add experimental hiding actionbar on scroll

org.fox.ttrss/src/main/java/org/fox/ttrss/ArticleFragment.java

@@ -15,6 +15,7 @@ import android.util.TypedValue;
 import android.view.ContextMenu;
 import android.view.ContextMenu.ContextMenuInfo;
 import android.view.LayoutInflater;
+import android.view.MotionEvent;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewGroup;
@@ -24,12 +25,14 @@ import android.webkit.WebSettings;
 import android.webkit.WebView;
 import android.webkit.WebView.HitTestResult;
 import android.widget.FrameLayout;
+import android.widget.ScrollView;
 import android.widget.TextView;
 
 import com.shamanland.fab.ShowHideOnScroll;
 
 import org.fox.ttrss.types.Article;
 import org.fox.ttrss.types.Attachment;
+import org.fox.ttrss.util.NotifyingScrollView;
 
 import java.net.MalformedURLException;
 import java.net.URI;
@@ -165,9 +168,24 @@ public class ArticleFragment extends Fragment  {
         m_contentView = view.findViewById(R.id.article_scrollview);
         m_customViewContainer = (FrameLayout) view.findViewById(R.id.article_fullscreen_video);
 
-        View scrollView = view.findViewById(R.id.article_scrollview);
+        NotifyingScrollView scrollView = (NotifyingScrollView) view.findViewById(R.id.article_scrollview);
         m_fab = view.findViewById(R.id.article_fab);
 
+        if (scrollView != null && m_activity.isSmallScreen()) {
+            view.findViewById(R.id.article_heading_spacer).setVisibility(View.VISIBLE);
+
+            scrollView.setOnScrollChangedListener(new NotifyingScrollView.OnScrollChangedListener() {
+                @Override
+                public void onScrollChanged(ScrollView who, int l, int t, int oldl, int oldt) {
+                    if (t > 0 && t > oldt) {
+                        m_activity.getSupportActionBar().hide();
+                    } else {
+                        m_activity.getSupportActionBar().show();
+                    }
+                }
+            });
+        }
+
         if (scrollView != null && m_fab != null) {
             if (m_prefs.getBoolean("enable_article_fab", true)) {
                 scrollView.setOnTouchListener(new ShowHideOnScroll(m_fab));

org.fox.ttrss/src/main/java/org/fox/ttrss/HeadlinesActivity.java

@@ -9,9 +9,11 @@ import android.os.Bundle;
 import android.os.Handler;
 import android.preference.PreferenceManager;
 import android.support.v4.app.FragmentTransaction;
+import android.support.v4.view.WindowCompat;
 import android.util.Log;
 import android.view.MenuItem;
 import android.view.View;
+import android.view.Window;
 
 import org.fox.ttrss.types.Article;
 import org.fox.ttrss.types.ArticleList;
@@ -223,6 +225,8 @@ public class HeadlinesActivity extends OnlineActivity implements HeadlinesEventL
 			saveArticleUnread(article);
 		}
 
+        if (!getSupportActionBar().isShowing()) getSupportActionBar().show();
+
 		if (open) {
 			
 			final Article fArticle = article;

org.fox.ttrss/src/main/java/org/fox/ttrss/util/NoChildFocusScrollView.java

@@ -6,7 +6,7 @@ import android.view.View;
 import android.webkit.WebView;
 import android.widget.ScrollView;
 
-public class NoChildFocusScrollView extends ScrollView {
+public class NoChildFocusScrollView extends NotifyingScrollView {
 
 	public NoChildFocusScrollView(Context context) {
 		super(context);

org.fox.ttrss/src/main/java/org/fox/ttrss/util/NotifyingScrollView.java

@@ -0,0 +1,45 @@
+package org.fox.ttrss.util;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.widget.ScrollView;
+
+/**
+ * @author Cyril Mottier
+ */
+public class NotifyingScrollView extends ScrollView {
+
+    /**
+     * @author Cyril Mottier
+     */
+    public interface OnScrollChangedListener {
+        void onScrollChanged(ScrollView who, int l, int t, int oldl, int oldt);
+    }
+
+    private OnScrollChangedListener mOnScrollChangedListener;
+
+    public NotifyingScrollView(Context context) {
+        super(context);
+    }
+
+    public NotifyingScrollView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public NotifyingScrollView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    @Override
+    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
+        super.onScrollChanged(l, t, oldl, oldt);
+        if (mOnScrollChangedListener != null) {
+            mOnScrollChangedListener.onScrollChanged(this, l, t, oldl, oldt);
+        }
+    }
+
+    public void setOnScrollChangedListener(OnScrollChangedListener listener) {
+        mOnScrollChangedListener = listener;
+    }
+
+}

org.fox.ttrss/src/main/res/layout/article_fragment.xml

@@ -22,6 +22,14 @@
             android:layout_height="match_parent"
             android:orientation="vertical" >
 
+            <!-- hack for hiding actionbar on small devices -->
+            <FrameLayout
+                android:id="@+id/article_heading_spacer"
+                android:visibility="gone"
+                android:layout_marginTop="?android:attr/actionBarSize"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"/>
+
             <LinearLayout
                 android:padding="16dp"
                 android:id="@+id/article_header"

org.fox.ttrss/src/main/res/layout/headlines_articles.xml

@@ -1,6 +1,5 @@
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/headlines"
-    android:fitsSystemWindows="true"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent">
 

org.fox.ttrss/src/main/res/values/style.xml

@@ -81,6 +81,8 @@
     </style>
 
     <style name="DarkTheme" parent="Theme.AppCompat">
+        <item name="windowActionBarOverlay">true</item>
+
         <item name="statusBarHintColor">?colorPrimary</item>
         <item name="unreadCounterColor">#909090</item>
         <item name="feedlistTextColor">@android:color/primary_text_dark</item>