Cardslib: use viewholder in the different card layouts

Again a tiny optimization which helps listviews to prevent
expensive calls for fiendViewById.

Add viewholder to CardHeader, CardExpanded and Card.

Change-Id: Ie363208c836e055e95ec4f58a351496ecbfa8972

3 files changed, 57 insertions, 14 deletions

diff --git a/src/com/android/cards/internal/Card.java b/src/com/android/cards/internal/Card.java
index 1292278..9386599 100644
--- a/src/com/android/cards/internal/Card.java
+++ b/src/com/android/cards/internal/Card.java
@@ -258,6 +258,7 @@ public class Card extends BaseCard {
      * This method sets values to header elements and customizes view.
      * <p/>
      * Override this method to set your elements inside InnerView.
+     * If you use listviews it is recommend to user a Viewholder like here.
      *
      * @param parent parent view (Inner Frame)
      * @param view   Inner View
@@ -267,12 +268,25 @@ public class Card extends BaseCard {
 
         //Add simple title to header
         if (view != null) {
-            TextView mTitleView = (TextView) view.findViewById(R.id.card_main_inner_simple_title);
-            if (mTitleView != null)
-                mTitleView.setText(mTitle);
+            ViewHolder holder;
+            holder = (ViewHolder) view.getTag();
+
+            if (holder == null) {
+                holder = new ViewHolder();
+                holder.titleView =
+                        (TextView) view.findViewById(R.id.card_main_inner_simple_title);
+                view.setTag(holder);
+            }
+            if (holder.titleView != null) {
+                holder.titleView.setText(mTitle);
+            }
         }
+
     }
 
+    static class ViewHolder {
+        TextView titleView;
+    }
 
     // -------------------------------------------------------------
     // CardThumbnail
diff --git a/src/com/android/cards/internal/CardExpand.java b/src/com/android/cards/internal/CardExpand.java
index 718be7a..e0d34fe 100644
--- a/src/com/android/cards/internal/CardExpand.java
+++ b/src/com/android/cards/internal/CardExpand.java
@@ -145,6 +145,7 @@ public class CardExpand extends BaseCard {
      * This method sets values to expand elements and customizes view.
      *
      * Override this method to customize your Expand View
+     * If you use listviews it is recommend to user a Viewholder like here.
      *
      * @param parent  Expand external Layout
      * @param view  inner-expand view
@@ -152,12 +153,25 @@ public class CardExpand extends BaseCard {
     @Override
     public void setupInnerViewElements(ViewGroup parent, View view) {
 
-        //Add simple title to expand area
-        if (view!=null){
-            TextView mTitleView=(TextView) view.findViewById(R.id.card_expand_inner_simple_title);
-            if (mTitleView!=null)
-                mTitleView.setText(mTitle);
+        // Add simple title to expand area
+        if (view != null) {
+            ViewHolder holder;
+            holder = (ViewHolder) view.getTag();
+
+            if (holder == null) {
+                holder = new ViewHolder();
+                holder.titleView =
+                        (TextView) view.findViewById(R.id.card_expand_inner_simple_title);
+                view.setTag(holder);
+            }
+            if (holder.titleView != null) {
+                holder.titleView.setText(mTitle);
+            }
         }
+
     }
 
+    static class ViewHolder {
+        TextView titleView;
+    }
 }
diff --git a/src/com/android/cards/internal/CardHeader.java b/src/com/android/cards/internal/CardHeader.java
index 0507d1b..49b8bed 100644
--- a/src/com/android/cards/internal/CardHeader.java
+++ b/src/com/android/cards/internal/CardHeader.java
@@ -367,22 +367,37 @@ public class CardHeader extends BaseCard {
      * This method sets values to header elements and customizes view.
      *
      * Override this method to set your elements inside InnerView.
+     * If you use listviews it is recommend to user a Viewholder like here.
      *
      * @param parent  parent view (Inner Frame)
      * @param view   Inner View
      */
     @Override
-    public void setupInnerViewElements(ViewGroup parent,View view){
+    public void setupInnerViewElements(ViewGroup parent, View view) {
+
+        // Add simple title to header
+        if (view != null) {
+            ViewHolder holder;
+            holder = (ViewHolder) view.getTag();
+
+            if (holder == null) {
+                holder = new ViewHolder();
+                holder.titleView =
+                        (TextView) view.findViewById(R.id.card_header_inner_simple_title);
+                view.setTag(holder);
+            }
 
-        //Add simple title to header
-        if (view!=null){
-            TextView mTitleView=(TextView) view.findViewById(R.id.card_header_inner_simple_title);
-            if (mTitleView!=null)
-                mTitleView.setText(mTitle);
+            if (holder.titleView != null) {
+                holder.titleView.setText(mTitle);
+            }
         }
 
     }
 
+    static class ViewHolder {
+        TextView titleView;
+    }
+
     // -------------------------------------------------------------
     //  Getters and Setters
     // -------------------------------------------------------------