full source commit

app/build.gradle

@@ -1,13 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 24
+    compileSdkVersion 23
     buildToolsVersion "23.0.3"
 
     defaultConfig {
         applicationId "com.sab99r.recyclerview_loadmore"
         minSdkVersion 10
-        targetSdkVersion 24
+        targetSdkVersion 23
         versionCode 1
         versionName "1.0"
     }
@@ -22,5 +22,9 @@ android {
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     testCompile 'junit:junit:4.12'
-    compile 'com.android.support:appcompat-v7:24.0.0'
+    compile 'com.android.support:appcompat-v7:23.0.0'
+    compile 'com.android.support:recyclerview-v7:23.0.0'
+    // network
+    compile 'com.squareup.retrofit2:retrofit:2.0.2'
+    compile 'com.squareup.retrofit2:converter-gson:2.0.2'
 }

app/src/main/java/com/sab99r/recyclerview_loadmore/MainActivity.java

@@ -1,13 +1,120 @@
 package com.sab99r.recyclerview_loadmore;
 
+import android.content.Context;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.util.Log;
+import android.widget.Toast;
+
+import com.sab99r.recyclerview_loadmore.network.MoviesApi;
+import com.sab99r.recyclerview_loadmore.network.ServiceGenerator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import retrofit2.Call;
+import retrofit2.Callback;
+import retrofit2.Response;
 
 public class MainActivity extends AppCompatActivity {
 
+    RecyclerView recyclerView;
+    List<MovieModel> movies;
+    MoviesAdapter adapter;
+    MoviesApi api;
+    String TAG = "MainActivity - ";
+    Context context;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+        context = this;
+        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
+        movies = new ArrayList<>();
+
+        adapter = new MoviesAdapter(this, movies);
+        adapter.setLoadMoreListener(new MoviesAdapter.OnLoadMoreListener() {
+            @Override
+            public void onLoadMore() {
+
+                recyclerView.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        int index = movies.size() - 1;
+                        loadMore(index);
+                    }
+                });
+                //Calling loadMore function in Runnable to fix the
+                // java.lang.IllegalStateException: Cannot call this method while RecyclerView is computing a layout or scrolling error
+            }
+        });
+        recyclerView.setHasFixedSize(true);
+        recyclerView.setLayoutManager(new LinearLayoutManager(context));
+        recyclerView.addItemDecoration(new VerticalLineDecorator(2));
+        recyclerView.setAdapter(adapter);
+
+        api = ServiceGenerator.createService(MoviesApi.class);
+        load(0);
+    }
+
+    private void load(int index){
+        Call<List<MovieModel>> call = api.getMovies(index);
+        call.enqueue(new Callback<List<MovieModel>>() {
+            @Override
+            public void onResponse(Call<List<MovieModel>> call, Response<List<MovieModel>> response) {
+                if(response.isSuccessful()){
+                    movies.addAll(response.body());
+                    adapter.notifyDataChanged();
+                }else{
+                    Log.e(TAG," Response Error "+String.valueOf(response.code()));
+                }
+            }
+
+            @Override
+            public void onFailure(Call<List<MovieModel>> call, Throwable t) {
+                Log.e(TAG," Response Error "+t.getMessage());
+            }
+        });
+    }
+
+    private void loadMore(int index){
+
+        //add loading progress view
+        movies.add(new MovieModel("load"));
+        adapter.notifyItemInserted(movies.size()-1);
+
+        Call<List<MovieModel>> call = api.getMovies(index);
+        call.enqueue(new Callback<List<MovieModel>>() {
+            @Override
+            public void onResponse(Call<List<MovieModel>> call, Response<List<MovieModel>> response) {
+                if(response.isSuccessful()){
+
+                    //remove loading view
+                    movies.remove(movies.size()-1);
+
+                    List<MovieModel> result = response.body();
+                    if(result.size()>0){
+                        //add loaded data
+                        movies.addAll(result);
+                    }else{//result size 0 means there is no more data available at server
+                        adapter.setMoreDataAvailable(false);
+                        //telling adapter to stop calling load more as no more server data available
+                        Toast.makeText(context,"No More Data Available",Toast.LENGTH_LONG).show();
+                    }
+                    adapter.notifyDataChanged();
+                    //should call the custom method adapter.notifyDataChanged here to get the correct loading status
+                }else{
+                    Log.e(TAG," Load More Response Error "+String.valueOf(response.code()));
+                }
+            }
+
+            @Override
+            public void onFailure(Call<List<MovieModel>> call, Throwable t) {
+                Log.e(TAG," Load More Response Error "+t.getMessage());
+            }
+        });
     }
 }

app/src/main/java/com/sab99r/recyclerview_loadmore/MovieModel.java

@@ -0,0 +1,16 @@
+package com.sab99r.recyclerview_loadmore;
+
+import java.io.Serializable;
+
+/**
+ * Created by sab99r
+ */
+public class MovieModel implements Serializable{
+    String title;
+    String rating;
+    String type;
+
+    public MovieModel(String type) {
+        this.type = type;
+    }
+}

