Improve fragments consistency while swiping

While swiping in the viewpager, the fragments onResume may haven't been
called yet. This commit initializes the status fragment before onResume and
also fixes the "No Connections" shown just briefly after the connections
fragment is shown

app/src/main/java/com/emanuelef/remote_capture/Utils.java

@@ -50,6 +50,8 @@ import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.os.Environment;
+import android.os.Handler;
+import android.os.Looper;
 import android.provider.MediaStore;
 import android.provider.OpenableColumns;
 import android.text.SpannableString;
@@ -860,4 +862,12 @@ public class Utils {
             showToastLong(ctx, R.string.no_intent_handler_found);
         }
     }
+
+    // Runs the specified runnable now if on the UI thread, otherwise enqueue it to the Handler
+    public static void runOnUi(Runnable r, Handler h) {
+        if(Looper.getMainLooper().getThread() == Thread.currentThread())
+            r.run();
+        else
+            h.post(r);
+    }
 }

app/src/main/java/com/emanuelef/remote_capture/fragments/ConnectionsFragment.java

@@ -111,7 +111,14 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
     public void onResume() {
         super.onResume();
 
+        if((CaptureService.getConnsRegister() != null) || CaptureService.isServiceActive())
+            mEmptyText.setText(R.string.no_connections);
+        else
+            mEmptyText.setText(R.string.capture_not_running);
+
         registerConnsListener();
+        mRecyclerView.setEmptyView(mEmptyText); // after registerConnsListener, when the adapter is populated
+
         refreshMenuIcons();
     }
 
@@ -120,6 +127,7 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
         super.onPause();
 
         unregisterConnsListener();
+        mRecyclerView.setEmptyView(null);
 
         if(mSearchView != null)
             mQueryToApply = mSearchView.getQuery().toString();
@@ -174,10 +182,6 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
         mApps = new AppsResolver(requireContext());
 
         mEmptyText = view.findViewById(R.id.no_connections);
-        if((requireActivity() instanceof MainActivity) &&
-                (((MainActivity) requireActivity()).getState() == AppState.running))
-            mEmptyText.setText(R.string.no_connections);
-
         mActiveFilter = view.findViewById(R.id.active_filter);
         mActiveFilter.setOnCheckedChangeListener((group, checkedId) -> {
             if(mAdapter != null) {
@@ -189,7 +193,6 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
         mAdapter = new ConnectionsAdapter(requireContext(), mApps);
         mRecyclerView.setAdapter(mAdapter);
         listenerSet = false;
-        mRecyclerView.setEmptyView(mEmptyText);
         registerForContextMenu(mRecyclerView);
 
         DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(mRecyclerView.getContext(),
@@ -576,7 +579,8 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
         // Important: must use the provided num_connections rather than accessing the register
         // in order to avoid desyncs
 
-        mHandler.post(() -> {
+        // using runOnUi to populate the adapter as soon as registerConnsListener is called
+        Utils.runOnUi(() -> {
             Log.d(TAG, "New connections size: " + num_connections);
 
             mAdapter.connectionsChanges(num_connections);
@@ -584,7 +588,7 @@ public class ConnectionsFragment extends Fragment implements ConnectionsListener
 
             if(autoScroll)
                 scrollToBottom();
-        });
+        }, mHandler);
     }
 
     @Override

app/src/main/java/com/emanuelef/remote_capture/fragments/StatusFragment.java

@@ -105,11 +105,7 @@ public class StatusFragment extends Fragment implements AppStateListener, AppsLo
     @Override
     public void onResume() {
         super.onResume();
-
-        if((mMenu != null) && (mActivity != null))
-            appStateChanged(mActivity.getState());
-
-        recheckFilterWarning();
+        refreshStatus();
 
         /* Register for stats update */
         mReceiver = new BroadcastReceiver() {
@@ -219,9 +215,7 @@ public class StatusFragment extends Fragment implements AppStateListener, AppsLo
 
         /* Important: call this after all the fields have been initialized */
         mActivity.setAppStateListener(this);
-
-        if((mMenu != null) && (mActivity != null))
-            appStateChanged(mActivity.getState());
+        refreshStatus();
     }
 
     @Override
@@ -231,9 +225,7 @@ public class StatusFragment extends Fragment implements AppStateListener, AppsLo
         mMenu = menu;
         mMenuItemStartBtn = mMenu.findItem(R.id.action_start);
         mMenuSettings = mMenu.findItem(R.id.action_settings);
-
-        if(mActivity != null)
-            appStateChanged(mActivity.getState());
+        refreshStatus();
     }
 
     private void recheckFilterWarning() {
@@ -395,6 +387,12 @@ private void refreshPcapDumpInfo() {
         }
     }
 
+    private void refreshStatus() {
+        if(mActivity != null)
+            appStateChanged(mActivity.getState());
+        recheckFilterWarning();
+    }
+
     private void openAppFilterSelector() {
         Dialog dialog = Utils.getAppSelectionDialog(mActivity, new ArrayList<>(), this::setAppFilter);
         dialog.setOnCancelListener(dialog1 -> setAppFilter(null));

app/src/main/res/layout/connections.xml

@@ -36,7 +36,7 @@
             android:layout_marginTop="40dp"
             android:textStyle="italic"
             android:textSize="15sp"
-            android:text="@string/capture_not_started">
+            tools:text="@string/capture_not_started">
         </TextView>
 
         <com.emanuelef.remote_capture.views.EmptyRecyclerView