Fix commons-app#3203 App Crash when rotating the Peer Review Screen (commons-app#3215)

* Fixing 3203 App crash when rotating the screen

* Add java comments for issue commons-app#3203

* Add if-else curly braces for issue commons-app#3203

Author: DeepaMalani

app/src/main/java/fr/free/nrw/commons/review/ReviewImageFragment.java

@@ -11,7 +11,7 @@
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
-import java.util.List;
+import androidx.annotation.NonNull;
 
 import butterknife.BindView;
 import butterknife.ButterKnife;
@@ -40,6 +40,12 @@ public class ReviewImageFragment extends CommonsDaggerSupportFragment {
     @BindView(R.id.button_no)
     Button noButton;
 
+    // Constant variable used to store user's key name for onSaveInstanceState method
+    private final String SAVED_USER = "saved_user";
+
+    //Variable that stores the value of user
+    private String user;
+
     public void update(int position) {
         this.position = position;
     }
@@ -68,7 +74,7 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
         position = getArguments().getInt("position");
         View layoutView = inflater.inflate(R.layout.fragment_review_image, container,
                 false);
-        ButterKnife.bind(this,layoutView);
+        ButterKnife.bind(this, layoutView);
 
         String question, explanation, yesButtonText, noButtonText;
         switch (position) {
@@ -106,7 +112,16 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
             case THANKS:
                 enableButtons();
                 question = getString(R.string.review_thanks);
-                explanation = getString(R.string.review_thanks_explanation, getReviewActivity().reviewController.firstRevision.getUser());
+
+                //Get existing user name if it is already saved using savedInstanceState else get from reviewController
+                if (savedInstanceState == null) {
+                    user = getReviewActivity().reviewController.firstRevision.getUser();
+                } else {
+                    user = savedInstanceState.getString(SAVED_USER);
+                }
+
+                explanation = getString(R.string.review_thanks_explanation, user);
+
                 yesButtonText = getString(R.string.review_thanks_yes_button_text);
                 noButtonText = getString(R.string.review_thanks_no_button_text);
                 yesButton.setTextColor(Color.parseColor("#228b22"));
@@ -131,6 +146,20 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
         return layoutView;
     }
 
+
+    /**
+     * This method will be called when configuration changes happen
+     *
+     * @param outState
+     */
+    @Override
+    public void onSaveInstanceState(@NonNull Bundle outState) {
+        super.onSaveInstanceState(outState);
+
+        //Save user name when configuration changes happen
+        outState.putString(SAVED_USER, user);
+    }
+
     private ReviewController.ReviewCallback getReviewCallback() {
         return new ReviewController
                 .ReviewCallback() {