Allow pull-to-refresh in thread view (closes #73)

app/src/main/java/com/keylesspalace/tusky/ThreadAdapter.java

@@ -65,20 +65,43 @@ class ThreadAdapter extends RecyclerView.Adapter implements AdapterItemRemover {
         notifyItemRemoved(position);
     }
 
-    int insertStatus(Status status) {
+    int setStatus(Status status) {
+        if (statuses.size() > 0 && statuses.get(statusIndex).equals(status)) {
+            // Do not add this status on refresh, it's already in there.
+            statuses.set(statusIndex, status);
+            return statusIndex;
+        }
         int i = statusIndex;
         statuses.add(i, status);
         notifyItemInserted(i);
         return i;
     }
 
-    void addAncestors(List<Status> ancestors) {
+    void setContext(List<Status> ancestors, List<Status> descendants) {
+        Status mainStatus = null;
+
+        // In case of refresh, remove old ancestors and descendants first. We'll remove all blindly,
+        // as we have no guarantee on their order to be the same as before
+        int old_size = statuses.size();
+        if (old_size > 0) {
+            mainStatus = statuses.get(statusIndex);
+            statuses.clear();
+            notifyItemRangeRemoved(0, old_size);
+        }
+
+        // Insert newly fetched ancestors
         statusIndex = ancestors.size();
         statuses.addAll(0, ancestors);
         notifyItemRangeInserted(0, statusIndex);
+
+        if (mainStatus != null) {
+            // In case we needed to delete everything (which is way easier than deleting
+            // everything except one), re-insert the remaining status here.
+            statuses.add(statusIndex, mainStatus);
+            notifyItemInserted(statusIndex);
         }
 
-    void addDescendants(List<Status> descendants) {
+        // Insert newly fetched descendants
         int end = statuses.size();
         statuses.addAll(descendants);
         notifyItemRangeInserted(end, descendants.size());

app/src/main/java/com/keylesspalace/tusky/ViewThreadFragment.java

@@ -21,6 +21,7 @@ import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.design.widget.Snackbar;
 import android.support.v4.content.ContextCompat;
+import android.support.v4.widget.SwipeRefreshLayout;
 import android.support.v7.widget.DividerItemDecoration;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
@@ -34,9 +35,11 @@ import com.keylesspalace.tusky.entity.StatusContext;
 import retrofit2.Call;
 import retrofit2.Callback;
 
-public class ViewThreadFragment extends SFragment implements StatusActionListener {
+public class ViewThreadFragment extends SFragment implements
+        SwipeRefreshLayout.OnRefreshListener, StatusActionListener {
     private static final String TAG = "ViewThreadFragment";
 
+    private SwipeRefreshLayout swipeRefreshLayout;
     private RecyclerView recyclerView;
     private ThreadAdapter adapter;
     private String thisThreadsStatusId;
@@ -56,6 +59,9 @@ public class ViewThreadFragment extends SFragment implements StatusActionListene
         View rootView = inflater.inflate(R.layout.fragment_view_thread, container, false);
 
         Context context = getContext();
+        swipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swipe_refresh_layout);
+        swipeRefreshLayout.setOnRefreshListener(this);
+
         recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
         recyclerView.setHasFixedSize(true);
         LinearLayoutManager layoutManager = new LinearLayoutManager(context);
@@ -86,7 +92,7 @@ public class ViewThreadFragment extends SFragment implements StatusActionListene
             @Override
             public void onResponse(Call<Status> call, retrofit2.Response<Status> response) {
                 if (response.isSuccessful()) {
-                    int position = adapter.insertStatus(response.body());
+                    int position = adapter.setStatus(response.body());
                     recyclerView.scrollToPosition(position);
                 } else {
                     onThreadRequestFailure(id);
@@ -109,10 +115,10 @@ public class ViewThreadFragment extends SFragment implements StatusActionListene
             @Override
             public void onResponse(Call<StatusContext> call, retrofit2.Response<StatusContext> response) {
                 if (response.isSuccessful()) {
+                    swipeRefreshLayout.setRefreshing(false);
                     StatusContext context = response.body();
 
-                    adapter.addAncestors(context.ancestors);
+                    adapter.setContext(context.ancestors, context.descendants);
-                    adapter.addDescendants(context.descendants);
                 } else {
                     onThreadRequestFailure(id);
                 }
@@ -128,6 +134,7 @@ public class ViewThreadFragment extends SFragment implements StatusActionListene
 
     private void onThreadRequestFailure(final String id) {
         View view = getView();
+        swipeRefreshLayout.setRefreshing(false);
         if (view != null) {
             Snackbar.make(view, R.string.error_generic, Snackbar.LENGTH_LONG)
                     .setAction(R.string.action_retry, new View.OnClickListener() {
@@ -143,6 +150,11 @@ public class ViewThreadFragment extends SFragment implements StatusActionListene
         }
     }
 
+    public void onRefresh() {
+        sendStatusRequest(thisThreadsStatusId);
+        sendThreadRequest(thisThreadsStatusId);
+    }
+
     public void onReply(int position) {
         super.reply(adapter.getItem(position));
     }

app/src/main/res/layout/fragment_view_thread.xml

@@ -1,7 +1,13 @@
 <?xml version="1.0" encoding="utf-8"?>
+<android.support.v4.widget.SwipeRefreshLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/swipe_refresh_layout"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
     <android.support.v7.widget.RecyclerView
         xmlns:android="http://schemas.android.com/apk/res/android"
         android:id="@+id/recycler_view"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:scrollbars="vertical" />
+</android.support.v4.widget.SwipeRefreshLayout>