to handle cell 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.

    Going on

    Rounded corners

    • Use a CardView

    Auto-fitting columns

    • GridLayoutManager - how to auto fit columns?

    Further study

    • Android RecyclerView with GridView GridLayoutManager example tutorial
    • Android RecyclerView Grid Layout Example
    • Learn RecyclerView With an Example in Android
    • RecyclerView: Grid with header
    • Android GridLayoutManager with RecyclerView in Material Design
    • Getting Started With RecyclerView and CardView on Android
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  • 2020-11-22 02:51

    Set in RecyclerView initialization

    recyclerView.setLayoutManager(new GridLayoutManager(this, 4));
    
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  • 2020-11-22 02:54

    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));
    
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