fix: preferences fragment is recreated after configuration change

app/src/main/java/com/itsaky/androidide/activities/PreferencesActivity.java

@@ -20,6 +20,7 @@ package com.itsaky.androidide.activities;
 import android.os.Bundle;
 import android.view.View;
 
+import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
 
 import com.itsaky.androidide.R;
@@ -46,7 +47,11 @@ public class PreferencesActivity extends IDEActivity {
     getSupportActionBar().setDisplayHomeAsUpEnabled(true);
 
     binding.toolbar.setNavigationOnClickListener(v -> onBackPressed());
-
+  
+    if (savedInstanceState != null) {
+      return;
+    }
+    
     final var prefs = IDEPreferences.INSTANCE;
     prefs.getChildren().clear();
     prefs.addPreference(new ConfigurationPreferences());
@@ -55,10 +60,12 @@ public class PreferencesActivity extends IDEActivity {
     final var args = new Bundle();
     args.putParcelableArrayList(
         IDEPreferencesFragment.EXTRA_CHILDREN, new ArrayList<>(prefs.getChildren()));
-    getRootFragment().setArguments(args);
-    loadFragment(getRootFragment());
+    
+    final var root = getRootFragment();
+    root.setArguments(args);
+    loadFragment(root);
   }
-
+  
   @Override
   protected View bindLayout() {
     binding = ActivityPreferencesBinding.inflate(getLayoutInflater());

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

@@ -21,16 +21,11 @@
 
   </com.google.android.material.appbar.AppBarLayout>
 
-  <LinearLayout
+
+  <FrameLayout
+    android:id="@+id/fragmentContainer"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
-
-    <FrameLayout
-      android:id="@+id/fragmentContainer"
-      android:layout_width="match_parent"
-      android:layout_height="match_parent" />
-
-  </LinearLayout>
+    app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior" />
 
 </androidx.coordinatorlayout.widget.CoordinatorLayout>

common/src/main/java/com/itsaky/androidide/app/BaseIDEActivity.kt

@@ -40,9 +40,9 @@ abstract class BaseIDEActivity : AppCompatActivity() {
   open val statusBarColor: Int
     get() = resolveAttr(R.attr.colorSurface)
 
-  fun loadFragment(fragment: Fragment?, id: Int) {
+  fun loadFragment(fragment: Fragment, id: Int) {
     val transaction = supportFragmentManager.beginTransaction()
-    transaction.replace(id, fragment!!)
+    transaction.replace(id, fragment)
     transaction.commit()
   }