Android Tutorial Day 8

Learning Objective: Do you want to display custom data in listview and want to create a custom list view using AndroidRecyclerView. Here is a sample code for a quick start. Reference

You need the following Classes / Layouts / Files for making custom layouts.

Getter Setter Class
AdapterClass
Sub Layout (Row Layout)
Fragment Layout File (Here RecycleView
Fragment Java File (Here API Call Required)

Contact.Java (Getter Setter Class)

package com.at.mytestapplication.myapplication;

import java.util.ArrayList;

public class Contact {
    private String mName;
    private boolean mOnline;

    public Contact(String name, boolean online) {
        mName = name;
        mOnline = online;
    }

    public String getName() {
        return mName;
    }

    public boolean isOnline() {
        return mOnline;
    }



    private static int lastContactId = 0;

    public static ArrayList<Contact> createContactsList(int numContacts) {
        ArrayList<Contact> contacts = new ArrayList<Contact>();

        for (int i = 1; i <= numContacts; i++) {
            contacts.add(new Contact("Person " + ++lastContactId, i <= numContacts / 2));
        }

        return contacts;
    }
}

Sub Layout XML File (item_contact.xml)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="10dp"
    android:paddingBottom="10dp"
    >

    <TextView
        android:id="@+id/contact_name"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        />

    <Button
        android:id="@+id/message_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="16dp"
        android:paddingRight="16dp"
        android:textSize="10sp"
        />
</LinearLayout>

Adapter Class Java File ( ContactsAdapter.java )

package com.at.mytestapplication.myapplication;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.List;

// Create the basic adapter extending from RecyclerView.Adapter
// Note that we specify the custom ViewHolder which gives us access to our views
public class ContactsAdapter extends
        RecyclerView.Adapter<ContactsAdapter.ViewHolder> {

    // ... view holder defined above...

    // Store a member variable for the contacts
    private List<Contact> mContacts;

    // Pass in the contact array into the constructor
    public ContactsAdapter(List<Contact> contacts) {
        mContacts = contacts;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);

        // Inflate the custom layout
        View contactView = inflater.inflate(R.layout.item_contact, parent, false);

        // Return a new holder instance
        ViewHolder viewHolder = new ViewHolder(contactView);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        // Get the data model based on position
        Contact contact = mContacts.get(position);

        // Set item views based on your views and data model
        TextView textView = holder.nameTextView;
        textView.setText(contact.getName());
        Button button = holder.messageButton;
        button.setText(contact.isOnline() ? "Message" : "Offline");
        button.setEnabled(contact.isOnline());
    }

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

    // Provide a direct reference to each of the views within a data item
    // Used to cache the views within the item layout for fast access
    public class ViewHolder extends RecyclerView.ViewHolder {
        // Your holder should contain a member variable
        // for any view that will be set as you render a row
        public TextView nameTextView;
        public Button messageButton;

        // We also create a constructor that accepts the entire item row
        // and does the view lookups to find each subview
        public ViewHolder(View itemView) {
            // Stores the itemView in a public final member variable that can be used
            // to access the context from any ViewHolder instance.
            super(itemView);

            nameTextView = (TextView) itemView.findViewById(R.id.contact_name);
            messageButton = (Button) itemView.findViewById(R.id.message_button);
        }
    }
}

Fragment XML Code (fragment_forth.xml)

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rvContacts"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

<!--
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ForthFragment">

    &lt;!&ndash; TODO: Update blank fragment layout &ndash;&gt;
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment" />

</FrameLayout>-->

Fragment Java File (ForthFragment.java)

package com.at.mytestapplication.myapplication;

import android.os.Bundle;

import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.RetryPolicy;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
import org.json.JSONObject;

import java.util.ArrayList;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link ForthFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class ForthFragment extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    ArrayList<Contact> contacts;
    RecyclerView rvContacts;
    ContactsAdapter adapter;


    public ForthFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment ForthFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static ForthFragment newInstance(String param1, String param2) {
        ForthFragment fragment = new ForthFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_forth, container, false);



        // Lookup the recyclerview in activity layout
        rvContacts = (RecyclerView) view.findViewById(R.id.rvContacts);

        // Initialize contacts
        contacts = Contact.createContactsList(2);
        contacts.remove(0);
        contacts.remove(0);


        // Create adapter passing in the sample user data
        adapter = new ContactsAdapter(contacts);
        // Attach the adapter to the recyclerview to populate items
        rvContacts.setAdapter(adapter);
        // Set layout manager to position the items
        rvContacts.setLayoutManager(new LinearLayoutManager(getContext()));
        // That's all!

        callAPI();

        // Inflate the layout for this fragment
        return view;
    }

    void callAPI()
    {

        // Instantiate the RequestQueue.
        RequestQueue queue = Volley.newRequestQueue(getContext());
        String url = "https://coinmap.org/api/v1/venues/";


        // Request a string response from the provided URL.
        StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {

                        //Log.e("cs",response.toString());


                        try {

                            JSONObject obj = new JSONObject(response.toString());

                            // Log.e("cs", obj.getString("venues"));
                            JSONArray arr = new JSONArray(obj.getString("venues"));
                            int i;

                            for(i=0;i<20;i++) {
                                obj = new JSONObject(arr.get(i).toString());
                                Log.e("cs", obj.get("name").toString());

                                boolean yesno;
                                if (Integer.parseInt(obj.get("id").toString()) > 10)
                                {
                                    yesno=true;
                                }
                                else
                                {
                                    yesno=false;
                                }

                                Contact c = new Contact(obj.get("name").toString(), yesno );
                                contacts.add(c);

                            }

                            // Create adapter passing in the sample user data
                            adapter = new ContactsAdapter(contacts);
                            // Attach the adapter to the recyclerview to populate items
                            rvContacts.setAdapter(adapter);
                            // Set layout manager to position the items
                            rvContacts.setLayoutManager(new LinearLayoutManager(getContext()));



                        } catch (Throwable t) {
                            Log.e("cs", "Could not parse malformed JSON: \"" + "" + "\"");
                        }


                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e("cs",error.toString());
            }
        });

        stringRequest.setRetryPolicy(new RetryPolicy() {
            @Override
            public int getCurrentTimeout() {
                return 50000;
            }

            @Override
            public int getCurrentRetryCount() {
                return 50000;
            }

            @Override
            public void retry(VolleyError error) throws VolleyError {

            }
        });

        // Add the request to the RequestQueue.
        queue.add(stringRequest);


    }


}

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