From a247cc997ea0afb9309f3290db23950fdbdd5467 Mon Sep 17 00:00:00 2001
From: Thomas <tschneider.ac@gmail.com>
Date: Tue, 8 Dec 2020 08:55:26 +0100
Subject: [PATCH] Improve app remember position by using first visible item.

---
 .../exodusprivacy/MainActivity.java           |  9 +-------
 .../adapters/ApplicationListAdapter.java      |  4 ++--
 .../fragments/AppListFragment.java            | 23 ++++++++++++++++---
 .../exodusprivacy/fragments/HomeFragment.java |  9 +-------
 4 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/MainActivity.java b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/MainActivity.java
index d0e32a1..8d811be 100644
--- a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/MainActivity.java
+++ b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/MainActivity.java
@@ -61,7 +61,6 @@ public class MainActivity extends AppCompatActivity {
     private String packageName;
     private MainBinding binding;
     private ApplicationListAdapter.OnAppClickListener onAppClickListener;
-    private int appPosition;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -72,7 +71,6 @@ public class MainActivity extends AppCompatActivity {
             getSupportActionBar().setTitle(R.string.app_title);
         }
         fragments = new ArrayList<>();
-        appPosition = 0;
         NetworkListener networkListener = new NetworkListener() {
             @Override
             public void onSuccess() {
@@ -121,11 +119,10 @@ public class MainActivity extends AppCompatActivity {
                     .commit();
         };
 
-        onAppClickListener = (vm, position) -> {
+        onAppClickListener = (vm) -> {
             try {
                 PackageManager pm = getPackageManager();
                 PackageInfo packageInfo = pm.getPackageInfo(vm.packageName, PackageManager.GET_PERMISSIONS);
-                appPosition = position;
                 ReportFragment report = ReportFragment.newInstance(pm, vm, packageInfo, onTrackerClickListener);
                 fragments.add(report);
                 FragmentManager manager = getSupportFragmentManager();
@@ -168,10 +165,6 @@ public class MainActivity extends AppCompatActivity {
         else {
             getSupportFragmentManager().popBackStack();
             fragments.remove(fragments.size() - 1);
-            Updatable updatable = fragments.get(fragments.size() - 1);
-            if (updatable instanceof HomeFragment) {
-                ((HomeFragment) updatable).scrollTo(appPosition);
-            }
         }
     }
 
diff --git a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/adapters/ApplicationListAdapter.java b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/adapters/ApplicationListAdapter.java
index 8ef1073..8e43271 100644
--- a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/adapters/ApplicationListAdapter.java
+++ b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/adapters/ApplicationListAdapter.java
@@ -86,7 +86,7 @@ public class ApplicationListAdapter extends RecyclerView.Adapter<RecyclerView.Vi
             final ApplicationListViewHolder holder = (ApplicationListViewHolder) viewHolder;
             ApplicationViewModel vm = applicationViewModels.get(position);
             holder.setViewModel(vm);
-            holder.itemView.setOnClickListener(v -> onAppClickListener.onAppClick(vm, position));
+            holder.itemView.setOnClickListener(v -> onAppClickListener.onAppClick(vm));
         } else //noinspection RedundantSuppression
         {
             //noinspection unused
@@ -145,7 +145,7 @@ public class ApplicationListAdapter extends RecyclerView.Adapter<RecyclerView.Vi
     }
 
     public interface OnAppClickListener {
-        void onAppClick(ApplicationViewModel vm, int position);
+        void onAppClick(ApplicationViewModel vm);
     }
 
     static class ApplicationEmptyViewHolder extends RecyclerView.ViewHolder {
diff --git a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/AppListFragment.java b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/AppListFragment.java
index 8b1b2dc..6a4af55 100644
--- a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/AppListFragment.java
+++ b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/AppListFragment.java
@@ -10,6 +10,7 @@ import androidx.annotation.NonNull;
 import androidx.databinding.DataBindingUtil;
 import androidx.fragment.app.Fragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
 
 import org.eu.exodus_privacy.exodusprivacy.R;
 import org.eu.exodus_privacy.exodusprivacy.adapters.ApplicationListAdapter;
@@ -28,6 +29,7 @@ public class AppListFragment extends Fragment {
     private Type filterType = Type.NAME;
     private Object filterObject = "";
     private boolean scrollbarEnabled = true;
+    private static int firstVisiblePosition = 0;
 
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
@@ -38,8 +40,21 @@ public class AppListFragment extends Fragment {
             applications = new ArrayList<>();
         Context context = applistBinding.getRoot().getContext();
         //configure list
-        applistBinding.appList.setLayoutManager(new LinearLayoutManager(context));
+        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context);
+        applistBinding.appList.setLayoutManager(linearLayoutManager);
         applistBinding.appList.setVerticalScrollBarEnabled(scrollbarEnabled);
+        applistBinding.appList.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
+                super.onScrollStateChanged(recyclerView, newState);
+            }
+
+            @Override
+            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
+                super.onScrolled(recyclerView, dx, dy);
+                firstVisiblePosition = linearLayoutManager.findFirstCompletelyVisibleItemPosition();
+            }
+        });
         adapter = new ApplicationListAdapter(onAppClickListener);
         adapter.displayAppList(applications);
         adapter.filter(filterType, filterObject);
@@ -54,6 +69,8 @@ public class AppListFragment extends Fragment {
     public void setApplications(List<ApplicationViewModel> applicationList) {
         applications = applicationList;
         if (adapter != null)
+
+
             adapter.displayAppList(applications);
     }
 
@@ -93,8 +110,8 @@ public class AppListFragment extends Fragment {
         TRACKER
     }
 
-    public void scrollTo(int position) {
-        applistBinding.appList.scrollToPosition(position);
+    public void scrollTo() {
+        applistBinding.appList.scrollToPosition(firstVisiblePosition);
     }
 
     public enum Order {
diff --git a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/HomeFragment.java b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/HomeFragment.java
index 25abeb7..71c6241 100644
--- a/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/HomeFragment.java
+++ b/app/src/main/java/org/eu/exodus_privacy/exodusprivacy/fragments/HomeFragment.java
@@ -51,7 +51,6 @@ public class HomeFragment extends Fragment implements ComputeAppListTask.Listene
     private int lastResource = 0;
     private int lastProgress = 0;
     private int lastMaxProgress = 0;
-    private int scrollTo = 0;
     private String last_refresh;
 
     @Override
@@ -112,15 +111,9 @@ public class HomeFragment extends Fragment implements ComputeAppListTask.Listene
     @Override
     public void onResume() {
         super.onResume();
-        if (scrollTo > 0) {
-            appListFragment.scrollTo(scrollTo);
-            scrollTo = 0;
-        }
+        appListFragment.scrollTo();
     }
 
-    public void scrollTo(int position) {
-        scrollTo = position;
-    }
 
     @Override
     public void onUpdateComplete() {