A bit of refactoring

app/src/main/java/com/github/yeriomin/yalpstore/AppListActivity.java

@@ -25,11 +25,8 @@ abstract public class AppListActivity extends YalpStoreActivity {
     protected List<Map<String, Object>> data = new ArrayList<>();
     protected Map<String, App> apps = new HashMap<>();
 
-    protected ListAdapter listAdapter;
     protected ListView listView;
 
-    private boolean finishedStart = false;
-
     abstract protected void loadApps();
 
     @Override
@@ -37,7 +34,6 @@ abstract public class AppListActivity extends YalpStoreActivity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.applist_activity_layout);
 
-        setListAdapter(getSimpleListAdapter());
         getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
             @Override
             public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
@@ -59,10 +55,9 @@ abstract public class AppListActivity extends YalpStoreActivity {
         if (emptyView != null) {
             listView.setEmptyView(emptyView);
         }
-        if (finishedStart) {
-            setListAdapter(listAdapter);
+        if (null == listView.getAdapter()) {
+            listView.setAdapter(getSimpleListAdapter());
         }
-        finishedStart = true;
     }
 
     protected Map<String, Object> formatApp(App app) {
@@ -77,13 +72,13 @@ abstract public class AppListActivity extends YalpStoreActivity {
             data.add(this.formatApp(app));
             apps.put(app.getPackageName(), app);
         }
-        ((SimpleAdapter) getListAdapter()).notifyDataSetChanged();
+        ((SimpleAdapter) getListView().getAdapter()).notifyDataSetChanged();
     }
 
     protected void clearApps() {
         apps.clear();
         data.clear();
-        ((SimpleAdapter) getListAdapter()).notifyDataSetChanged();
+        ((SimpleAdapter) getListView().getAdapter()).notifyDataSetChanged();
     }
 
     private SimpleAdapter getSimpleListAdapter() {
@@ -102,18 +97,7 @@ abstract public class AppListActivity extends YalpStoreActivity {
         return adapter;
     }
 
-    public void setListAdapter(ListAdapter adapter) {
-        synchronized (this) {
-            listAdapter = adapter;
-            listView.setAdapter(adapter);
-        }
-    }
-
     public ListView getListView() {
         return listView;
     }
-
-    public ListAdapter getListAdapter() {
-        return listAdapter;
-    }
 }

app/src/main/java/com/github/yeriomin/yalpstore/CategoryAppsActivity.java

@@ -32,7 +32,7 @@ public class CategoryAppsActivity extends EndlessScrollActivity {
             categoryId = newCategoryId;
             setTitle(new CategoryManager(this).getCategoryName(categoryId));
             loadApps();
-            ((SimpleAdapter) getListAdapter()).notifyDataSetChanged();
+            ((SimpleAdapter) getListView().getAdapter()).notifyDataSetChanged();
         }
     }
 

app/src/main/java/com/github/yeriomin/yalpstore/DownloadOrInstallFragment.java

@@ -80,10 +80,14 @@ public class DownloadOrInstallFragment extends DetailsFragment {
     }
 
     public void unregisterReceivers() {
-        activity.unregisterReceiver(downloadReceiver);
-        downloadReceiver = null;
-        activity.unregisterReceiver(installReceiver);
-        installReceiver = null;
+        if (null != downloadReceiver) {
+            activity.unregisterReceiver(downloadReceiver);
+            downloadReceiver = null;
+        }
+        if (null != installReceiver) {
+            activity.unregisterReceiver(installReceiver);
+            installReceiver = null;
+        }
     }
 
     public void registerReceivers() {

app/src/main/java/com/github/yeriomin/yalpstore/SearchResultActivity.java

@@ -65,7 +65,7 @@ public class SearchResultActivity extends EndlessScrollActivity {
         };
         task.setCategoryManager(new CategoryManager(this));
         prepareTask(task).execute(query, categoryId);
-        ((SimpleAdapter) getListAdapter()).notifyDataSetChanged();
+        ((SimpleAdapter) getListView().getAdapter()).notifyDataSetChanged();
     }
 
     private String getQuery(Intent intent) {

app/src/main/java/com/github/yeriomin/yalpstore/UpdatableAppsTask.java

@@ -93,8 +93,6 @@ class UpdatableAppsTask extends GoogleApiAsyncTask {
             installedApp.setOfferType(appFromMarket.getOfferType());
             installedApp.setPermissions(appFromMarket.getPermissions());
             if (installedApp.getVersionCode() < appFromMarket.getVersionCode()) {
-                installedApp.setUpdated(appFromMarket.getUpdated());
-                installedApp.setVersionCode(appFromMarket.getVersionCode());
                 appFromMarket.setDisplayName(installedApp.getDisplayName());
                 appFromMarket.setIcon(installedApp.getIcon());
                 appFromMarket.setInstalled(true);