switch to asyncdiff implementation of pager adapter

4 files changed, 75 insertions, 26 deletions

diff --git a/org.fox.ttrss/src/main/java/org/fox/ttrss/ArticlePager.java b/org.fox.ttrss/src/main/java/org/fox/ttrss/ArticlePager.java
index 016bc370..46c42768 100755
--- a/org.fox.ttrss/src/main/java/org/fox/ttrss/ArticlePager.java
+++ b/org.fox.ttrss/src/main/java/org/fox/ttrss/ArticlePager.java
@@ -17,11 +17,13 @@ import androidx.viewpager2.widget.ViewPager2;
 import org.fox.ttrss.types.Article;
 import org.fox.ttrss.types.ArticleList;
 import org.fox.ttrss.types.Feed;
+import org.fox.ttrss.util.DiffFragmentStateAdapter;
+import org.fox.ttrss.util.HeadlinesDiffItemCallback;
 import org.fox.ttrss.util.HeadlinesDiffUtilCallback;
 
 public class ArticlePager extends androidx.fragment.app.Fragment {
 
-	private final String TAG = "ArticlePager";
+	private final String TAG = this.getClass().getSimpleName();
 	private PagerAdapter m_adapter;
 	private HeadlinesEventListener m_listener;
 	private int m_articleId;
@@ -29,44 +31,39 @@ public class ArticlePager extends androidx.fragment.app.Fragment {
 	private Feed m_feed;
 	private ViewPager2 m_pager;
 
-	private static class PagerAdapter extends FragmentStateAdapter {
-		private ArticleList m_articles = new ArticleList();
+	private class PagerAdapter extends DiffFragmentStateAdapter<Article> {
 
-		public PagerAdapter(@NonNull Fragment fragment, ArticleList initialArticles) {
-			super(fragment);
+		public PagerAdapter(@NonNull Fragment fragment) {
+			super(fragment, new HeadlinesDiffItemCallback());
 
-			m_articles.clear();
-			m_articles.addAll(initialArticles);
+			syncToSharedArticles();
 		}
 
 		private void syncToSharedArticles() {
+			Log.d(TAG, "syncToSharedArticles");
+
 			ArticleList tmp = new ArticleList();
 			tmp.addAll(Application.getArticles());
 
-			DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new HeadlinesDiffUtilCallback(m_articles, tmp));
+			Log.d(TAG, "shared size=" + Application.getArticles().size() + " local size=" + getItemCount());
 
-			diffResult.dispatchUpdatesTo(this);
+			for (Article a : tmp) {
+				Log.d(TAG, a.title);
+			}
 
-			m_articles.clear();
-			m_articles.addAll(tmp);
+			submitList(tmp);
 		}
 
 		@Override
 		@NonNull
 		public Fragment createFragment(int position) {
-			Article article = m_articles.get(position);
+			Article article = getItem(position);
 
 			ArticleFragment af = new ArticleFragment();
 			af.initialize(article);
 
 			return af;
 		}
-
-		@Override
-		public int getItemCount() {
-			return m_articles.size();
-		}
-
 	}
 		
 	public void initialize(int articleId, Feed feed) {
@@ -98,7 +95,7 @@ public class ArticlePager extends androidx.fragment.app.Fragment {
 	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {    	
 		View view = inflater.inflate(R.layout.fragment_article_pager, container, false);
 
-		m_adapter = new PagerAdapter(this, Application.getArticles());
+		m_adapter = new PagerAdapter(this);
 		
 		m_pager = view.findViewById(R.id.article_pager);
 
@@ -186,10 +183,6 @@ public class ArticlePager extends androidx.fragment.app.Fragment {
 			m_adapter.notifyItemChanged(position);
 	}
 
-	public void notifyUpdated() {
-		m_adapter.notifyDataSetChanged();
-	}
-
 	public void syncToSharedArticles() {
 		if (m_adapter != null)
 			m_adapter.syncToSharedArticles();
diff --git a/org.fox.ttrss/src/main/java/org/fox/ttrss/DetailActivity.java b/org.fox.ttrss/src/main/java/org/fox/ttrss/DetailActivity.java
index b0f5796d..ed237fed 100755
--- a/org.fox.ttrss/src/main/java/org/fox/ttrss/DetailActivity.java
+++ b/org.fox.ttrss/src/main/java/org/fox/ttrss/DetailActivity.java
@@ -299,11 +299,11 @@ public class DetailActivity extends OnlineActivity implements HeadlinesEventList
 		HeadlinesFragment hf = (HeadlinesFragment) getSupportFragmentManager().findFragmentByTag(FRAG_HEADLINES);
 		ArticlePager ap = (ArticlePager) getSupportFragmentManager().findFragmentByTag(FRAG_ARTICLE);
 
