Use volume keys to navigate posts

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

@@ -5,6 +5,7 @@ import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.os.Build;
 import android.os.Bundle;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -159,6 +160,11 @@ public class AccountPostsActivity extends BaseActivity implements SortTypeSelect
         }
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return ((FragmentCommunicator) mFragment).handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;

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

@@ -5,6 +5,7 @@ import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.os.Build;
 import android.os.Bundle;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -151,6 +152,11 @@ public class AccountSavedThingActivity extends BaseActivity {
         }
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;
@@ -339,6 +345,10 @@ public class AccountSavedThingActivity extends BaseActivity {
             return fragment;
         }
 
+        public boolean handleKeyDown(int keyCode) {
+            return viewPager.getCurrentItem() == 0 && postFragment.handleKeyDown(keyCode);
+        }
+
         public void refresh() {
             if (viewPager.getCurrentItem() == 0) {
                 if (postFragment != null) {

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

@@ -5,6 +5,7 @@ import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.os.Build;
 import android.os.Bundle;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -176,6 +177,11 @@ public class FilteredThingActivity extends BaseActivity implements SortTypeSelec
         postLayoutBottomSheetFragment = new PostLayoutBottomSheetFragment();
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return ((FragmentCommunicator) mFragment).handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;

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

@@ -8,6 +8,7 @@ import android.content.res.Resources;
 import android.os.Build;
 import android.os.Bundle;
 import android.util.TypedValue;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -863,6 +864,11 @@ public class MainActivity extends BaseActivity implements SortTypeSelectionCallb
         }
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     protected void onSaveInstanceState(@NonNull Bundle outState) {
         super.onSaveInstanceState(outState);
@@ -1071,6 +1077,27 @@ public class MainActivity extends BaseActivity implements SortTypeSelectionCallb
             return fragment;
         }
 
+        boolean handleKeyDown(int keyCode) {
+            if (mAccessToken == null) {
+                switch (viewPager.getCurrentItem()) {
+                    case 0:
+                        return popularPostFragment.handleKeyDown(keyCode);
+                    case 1:
+                        return allPostFragment.handleKeyDown(keyCode);
+                }
+            } else {
+                switch (viewPager.getCurrentItem()) {
+                    case 0:
+                        return frontPagePostFragment.handleKeyDown(keyCode);
+                    case 1:
+                        return popularPostFragment.handleKeyDown(keyCode);
+                    case 2:
+                        return allPostFragment.handleKeyDown(keyCode);
+                }
+            }
+            return false;
+        }
+
         boolean startLazyMode() {
             if (mAccessToken == null) {
                 switch (viewPager.getCurrentItem()) {

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

@@ -6,6 +6,7 @@ import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.os.Build;
 import android.os.Bundle;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -170,6 +171,11 @@ public class SearchResultActivity extends BaseActivity implements SortTypeSelect
         }
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;
@@ -368,6 +374,10 @@ public class SearchResultActivity extends BaseActivity implements SortTypeSelect
             return fragment;
         }
 
+        public boolean handleKeyDown(int keyCode) {
+            return viewPager.getCurrentItem() == 0 && postFragment.handleKeyDown(keyCode);
+        }
+
         void changeSortType(SortType sortType) {
             mSharedPreferences.edit().putString(SharedPreferencesUtils.SORT_TYPE_SEARCH_POST, sortType.getType().name()).apply();
             if(sortType.getTime() != null) {

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

@@ -7,6 +7,7 @@ import android.content.res.Resources;
 import android.os.AsyncTask;
 import android.os.Build;
 import android.os.Bundle;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -322,6 +323,11 @@ public class ViewSubredditDetailActivity extends BaseActivity implements SortTyp
         });
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return ((FragmentCommunicator)(mFragment)).handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;

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

@@ -8,6 +8,7 @@ import android.os.AsyncTask;
 import android.os.Build;
 import android.os.Bundle;
 import android.util.TypedValue;
+import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -396,6 +397,11 @@ public class ViewUserDetailActivity extends BaseActivity implements SortTypeSele
         postLayoutBottomSheetFragment = new PostLayoutBottomSheetFragment();
     }
 
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        return sectionsPagerAdapter.handleKeyDown(keyCode) || super.onKeyDown(keyCode, event);
+    }
+
     @Override
     public SharedPreferences getSharedPreferences() {
         return mSharedPreferences;
@@ -741,6 +747,10 @@ public class ViewUserDetailActivity extends BaseActivity implements SortTypeSele
             return fragment;
         }
 
+        public boolean handleKeyDown(int keyCode) {
+            return viewPager.getCurrentItem() == 0 && postFragment.handleKeyDown(keyCode);
+        }
+
         public void refresh() {
             if (viewPager.getCurrentItem() == 0) {
                 if (postFragment != null) {

app/src/main/java/ml/docilealligator/infinityforreddit/Fragment/PostFragment.java

