From 12e4975e6663ad8ebb4e3c22db7e525f6fc93fcb Mon Sep 17 00:00:00 2001
From: emanuele-f <black.silver@hotmail.it>
Date: Sun, 2 Jan 2022 22:18:18 +0100
Subject: [PATCH] Workaround for crash in RecyclerView dispatchLayout

In some rare cases the RecyclerView dispatchLayout crashes with an IndexOutOfBoundsException. This seems a bug in the androidx library. The provided workaround should fix it.
---
 .../adapters/ConnectionsAdapter.java          |  7 ++++++-
 .../fragments/AppsFragment.java               |  4 +---
 .../fragments/ConnectionsFragment.java        |  5 ++---
 .../remote_capture/views/AppsListView.java    |  3 +--
 .../views/EmptyRecyclerView.java              | 20 +++++++++++++++++++
 5 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/app/src/main/java/com/emanuelef/remote_capture/adapters/ConnectionsAdapter.java b/app/src/main/java/com/emanuelef/remote_capture/adapters/ConnectionsAdapter.java
index a68a0224..21ddefee 100644
--- a/app/src/main/java/com/emanuelef/remote_capture/adapters/ConnectionsAdapter.java
+++ b/app/src/main/java/com/emanuelef/remote_capture/adapters/ConnectionsAdapter.java
@@ -112,7 +112,7 @@ public class ConnectionsAdapter extends RecyclerView.Adapter<ConnectionsAdapter.
             appIcon = ((app != null) && (app.getIcon() != null)) ? Objects.requireNonNull(app.getIcon().getConstantState()).newDrawable() : unknownIcon;
             icon.setImageDrawable(appIcon);
 
-            if(conn.info.length() > 0)
+            if((conn.info != null) && (conn.info.length() > 0))
                 remote.setText(conn.info);
             else
                 remote.setText(conn.dst_ip);
@@ -249,12 +249,14 @@ public class ConnectionsAdapter extends RecyclerView.Adapter<ConnectionsAdapter.
 
     @Override
     public void connectionsChanges(int num_connetions) {
+        //Log.d(TAG, "connectionsChanges: " + num_connetions + " connections");
         mUnfilteredItemsCount = num_connetions;
         refreshFilteredConnections();
     }
 
     @Override
     public void connectionsAdded(int start, ConnectionDescriptor []conns) {
+        //Log.d(TAG, "connectionsAdded: at " + start + ", " + conns.length + " connections");
         mUnfilteredItemsCount += conns.length;
 
         if(mFilteredConn == null) {
@@ -281,6 +283,7 @@ public class ConnectionsAdapter extends RecyclerView.Adapter<ConnectionsAdapter.
 
     @Override
     public void connectionsRemoved(int start, ConnectionDescriptor []conns) {
+        //Log.d(TAG, "connectionsRemoved: at " + start + ", " + conns.length + " connections");
         mUnfilteredItemsCount -= conns.length;
 
         if(mFilteredConn == null) {
@@ -306,6 +309,8 @@ public class ConnectionsAdapter extends RecyclerView.Adapter<ConnectionsAdapter.
 
     @Override
     public void connectionsUpdated(int[] positions) {
+        //Log.d(TAG, "connectionsUpdated: " + positions.length + " connections");
+
         if(mFilteredConn == null) {
             for(int pos : positions)
                 notifyItemChanged(pos);
diff --git a/app/src/main/java/com/emanuelef/remote_capture/fragments/AppsFragment.java b/app/src/main/java/com/emanuelef/remote_capture/fragments/AppsFragment.java
index ca2b7cca..6cafa488 100644
--- a/app/src/main/java/com/emanuelef/remote_capture/fragments/AppsFragment.java
+++ b/app/src/main/java/com/emanuelef/remote_capture/fragments/AppsFragment.java
@@ -35,7 +35,6 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-import androidx.recyclerview.widget.LinearLayoutManager;
 
 import com.emanuelef.remote_capture.CaptureService;
 import com.emanuelef.remote_capture.ConnectionsRegister;
@@ -78,8 +77,7 @@ public class AppsFragment extends Fragment implements ConnectionsListener {
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         mRecyclerView = view.findViewById(R.id.apps_stats_view);
-        LinearLayoutManager layoutMan = new LinearLayoutManager(getContext());
-        mRecyclerView.setLayoutManager(layoutMan);
+        mRecyclerView.setLayoutManager(new EmptyRecyclerView.MyLinearLayoutManager(getContext()));
 
