Improved class file structure.

Author: jainkuniya

app/src/main/java/com/zulip/android/activities/MessageListFragment.java

@@ -53,7 +53,7 @@
 import com.zulip.android.util.ZLog;
 import com.zulip.android.viewholders.HeaderSpaceItemDecoration;
 import com.zulip.android.viewholders.stickyheaders.StickyLayoutManager;
-import com.zulip.android.viewholders.stickyheaders.interfaces.RetrieveHeaderView;
+import com.zulip.android.viewholders.stickyheaders.RetrieveHeaderView;
 import com.zulip.android.viewholders.stickyheaders.interfaces.StickyHeaderListener;
 
 import org.json.JSONObject;
@@ -62,7 +62,6 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Calendar;
-import java.util.Date;
 import java.util.List;
 
 import retrofit2.Call;

app/src/main/java/com/zulip/android/activities/RecyclerMessageAdapter.java

@@ -52,7 +52,7 @@
 import com.zulip.android.viewholders.LoadingHolder;
 import com.zulip.android.viewholders.MessageHeaderParent;
 import com.zulip.android.viewholders.MessageHolder;
-import com.zulip.android.viewholders.stickyheaders.interfaces.RetrieveHeaderView;
+import com.zulip.android.viewholders.stickyheaders.RetrieveHeaderView;
 import com.zulip.android.viewholders.stickyheaders.interfaces.StickyHeaderHandler;
 
 import java.io.IOException;

app/src/main/java/com/zulip/android/viewholders/stickyheaders/GetStickyHeaderPosition.java

@@ -14,7 +14,6 @@
 import android.view.ViewTreeObserver;
 
 
-import com.zulip.android.viewholders.stickyheaders.interfaces.RetrieveHeaderView;
 import com.zulip.android.viewholders.stickyheaders.interfaces.StickyHeaderListener;
 
 import java.util.List;
@@ -58,7 +57,7 @@ void setHeaderPositions(List<Integer> headerPositions) {
         this.headerPositions = headerPositions;
     }
 
-    RecyclerView.ViewHolder updateHeaderState(int firstVisiblePosition, Map<Integer, View> visibleHeaders,
+    void updateHeaderState(int firstVisiblePosition, Map<Integer, View> visibleHeaders,
                                               RetrieveHeaderView retrieveHeaderView) {
         int headerPositionToShow = getHeaderPositionToShow(
                 firstVisiblePosition, visibleHeaders.get(firstVisiblePosition));
@@ -70,12 +69,11 @@ RecyclerView.ViewHolder updateHeaderState(int firstVisiblePosition, Map<Integer,
                 lastBoundPosition = INVALID_POSITION;
             } else {
                 // We don't want to attach yet if header view is not at edge
-                if (checkMargins && headerAwayFromEdge(headerToCopy)) return null;
+                if (checkMargins && headerAwayFromEdge(headerToCopy)) return;
                 RecyclerView.ViewHolder viewHolder =
                         retrieveHeaderView.getViewHolderForPosition(headerPositionToShow);
                 attachHeader(viewHolder, headerPositionToShow);
                 lastBoundPosition = headerPositionToShow;
-                return viewHolder;
             }
         } else if (checkMargins) {
             /*
@@ -88,7 +86,6 @@ RecyclerView.ViewHolder updateHeaderState(int firstVisiblePosition, Map<Integer,
             }
         }
         checkHeaderPositions(visibleHeaders);
-        return null;
     }
 
     // This checks visible headers and their positions to determine if the sticky header needs

app/src/main/java/com/zulip/android/viewholders/stickyheaders/RetrieveHeaderView.java