@@ -13,6 +13,7 @@ import android.os.Bundle;
 import android.os.CountDownTimer;
 import android.os.Handler;
 import android.util.TypedValue;
+import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -121,6 +122,7 @@ public class PostFragment extends Fragment implements FragmentCommunicator {
     private CountDownTimer resumeLazyModeCountDownTimer;
     private float lazyModeInterval;
     private int postLayout;
+    private boolean mIsSmoothScrolling = false;
 
     public PostFragment() {
         // Required empty public constructor
@@ -137,6 +139,32 @@ public class PostFragment extends Fragment implements FragmentCommunicator {
         }
     }
 
+    private boolean scrollPostsByCount(int count) {
+        mIsSmoothScrolling = true;
+        if (mLinearLayoutManager != null) {
+            int pos = mLinearLayoutManager.findFirstVisibleItemPosition();
+            int targetPosition = pos + count;
+            mLinearLayoutManager.scrollToPositionWithOffset(targetPosition, 0);
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    @Override
+    public boolean handleKeyDown(int keyCode) {
+        boolean volumeKeysNavigatePosts = mSharedPreferences.getBoolean(SharedPreferencesUtils.VOLUME_KEYS_NAVIGATE_POSTS, false);
+        if (volumeKeysNavigatePosts) {
+            switch (keyCode) {
+                case KeyEvent.KEYCODE_VOLUME_UP:
+                    return scrollPostsByCount(-1);
+                case KeyEvent.KEYCODE_VOLUME_DOWN:
+                    return scrollPostsByCount(1);
+            }
+        }
+        return false;
+    }
+
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -160,6 +188,16 @@ public class PostFragment extends Fragment implements FragmentCommunicator {
             }
         };
 
+        mPostRecyclerView.clearOnScrollListeners();
+        mPostRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
+                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+                    mIsSmoothScrolling = false;
+                }
+            }
+        });
+
         window = activity.getWindow();
 
         Resources resources = getResources();
@@ -260,10 +298,12 @@ public class PostFragment extends Fragment implements FragmentCommunicator {
             mPostRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                 @Override
                 public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
-                    if (dy > 0) {
+                    if (!mIsSmoothScrolling) {
-                        ((MainActivity) activity).postScrollDown();
+                        if (dy > 0) {
-                    } else if (dy < 0) {
+                            ((MainActivity) activity).postScrollDown();
-                        ((MainActivity) activity).postScrollUp();
+                        } else if (dy < 0) {
+                            ((MainActivity) activity).postScrollUp();
+                        }
                     }
 
                 }

app/src/main/java/ml/docilealligator/infinityforreddit/FragmentCommunicator.java

@@ -3,6 +3,8 @@ package ml.docilealligator.infinityforreddit;
 public interface FragmentCommunicator {
     void refresh();
 
+    default boolean handleKeyDown(int keyCode) { return false; }
+
     default void changeNSFW(boolean nsfw) {
     }
 

app/src/main/java/ml/docilealligator/infinityforreddit/Utils/SharedPreferencesUtils.java

@@ -59,4 +59,5 @@ public class SharedPreferencesUtils {
     public static final String SHOW_ELAPSED_TIME_KEY = "show_elapsed_time";
     public static final String SWIPE_RIGHT_TO_GO_BACK_FROM_POST_DETAIL = "swipe_to_go_back_from_post_detail";
     public static final String VOLUME_KEYS_NAVIGATE_COMMENTS = "volume_keys_navigate_comments";
+    public static final String VOLUME_KEYS_NAVIGATE_POSTS = "volume_keys_navigate_posts";
 }

app/src/main/res/values/strings.xml

@@ -291,6 +291,7 @@
     <string name="settings_immersive_interface_title">Immersive Interface</string>
     <string name="settings_vote_buttons_on_the_right_title">Vote Buttons on the Right</string>
     <string name="settings_volume_keys_navigate_comments_title">Use Volume Keys to Navigate Comments in Posts</string>
+    <string name="settings_volume_keys_navigate_posts_title">Use Volume Keys to Navigate Posts</string>
     <string name="settings_show_elapsed_time">Show Elpased Time in Posts and Comments</string>
     <string name="swipe_to_go_back_from_post_detail">Swipe Right to Go Back From Comments</string>
     <string name="settings_lazy_mode_interval_title">Lazy Mode Interval</string>

app/src/main/res/xml/main_preferences.xml

@@ -46,6 +46,11 @@
         app:key="volume_keys_navigate_comments"
         app:title="@string/settings_volume_keys_navigate_comments_title" />
 
+    <SwitchPreference
+        app:defaultValue="false"
+        app:key="volume_keys_navigate_posts"
+        app:title="@string/settings_volume_keys_navigate_posts_title" />
+
     <Preference
         app:title="@string/settings_font_size_title"
         app:icon="@drawable/ic_font_size_24dp"