-        if (ap != null) {
+		if (ap != null) {
             ap.syncToSharedArticles();
         }
 
-		if (hf != null) {
+		/* if (hf != null) {
 			Article article = Application.getArticles().getById(hf.getActiveArticleId());
 						
 			if (article == null && !Application.getArticles().isEmpty()) {
@@ -321,7 +321,7 @@ public class DetailActivity extends OnlineActivity implements HeadlinesEventList
 				ft.replace(R.id.article_fragment, af, FRAG_ARTICLE);
 				ft.commitAllowingStateLoss();
 			}
-		}
+		} */
 	}
 	
 	@Override
diff --git a/org.fox.ttrss/src/main/java/org/fox/ttrss/MasterActivity.java b/org.fox.ttrss/src/main/java/org/fox/ttrss/MasterActivity.java
index fcca41bb..452c720b 100755
--- a/org.fox.ttrss/src/main/java/org/fox/ttrss/MasterActivity.java
+++ b/org.fox.ttrss/src/main/java/org/fox/ttrss/MasterActivity.java
@@ -520,6 +520,8 @@ public class MasterActivity extends OnlineActivity implements HeadlinesEventList
 	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 		super.onActivityResult(requestCode, resultCode, data);
 
+		Log.d(TAG, "onActivityResult:" + requestCode + " "+ resultCode + " " + data);
+
 		if (requestCode == HEADLINES_REQUEST) {
 			HeadlinesFragment hf = (HeadlinesFragment) getSupportFragmentManager().findFragmentByTag(FRAG_HEADLINES);
 
diff --git a/org.fox.ttrss/src/main/java/org/fox/ttrss/util/DiffFragmentStateAdapter.java b/org.fox.ttrss/src/main/java/org/fox/ttrss/util/DiffFragmentStateAdapter.java
new file mode 100644
index 00000000..c423b02d
--- /dev/null
+++ b/org.fox.ttrss/src/main/java/org/fox/ttrss/util/DiffFragmentStateAdapter.java
@@ -0,0 +1,54 @@
+package org.fox.ttrss.util;
+
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentActivity;
+import androidx.fragment.app.FragmentManager;
+import androidx.lifecycle.Lifecycle;
+import androidx.recyclerview.widget.AsyncListDiffer;
+import androidx.recyclerview.widget.DiffUtil;
+import androidx.viewpager2.adapter.FragmentStateAdapter;
+
+import java.util.List;
+
+// https://gist.github.com/Gnzlt/7e8a23ba0c3b046ed33c824b284d7270
+public abstract class DiffFragmentStateAdapter<T> extends FragmentStateAdapter {
+
+    private final AsyncListDiffer<T> differ;
+
+    protected DiffFragmentStateAdapter(FragmentActivity fragmentActivity, DiffUtil.ItemCallback<T> diffCallback) {
+        super(fragmentActivity);
+        differ = new AsyncListDiffer<>(this, diffCallback);
+    }
+
+    protected DiffFragmentStateAdapter(Fragment fragment, DiffUtil.ItemCallback<T> diffCallback) {
+        super(fragment);
+        differ = new AsyncListDiffer<>(this, diffCallback);
+    }
+
+    protected DiffFragmentStateAdapter(FragmentManager fragmentManager, Lifecycle lifecycle, DiffUtil.ItemCallback<T> diffCallback) {
+        super(fragmentManager, lifecycle);
+        differ = new AsyncListDiffer<>(this, diffCallback);
+    }
+
+    public void submitList(List<T> list, Runnable commitCallback) {
+        differ.submitList(list, commitCallback);
+    }
+
+    public void submitList(List<T> list) {
+        differ.submitList(list, null);
+    }
+
+    public List<T> getCurrentList() {
+        return differ.getCurrentList();
+    }
+
+    protected T getItem(int position) {
+        return differ.getCurrentList().get(position);
+    }
+
+    @Override
+    public int getItemCount() {
+        return differ.getCurrentList().size();
+    }
+}
+