Fix crashes on scrolling posts using volume keys.

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/AccountPostsActivity.java

@@ -161,9 +161,13 @@ public class AccountPostsActivity extends BaseActivity implements SortTypeSelect
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (mFragment != null) {
             return ((FragmentCommunicator) mFragment).handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
 
+        return super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/AccountSavedThingActivity.java

@@ -154,9 +154,13 @@ public class AccountSavedThingActivity extends BaseActivity {
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (sectionsPagerAdapter != null) {
             return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
 
+        return super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/FilteredThingActivity.java

@@ -180,9 +180,13 @@ public class FilteredThingActivity extends BaseActivity implements SortTypeSelec
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (mFragment != null) {
             return ((FragmentCommunicator) mFragment).handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
 
+        return super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/MainActivity.java

@@ -942,9 +942,13 @@ public class MainActivity extends BaseActivity implements SortTypeSelectionCallb
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (sectionsPagerAdapter != null) {
             return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
 
+        return super.onKeyDown(keyCode, event);
+    }
+
     @Override
     protected void onSaveInstanceState(@NonNull Bundle outState) {
         super.onSaveInstanceState(outState);

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/SearchResultActivity.java

@@ -173,8 +173,11 @@ public class SearchResultActivity extends BaseActivity implements SortTypeSelect
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (sectionsPagerAdapter != null) {
             return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
+        return super.onKeyDown(keyCode, event);
+    }
 
     @Override
     public SharedPreferences getSharedPreferences() {

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewPostDetailActivity.java

@@ -1564,10 +1564,14 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
     }
 
     public void lockSwipeRightToGoBack() {
+        if (mSlidrInterface != null) {
             mSlidrInterface.lock();
         }
+    }
 
     public void unlockSwipeRightToGoBack() {
+        if (mSlidrInterface != null) {
             mSlidrInterface.unlock();
         }
+    }
 }

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewSubredditDetailActivity.java

@@ -336,9 +336,13 @@ public class ViewSubredditDetailActivity extends BaseActivity implements SortTyp
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (mFragment != null) {
             return ((FragmentCommunicator)(mFragment)).handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
 
+        return super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;
@@ -645,8 +649,10 @@ public class ViewSubredditDetailActivity extends BaseActivity implements SortTyp
             mSharedPreferences.edit().putString(SharedPreferencesUtils.SORT_TIME_SUBREDDIT_POST, sortType.getTime().name()).apply();
         }
 
+        if (mFragment != null) {
             ((PostFragment) mFragment).changeSortType(sortType);
         }
+    }
 
     @Override
     public void sortTypeSelected(String sortType) {

app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewUserDetailActivity.java

@@ -399,9 +399,13 @@ public class ViewUserDetailActivity extends BaseActivity implements SortTypeSele
 
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (sectionsPagerAdapter != null) {
             return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
         }
 
+        return super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;