app/src/main/java/com/sab99r/recyclerview_loadmore/MoviesAdapter.java

@@ -0,0 +1,117 @@
+package com.sab99r.recyclerview_loadmore;
+
+import android.content.Context;
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+import java.util.List;
+
+/**
+ * Created by sab99r
+ */
+public class MoviesAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
+
+    public final int TYPE_MOVIE = 0;
+    public final int TYPE_LOAD = 1;
+
+    static Context context;
+    List<MovieModel> movies;
+    OnLoadMoreListener loadMoreListener;
+    boolean isLoading = false, isMoreDataAvailable = true;
+
+    /*
+    * isLoading - to set the remote loading and complete status to fix back to back load more call
+    * isMoreDataAvailable - to set whether more data from server available or not.
+    * It will prevent useless load more request even after all the server data loaded
+    * */
+
+
+    public MoviesAdapter(Context context, List<MovieModel> movies) {
+        this.context = context;
+        this.movies = movies;
+    }
+
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+        LayoutInflater inflater = LayoutInflater.from(context);
+        if(viewType==TYPE_MOVIE){
+            return new MovieHolder(inflater.inflate(R.layout.row_movie,parent,false));
+        }else{
+            return new LoadHolder(inflater.inflate(R.layout.row_load,parent,false));
+        }
+    }
+
+    @Override
+    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
+
+        if(position>=getItemCount()-1 && isMoreDataAvailable && !isLoading && loadMoreListener!=null){
+            isLoading = true;
+            loadMoreListener.onLoadMore();
+        }
+
+        if(getItemViewType(position)==TYPE_MOVIE){
+            ((MovieHolder)holder).bindData(movies.get(position));
+        }
+        //No else part needed as load holder doesn't bind any data
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        if(movies.get(position).type.equals("movie")){
+            return TYPE_MOVIE;
+        }else{
+            return TYPE_LOAD;
+        }
+    }
+
+    @Override
+    public int getItemCount() {
+        return movies.size();
+    }
+
+    /* VIEW HOLDERS */
+
+    static class MovieHolder extends RecyclerView.ViewHolder{
+        TextView tvTitle;
+        TextView tvRating;
+        public MovieHolder(View itemView) {
+            super(itemView);
+            tvTitle=(TextView)itemView.findViewById(R.id.title);
+            tvRating=(TextView)itemView.findViewById(R.id.rating);
+        }
+
+        void bindData(MovieModel movieModel){
+            tvTitle.setText(movieModel.title);
+            tvRating.setText("Rating "+movieModel.rating);
+        }
+    }
+
+    static class LoadHolder extends RecyclerView.ViewHolder{
+        public LoadHolder(View itemView) {
+            super(itemView);
+        }
+    }
+
+    public void setMoreDataAvailable(boolean moreDataAvailable) {
+        isMoreDataAvailable = moreDataAvailable;
+    }
+
+    /* notifyDataSetChanged is final method so we can't override it
+         call adapter.notifyDataChanged(); after update the list
+         */
+    public void notifyDataChanged(){
+        notifyDataSetChanged();
+        isLoading = false;
+    }
+
+
+    interface OnLoadMoreListener{
+        void onLoadMore();
+    }
+
+    public void setLoadMoreListener(OnLoadMoreListener loadMoreListener) {
+        this.loadMoreListener = loadMoreListener;
+    }
+}

app/src/main/java/com/sab99r/recyclerview_loadmore/VerticalLineDecorator.java

@@ -0,0 +1,25 @@
+package com.sab99r.recyclerview_loadmore;
+
+import android.graphics.Rect;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+/**
+ * Created by sab99r
+ */
+public class VerticalLineDecorator extends RecyclerView.ItemDecoration {
+    private int space=0;
+
+    public VerticalLineDecorator(int space) {
+        this.space = space;
+    }
+
+    @Override
+    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
+
+        if(parent.getChildAdapterPosition(view) == 0)
+            outRect.top = space;
+
+        outRect.bottom = space;
+    }
+}

app/src/main/java/com/sab99r/recyclerview_loadmore/network/MoviesApi.java

@@ -0,0 +1,15 @@
+package com.sab99r.recyclerview_loadmore.network;
+
+import com.sab99r.recyclerview_loadmore.MovieModel;
+
+import java.util.List;
+import retrofit2.Call;
+import retrofit2.http.GET;
+import retrofit2.http.Query;
+/**
+ * Created by sab99r
+ */
+public interface MoviesApi {
+    @GET("movies.php")
+    Call<List<MovieModel>> getMovies(@Query("index") int index);
+}

app/src/main/java/com/sab99r/recyclerview_loadmore/network/ServiceGenerator.java

@@ -0,0 +1,29 @@
+package com.sab99r.recyclerview_loadmore.network;
+
+import java.util.concurrent.TimeUnit;
+import okhttp3.OkHttpClient;
+import retrofit2.Retrofit;
+import retrofit2.converter.gson.GsonConverterFactory;
+/**
+ * Created by sab99r
+ */
+public class ServiceGenerator {
+
+    public static <S> S createService(Class<S> serviceClass) {
+
+        OkHttpClient httpClient=new OkHttpClient.Builder()
+                .connectTimeout(30, TimeUnit.SECONDS)
+                .readTimeout(30, TimeUnit.SECONDS)
+                .writeTimeout(30, TimeUnit.SECONDS)
+                .build();
+
+        Retrofit retrofit = new Retrofit.Builder()
+                .baseUrl("http://www.sab99r.com/demos/api/")
+                .addConverterFactory(GsonConverterFactory.create())
+                .client(httpClient).build();
+
+        return retrofit.create(serviceClass);
+
+    }
+
+}