From c610364ef772ad230232252402c4f067a1fdbd45 Mon Sep 17 00:00:00 2001
From: jendib <benjamin.gam@gmail.com>
Date: Sat, 22 Nov 2014 22:43:31 +0100
Subject: [PATCH] Android: Infinite scrolling

---
 .../com/sismics/docs/MainApplication.java     |  1 -
 .../sismics/docs/adapter/DocListAdapter.java  | 15 ++++-
 .../docs/fragment/DocListFragment.java        | 59 ++++++++++++++-----
 .../docs/resource/DocumentResource.java       |  5 +-
 4 files changed, 59 insertions(+), 21 deletions(-)

diff --git a/docs-android/app/src/main/java/com/sismics/docs/MainApplication.java b/docs-android/app/src/main/java/com/sismics/docs/MainApplication.java
index 93caf893..9e354e37 100644
--- a/docs-android/app/src/main/java/com/sismics/docs/MainApplication.java
+++ b/docs-android/app/src/main/java/com/sismics/docs/MainApplication.java
@@ -23,7 +23,6 @@ public class MainApplication extends Application {
         // TODO Fullscreen preview
         // TODO Sharing
         // TODO Error feedback
-        // TODO Infinite scrolling on documents
         // TODO Searching
         // TODO Printing
 
diff --git a/docs-android/app/src/main/java/com/sismics/docs/adapter/DocListAdapter.java b/docs-android/app/src/main/java/com/sismics/docs/adapter/DocListAdapter.java
index f5c69ab9..cc4aa19c 100644
--- a/docs-android/app/src/main/java/com/sismics/docs/adapter/DocListAdapter.java
+++ b/docs-android/app/src/main/java/com/sismics/docs/adapter/DocListAdapter.java
@@ -89,11 +89,20 @@ public class DocListAdapter extends RecyclerView.Adapter<DocListAdapter.ViewHold
     }
 
     /**
-     * Update the displayed documents.
+     * Add documents to display.
+     *
      * @param documents Documents
+     * @param reset Reset the list
      */
-    public void setDocuments(JSONArray documents) {
-        this.documents = documents;
+    public void addDocuments(JSONArray documents, boolean reset) {
+        if (this.documents == null || reset) {
+            this.documents = new JSONArray();
+        }
+
+        for (int i = 0; i < documents.length(); i++) {
+            this.documents.put(documents.optJSONObject(i));
+        }
+
         notifyDataSetChanged();
     }
 }
\ No newline at end of file
diff --git a/docs-android/app/src/main/java/com/sismics/docs/fragment/DocListFragment.java b/docs-android/app/src/main/java/com/sismics/docs/fragment/DocListFragment.java
index 3f7a7091..e851bde4 100644
--- a/docs-android/app/src/main/java/com/sismics/docs/fragment/DocListFragment.java
+++ b/docs-android/app/src/main/java/com/sismics/docs/fragment/DocListFragment.java
@@ -24,26 +24,33 @@ import org.json.JSONObject;
  * @author bgamard.
  */
 public class DocListFragment extends Fragment {
-
+    /**
+     * Documents adapter.
+     */
     DocListAdapter adapter;
 
+    // Infinite scrolling things
+    private boolean loading = true;
+    private int previousTotal = 0;
+    int firstVisibleItem, visibleItemCount, totalItemCount;
+
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        // Initialize the view
         View view = inflater.inflate(R.layout.doc_list_fragment, container, false);
+
+        // Configure the RecyclerView
         RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.docList);
-
-        recyclerView.setHasFixedSize(true);
-        recyclerView.setLongClickable(true);
-
-        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
-        recyclerView.setLayoutManager(layoutManager);
-
         adapter = new DocListAdapter();
         recyclerView.setAdapter(adapter);
-
+        recyclerView.setHasFixedSize(true);
+        recyclerView.setLongClickable(true);
         recyclerView.addItemDecoration(new DividerItemDecoration(getResources().getDrawable(R.drawable.abc_list_divider_mtrl_alpha)));
 
+        // Configure the LayoutManager
+        final LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
+        recyclerView.setLayoutManager(layoutManager);
+
+        // Document opening
         recyclerView.addOnItemTouchListener(new RecyclerItemClickListener(getActivity(), new RecyclerItemClickListener.OnItemClickListener() {
             @Override
             public void onItemClick(View view, int position) {
@@ -56,8 +63,31 @@ public class DocListFragment extends Fragment {
             }
         }));
 
+        // Infinite scrolling
+        recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+                super.onScrolled(recyclerView, dx, dy);
+
+                visibleItemCount = recyclerView.getChildCount();
+                totalItemCount = layoutManager.getItemCount();
+                firstVisibleItem = layoutManager.findFirstVisibleItemPosition();
+
+                if (loading) {
+                    if (totalItemCount > previousTotal) {
+                        loading = false;
+                        previousTotal = totalItemCount;
+                    }
+                }
+                if (!loading && totalItemCount - visibleItemCount <= firstVisibleItem + 3) {
+                    loadDocuments();
+                    loading = true;
+                }
+            }
+        });
+
         // Grab the documents
-        refreshDocuments();
+        loadDocuments();
 
         return view;
     }
@@ -65,12 +95,11 @@ public class DocListFragment extends Fragment {
     /**
      * Refresh the document list.
      */
-    private void refreshDocuments() {
-        DocumentResource.list(getActivity(), new JsonHttpResponseHandler() {
+    private void loadDocuments() {
+        DocumentResource.list(getActivity(), adapter.getItemCount(), new JsonHttpResponseHandler() {
             @Override
             public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
-                adapter.setDocuments(response.optJSONArray("documents"));
-
+                adapter.addDocuments(response.optJSONArray("documents"), false);
                 if (getView() != null) {
                     getView().findViewById(R.id.progressBar).setVisibility(View.GONE);
                 }
diff --git a/docs-android/app/src/main/java/com/sismics/docs/resource/DocumentResource.java b/docs-android/app/src/main/java/com/sismics/docs/resource/DocumentResource.java
index d6680d14..a8d575db 100644
--- a/docs-android/app/src/main/java/com/sismics/docs/resource/DocumentResource.java
+++ b/docs-android/app/src/main/java/com/sismics/docs/resource/DocumentResource.java
@@ -17,11 +17,12 @@ public class DocumentResource extends BaseResource {
      * @param context Context
      * @param responseHandler Callback
      */
-    public static void list(Context context, JsonHttpResponseHandler responseHandler) {
+    public static void list(Context context, int offset, JsonHttpResponseHandler responseHandler) {
         init(context);
         
         RequestParams params = new RequestParams();
-        params.put("limit", 50);
+        params.put("limit", 20);
+        params.put("offset", offset);
         params.put("sort_column", 3);
         params.put("asc", false);
         client.get(getApiUrl(context) + "/document/list", params, responseHandler);