Allow fullscreen reading

app/src/main/java/eu/kanade/mangafeed/ui/activity/ReaderActivity.java

@@ -2,6 +2,7 @@ package eu.kanade.mangafeed.ui.activity;
 
 import android.content.Context;
 import android.content.Intent;
+import android.os.Build;
 import android.os.Bundle;
 import android.view.MotionEvent;
 import android.view.View;
@@ -55,6 +56,9 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
         setContentView(R.layout.activity_reader);
         ButterKnife.bind(this);
 
+        if (prefs.useFullscreenSet())
+            enableFullScreen();
+
         viewer = getViewer();
 
         enableHardwareAcceleration();
@@ -75,10 +79,22 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
         viewer.setSelectedPage(pageIndex);
     }
 
-    public void hideStatusBar() {
-        View decorView = getWindow().getDecorView();
-        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
-        decorView.setSystemUiVisibility(uiOptions);
+    public void enableFullScreen() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+            getWindow().getDecorView().setSystemUiVisibility(
+                    View.SYSTEM_UI_FLAG_LOW_PROFILE
+                            | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
+                            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
+                            | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
+                            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
+                            | View.SYSTEM_UI_FLAG_FULLSCREEN
+                            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+            );
+        } else {
+            getWindow().getDecorView().setSystemUiVisibility(
+                    View.SYSTEM_UI_FLAG_LOW_PROFILE
+            );
+        }
     }
 
     public void enableHardwareAcceleration() {