Added OnClickListener for header view

res/layout/feeditemlist_header.xml

@@ -4,15 +4,26 @@
     android:layout_height="match_parent"
     android:background="?attr/borderless_button" >
 
+    <ImageView
+        android:id="@+id/imgvHeaderArrow"
+        android:layout_width="@dimen/thumbnail_length"
+        android:layout_height="match_parent"
+        android:layout_alignParentLeft="true"
+        android:layout_centerVertical="true"
+        android:padding="12dp"
+        android:scaleType="fitEnd"
+        android:src="?attr/navigation_expand" />
+
     <TextView
         android:id="@+id/txtvHeaderTitle"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_centerVertical="true"
         android:layout_marginBottom="24dp"
-        android:layout_marginLeft="16dp"
+        android:layout_marginLeft="8dp"
         android:layout_marginRight="16dp"
         android:layout_marginTop="24dp"
+        android:layout_toRightOf="@id/imgvHeaderArrow"
         android:textColor="@color/bright_blue"
         android:textSize="@dimen/text_size_large"
         android:textStyle="bold" />

res/values/attrs.xml

@@ -18,6 +18,7 @@
     <attr name="navigation_accept" format="reference" />
     <attr name="navigation_cancel" format="reference" />
     <attr name="navigation_expand" format="reference" />
+    <attr name="navigation_collapse" format="reference" />
     <attr name="navigation_refresh" format="reference" />
     <attr name="navigation_up" format="reference" />
     <attr name="social_share" format="reference" />

res/values/styles.xml

@@ -20,6 +20,7 @@
         <item name="attr/navigation_accept">@drawable/navigation_accept</item>
         <item name="attr/navigation_cancel">@drawable/navigation_cancel</item>
         <item name="attr/navigation_expand">@drawable/navigation_expand</item>
+        <item name="attr/navigation_collapse">@drawable/navigation_collapse</item>
         <item name="attr/navigation_refresh">@drawable/navigation_refresh</item>
         <item name="attr/navigation_up">@drawable/navigation_up</item>
         <item name="attr/social_share">@drawable/social_share</item>
@@ -55,6 +56,7 @@
         <item name="attr/navigation_accept">@drawable/navigation_accept_dark</item>
         <item name="attr/navigation_cancel">@drawable/navigation_cancel_dark</item>
         <item name="attr/navigation_expand">@drawable/navigation_expand_dark</item>
+        <item name="attr/navigation_collapse">@drawable/navigation_collapse_dark</item>
         <item name="attr/navigation_refresh">@drawable/navigation_refresh_dark</item>
         <item name="attr/navigation_up">@drawable/navigation_up_dark</item>
         <item name="attr/social_share">@drawable/social_share_dark</item>

src/de/danoeh/antennapod/adapter/OnItemlistHeaderClicked.java

@@ -0,0 +1,55 @@
+package de.danoeh.antennapod.adapter;
+
+import de.danoeh.antennapod.R;
+import android.content.res.TypedArray;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.widget.ImageView;
+
+/**
+ * OnClickListener for the itemlist headers of feeditem lists. This class takes
+ * care of changing the appearance of the arrow on the left side of the header
+ * view. An instance of this class should be set as the OnClickListener of the
+ * header view.
+ */
+public class OnItemlistHeaderClicked implements OnClickListener {
+	private ImageView arrow;
+	private View header;
+
+	private boolean isExpanded;
+
+	/**
+	 * Constructor
+	 * 
+	 * @param header
+	 *            Reference to the header View of the itemlist.
+	 * @param isExpanded
+	 *            true if the itemlist is currently expanded.
+	 * */
+	public OnItemlistHeaderClicked(View header, boolean isExpanded) {
+		if (header == null)
+			throw new IllegalArgumentException("Header view must not be null");
+		this.header = header;
+		arrow = (ImageView) header.findViewById(R.id.imgvHeaderArrow);
+		this.isExpanded = isExpanded;
+		refreshArrowState();
+	}
+
+	private void refreshArrowState() {
+		TypedArray typeDrawables = header.getContext().obtainStyledAttributes(
+				new int[] { R.attr.navigation_collapse,
+						R.attr.navigation_expand });
+		if (isExpanded) {
+			arrow.setImageDrawable(typeDrawables.getDrawable(0));
+		} else {
+			arrow.setImageDrawable(typeDrawables.getDrawable(1));
+		}
+	}
+
+	@Override
+	public void onClick(View v) {
+		isExpanded = !isExpanded;
+		refreshArrowState();
+	}
+
+}