@@ -0,0 +1,38 @@
+package com.zulip.android.viewholders.stickyheaders;
+
+import android.support.design.widget.CoordinatorLayout;
+import android.support.v7.widget.RecyclerView;
+import android.view.ViewGroup;
+
+import com.zulip.android.ZulipApp;
+
+public class RetrieveHeaderView {
+
+    public static int DEFAULT_VIEW_TYPE = -1;
+
+    private final RecyclerView recyclerView;
+
+    private RecyclerView.ViewHolder currentViewHolder;
+    private int currentViewType;
+
+    RetrieveHeaderView(RecyclerView recyclerView) {
+        this.recyclerView = recyclerView;
+        this.currentViewType = DEFAULT_VIEW_TYPE;
+    }
+
+    RecyclerView.ViewHolder getViewHolderForPosition(int position) {
+        if (currentViewType != recyclerView.getAdapter().getItemViewType(position)) {
+            currentViewType = recyclerView.getAdapter().getItemViewType(position);
+            currentViewHolder = recyclerView.getAdapter().createViewHolder(
+                    (ViewGroup) recyclerView.getParent(), currentViewType);
+        }
+        //set top margin for sticky header to 0 as in message_header.xml it is present which is only required when header is in between of messages
+        CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) currentViewHolder.itemView.getLayoutParams();
+        layoutParams.setMargins(0, ZulipApp.get().getZulipActivity().getFloatingHeaderTopMargin(), 0, 0);
+
+        //set viewHolder in ZulipActivity
+        //adjust it when message list get scrolled
+        ZulipApp.get().getZulipActivity().setViewHolder(currentViewHolder);
+        return currentViewHolder;
+    }
+}

app/src/main/java/com/zulip/android/viewholders/stickyheaders/StickyLayoutManager.java

@@ -4,16 +4,13 @@
 
 import android.content.Context;
 import android.support.annotation.Nullable;
-import android.support.design.widget.CoordinatorLayout;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.Log;
 import android.view.View;
 
 import com.zulip.android.ZulipApp;
-import com.zulip.android.util.RemoveViewsOnScroll;
 import com.zulip.android.viewholders.MessageHeaderParent;
-import com.zulip.android.viewholders.stickyheaders.interfaces.RetrieveHeaderView;
 import com.zulip.android.viewholders.stickyheaders.interfaces.StickyHeaderHandler;
 import com.zulip.android.viewholders.stickyheaders.interfaces.StickyHeaderListener;
 
@@ -27,7 +24,7 @@ public class StickyLayoutManager extends LinearLayoutManager {
     private GetStickyHeaderPosition positioner;
     private StickyHeaderHandler headerHandler;
     private List<Integer> headerPositions;
-    private RetrieveHeaderView.RecyclerRetrieveHeaderView viewRetriever;
+    private RetrieveHeaderView viewRetriever;
     private RecyclerView recyclerView;
     @Nullable
     private StickyHeaderListener listener;
@@ -78,11 +75,8 @@ private void cacheHeaderPositions() {
     public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
         int scroll = super.scrollVerticallyBy(dy, recycler, state);
         if (Math.abs(scroll) > 0) {
-            RecyclerView.ViewHolder viewHolder = positioner.updateHeaderState(
+            positioner.updateHeaderState(
                     findFirstVisibleItemPosition(), getVisibleHeaders(), viewRetriever);
-            if (viewHolder != null) {
-                ZulipApp.get().getZulipActivity().setViewHolder(viewHolder);
-            }
         }
         return scroll;
     }
@@ -126,7 +120,7 @@ public void setStickyHeaderListener(@Nullable StickyHeaderListener listener) {
     public void onAttachedToWindow(RecyclerView view) {
         super.onAttachedToWindow(view);
         recyclerView = view;
-        viewRetriever = new RetrieveHeaderView.RecyclerRetrieveHeaderView(recyclerView);
+        viewRetriever = new RetrieveHeaderView(recyclerView);
         positioner = new GetStickyHeaderPosition(recyclerView);
         positioner.setListener(listener);
     }

app/src/main/java/com/zulip/android/viewholders/stickyheaders/interfaces/RetrieveHeaderView.java

@@ -1,5 +1,7 @@
 package com.zulip.android.viewholders.stickyheaders.interfaces;
 
+import com.zulip.android.viewholders.stickyheaders.RetrieveHeaderView;
+
 /**
  * A listener that can be set by calling {@link com.zulip.android.viewholders.stickyheaders.StickyLayoutManager#setStickyHeaderListener(StickyHeaderListener)}
  * <p>