fix:click on skip button in Peer Review after orientation change then app is crashed (#4176)

* #fixes-4143
In ReviewActivity overrides two function-> onResume() and onPause()

* Fixed the Bug-#4143

* reformed the codechange

* reformed the codechange

* Add javadoc

* Add javadoc

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

@@ -55,6 +55,11 @@ public class ReviewActivity extends BaseActivity {
     ReviewHelper reviewHelper;
     @Inject
     DeleteHelper deleteHelper;
+    /**
+     * Represent fragment for ReviewImage
+     * Use to call some methods of ReviewImage fragment
+     */
+     private ReviewImageFragment reviewImageFragment;
 
     final String SAVED_MEDIA = "saved_media";
     private Media media;
@@ -98,7 +103,6 @@ public class ReviewActivity extends BaseActivity {
 
         reviewPagerAdapter = new ReviewPagerAdapter(getSupportFragmentManager());
         reviewPager.setAdapter(reviewPagerAdapter);
-        reviewPagerAdapter.getItem(0);
         pagerIndicator.setViewPager(reviewPager);
         progressBar.setVisibility(View.VISIBLE);
 
@@ -113,7 +117,8 @@ public class ReviewActivity extends BaseActivity {
         }
 
         btnSkipImage.setOnClickListener(view -> {
-            reviewPagerAdapter.disableButtons();
+            reviewImageFragment = getInstanceOfReviewImageFragment();
+            reviewImageFragment.disableButtons();
             runRandomizer();
         });
 
@@ -142,7 +147,8 @@ public class ReviewActivity extends BaseActivity {
                 .subscribeOn(Schedulers.io())
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe(media -> {
-                    reviewPagerAdapter.disableButtons();
+                    reviewImageFragment = getInstanceOfReviewImageFragment();
+                    reviewImageFragment.disableButtons();
                     updateImage(media);
                 }));
         return true;
@@ -169,7 +175,8 @@ public class ReviewActivity extends BaseActivity {
                     String caption = String.format(getString(R.string.review_is_uploaded_by), fileName, revision.getUser());
                     imageCaption.setText(caption);
                     progressBar.setVisibility(View.GONE);
-                    reviewPagerAdapter.enableButtons();
+                    reviewImageFragment = getInstanceOfReviewImageFragment();
+                    reviewImageFragment.enableButtons();
                 }));
         reviewPager.setCurrentItem(0);
     }
@@ -226,4 +233,13 @@ public class ReviewActivity extends BaseActivity {
         }
         return super.onOptionsItemSelected(item);
     }
+
+    /**
+     * this function return the instance of  reviewImageFragment
+     */
+    public ReviewImageFragment getInstanceOfReviewImageFragment(){
+        int currentItemOfReviewPager = reviewPager.getCurrentItem();
+        reviewImageFragment = (ReviewImageFragment) reviewPagerAdapter.instantiateItem(reviewPager, currentItemOfReviewPager);
+        return reviewImageFragment;
+    }
 }

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

@@ -2,6 +2,8 @@ package fr.free.nrw.commons.review;
 
 import android.os.Bundle;
 
+import android.view.ViewGroup;
+import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentStatePagerAdapter;
@@ -9,6 +11,13 @@ import androidx.fragment.app.FragmentStatePagerAdapter;
 public class ReviewPagerAdapter extends FragmentStatePagerAdapter {
     private ReviewImageFragment[] reviewImageFragments;
 
+    /**
+     * this function return the instance of ReviewviewPage current item
+     */
+    @Override
+    public Object instantiateItem(@NonNull ViewGroup container, int position) {
+        return super.instantiateItem(container, position);
+    }
 
     ReviewPagerAdapter(FragmentManager fm) {
         super(fm);
@@ -32,25 +41,6 @@ public class ReviewPagerAdapter extends FragmentStatePagerAdapter {
         }
     }
 
-    /**
-     * This function is called when an image has
-     * been loaded to enable the review buttons.
-     */
-    public void enableButtons() {
-        if (reviewImageFragments != null){
-            reviewImageFragments[0].enableButtons();
-        }
-    }
-
-    /**
-     * This function is called when an image is being loaded
-     * to disable the review buttons
-     */
-    public void disableButtons() {
-        if (reviewImageFragments != null){
-            reviewImageFragments[0].disableButtons();
-        }
-    }
 
     @Override
     public Fragment getItem(int position) {