         mAdapter = new AppsStatsAdapter(getContext());
         doRefreshApps();
diff --git a/app/src/main/java/com/emanuelef/remote_capture/fragments/ConnectionsFragment.java b/app/src/main/java/com/emanuelef/remote_capture/fragments/ConnectionsFragment.java
index 47fe2b87..3f29aa7f 100644
--- a/app/src/main/java/com/emanuelef/remote_capture/fragments/ConnectionsFragment.java
+++ b/app/src/main/java/com/emanuelef/remote_capture/fragments/ConnectionsFragment.java
@@ -49,7 +49,6 @@ import androidx.appcompat.widget.SearchView;
 import androidx.fragment.app.Fragment;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 import androidx.recyclerview.widget.DividerItemDecoration;
-import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.emanuelef.remote_capture.AppsResolver;
@@ -174,7 +173,7 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
         mFabDown = view.findViewById(R.id.fabDown);
         mRecyclerView = view.findViewById(R.id.connections_view);
         mOldConnectionsText = view.findViewById(R.id.old_connections_notice);
-        LinearLayoutManager layoutMan = new LinearLayoutManager(requireContext());
+        EmptyRecyclerView.MyLinearLayoutManager layoutMan = new EmptyRecyclerView.MyLinearLayoutManager(requireContext());
         mRecyclerView.setLayoutManager(layoutMan);
         mApps = new AppsResolver(requireContext());
 
@@ -512,7 +511,7 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
     }
 
     private void recheckScroll() {
-        final LinearLayoutManager layoutMan = (LinearLayoutManager) mRecyclerView.getLayoutManager();
+        final EmptyRecyclerView.MyLinearLayoutManager layoutMan = (EmptyRecyclerView.MyLinearLayoutManager) mRecyclerView.getLayoutManager();
         assert layoutMan != null;
         int first_visibile_pos = layoutMan.findFirstCompletelyVisibleItemPosition();
         int last_visible_pos = layoutMan.findLastCompletelyVisibleItemPosition();
diff --git a/app/src/main/java/com/emanuelef/remote_capture/views/AppsListView.java b/app/src/main/java/com/emanuelef/remote_capture/views/AppsListView.java
index b0d65cd3..7869a943 100644
--- a/app/src/main/java/com/emanuelef/remote_capture/views/AppsListView.java
+++ b/app/src/main/java/com/emanuelef/remote_capture/views/AppsListView.java
@@ -27,7 +27,6 @@ import android.widget.Filterable;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.widget.SearchView;
-import androidx.recyclerview.widget.LinearLayoutManager;
 
 import com.emanuelef.remote_capture.adapters.AppsAdapter;
 import com.emanuelef.remote_capture.model.AppDescriptor;
@@ -57,7 +56,7 @@ public class AppsListView extends EmptyRecyclerView implements SearchView.OnQuer
 
     private void initialize(Context context) {
         mAllApps = null;
-        setLayoutManager(new LinearLayoutManager(context));
+        setLayoutManager(new MyLinearLayoutManager(context));
         setHasFixedSize(true);
     }
 
diff --git a/app/src/main/java/com/emanuelef/remote_capture/views/EmptyRecyclerView.java b/app/src/main/java/com/emanuelef/remote_capture/views/EmptyRecyclerView.java
index 2d79074c..30ceb906 100644
--- a/app/src/main/java/com/emanuelef/remote_capture/views/EmptyRecyclerView.java
+++ b/app/src/main/java/com/emanuelef/remote_capture/views/EmptyRecyclerView.java
@@ -24,6 +24,7 @@ import android.util.AttributeSet;
 import android.view.View;
 
 import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.SimpleItemAnimator;
 
@@ -31,6 +32,25 @@ import androidx.recyclerview.widget.SimpleItemAnimator;
 public class EmptyRecyclerView extends RecyclerView {
     private View mEmptyView;
 
+    /* Workaround for crash "java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position 0(offset:-1)".
+     * See https://stackoverflow.com/questions/30220771/recyclerview-inconsistency-detected-invalid-item-position .
+     * It can be reproduced by setting CaptureService.CONNECTIONS_LOG_SIZE = 4 and triggering a rollover right after inserting
+     * item 3 in the register. It may take several tries to reproduce.
+     * Possibly related issues:
+     *  - https://issuetracker.google.com/issues?q=componentid:192731%2B%20IndexOutOfBoundsException%20Invalid%20item%20position
+     * Another way to fix the issue is to disable the item animations via setItemAnimator(null).
+     */
+    public static class MyLinearLayoutManager extends LinearLayoutManager {
+        public MyLinearLayoutManager(Context context) {
+            super(context);
+        }
+
+        @Override
+        public boolean supportsPredictiveItemAnimations() {
+            return false;
+        }
+    }
+
     public EmptyRecyclerView(Context context) {
         super(context);
         init();