Merge pull request #256 from dmccartney/master

added OnStickyHeaderChangedListener
emilsjolander · Feb 9, 2014 · 12adcdd · 12adcdd
2 parents fdcb779 + 9c28bcf
commit 12adcdd
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Showing 3 changed files with 44 additions and 3 deletions.
diff --git a/README.md b/README.md
@@ -184,6 +184,15 @@ public interface OnStickyHeaderOffsetChangedListener {
 }
 ```
 
+A `OnStickyHeaderChangedListener` listens for changes to the header.  This enables UI elements elsewhere to react to the current header (e.g. if each header is a date, then the rest of the UI can update when you scroll to a new date).
+```java
+public void setOnStickyHeaderChangedListener(OnStickyHeaderChangedListener listener);
+
+public interface OnStickyHeaderChangedListener {
+    void onStickyHeaderChanged(StickyListHeadersListView l, View header, int itemPosition, long headerId);
+}
+```
+
 Here are two methods added to the API for inspecting the children of the underlying `ListView`. I could not override the normal `getChildAt()` and `getChildCount()` methods as that would mess up the underlying measurement system of the `FrameLayout` wrapping the `ListView`.
 ```java
 public View getListChildAt(int index);

diff --git a/library/src/se/emilsjolander/stickylistheaders/StickyListHeadersListView.java b/library/src/se/emilsjolander/stickylistheaders/StickyListHeadersListView.java
@@ -55,6 +55,22 @@ public interface OnStickyHeaderOffsetChangedListener {
         public void onStickyHeaderOffsetChanged(StickyListHeadersListView l, View header, int offset);
     }
 
+    /**
+     * Notifies the listener when the sticky header has been updated
+     */
+    public interface OnStickyHeaderChangedListener {
+        /**
+         * @param l             The view parent
+         * @param header        The new sticky header view.
+         * @param itemPosition  The position of the item within the adapter's data set of
+         *                      the item whose header is now sticky.
+         * @param headerId      The id of the new sticky header.
+         */
+        public void onStickyHeaderChanged(StickyListHeadersListView l, View header,
+                                          int itemPosition, long headerId);
+
+    }
+
     /* --- Children --- */
     private WrapperViewList mList;
     private View mHeader;
@@ -81,6 +97,7 @@ public interface OnStickyHeaderOffsetChangedListener {
     /* --- Other --- */
     private OnHeaderClickListener mOnHeaderClickListener;
     private OnStickyHeaderOffsetChangedListener mOnStickyHeaderOffsetChangedListener;
+    private OnStickyHeaderChangedListener mOnStickyHeaderChangedListener;
     private AdapterWrapperDataSetObserver mDataSetObserver;
     private Drawable mDivider;
     private int mDividerHeight;
@@ -310,10 +327,12 @@ private void updateHeader(int firstVisiblePosition) {
                     }
                     swapHeader(header);
                 }
-
                 ensureHeaderHasCorrectLayoutParams(mHeader);
                 measureHeader(mHeader);
-
+                if(mOnStickyHeaderChangedListener != null) {
+                    mOnStickyHeaderChangedListener.onStickyHeaderChanged(this,
+                            mHeader, firstVisiblePosition, mHeaderId);
+                }
                 // Reset mHeaderOffset to null ensuring
                 // that it will be set on the header and
                 // not skipped for performance reasons.
@@ -572,6 +591,10 @@ public void setOnStickyHeaderOffsetChangedListener(OnStickyHeaderOffsetChangedLi
         mOnStickyHeaderOffsetChangedListener = listener;
     }
 
+    public void setOnStickyHeaderChangedListener(OnStickyHeaderChangedListener listener) {
+        mOnStickyHeaderChangedListener = listener;
+    }
+
     public View getListChildAt(int index) {
         return mList.getChildAt(index);
     }

diff --git a/sample/src/se/emilsjolander/stickylistheaders/TestActivity.java b/sample/src/se/emilsjolander/stickylistheaders/TestActivity.java
@@ -16,7 +16,8 @@
  */
 public class TestActivity extends ActionBarActivity implements
         AdapterView.OnItemClickListener, StickyListHeadersListView.OnHeaderClickListener,
-        StickyListHeadersListView.OnStickyHeaderOffsetChangedListener {
+        StickyListHeadersListView.OnStickyHeaderOffsetChangedListener,
+        StickyListHeadersListView.OnStickyHeaderChangedListener {
 
     private TestBaseAdapter mAdapter;
     private DrawerLayout mDrawerLayout;
@@ -44,6 +45,7 @@ public void onCreate(Bundle savedInstanceState) {
         stickyList = (StickyListHeadersListView) findViewById(R.id.list);
         stickyList.setOnItemClickListener(this);
         stickyList.setOnHeaderClickListener(this);
+        stickyList.setOnStickyHeaderChangedListener(this);
         stickyList.setOnStickyHeaderOffsetChangedListener(this);
         stickyList.addHeaderView(getLayoutInflater().inflate(R.layout.list_header, null));
         stickyList.addFooterView(getLayoutInflater().inflate(R.layout.list_footer, null));
@@ -166,4 +168,11 @@ public void onStickyHeaderOffsetChanged(StickyListHeadersListView l, View header
             header.setAlpha(1 - (offset / (float) header.getMeasuredHeight()));
         }
     }
+
+    @Override
+    public void onStickyHeaderChanged(StickyListHeadersListView l, View header,
+                                      int itemPosition, long headerId) {
+        Toast.makeText(this, "Sticky Header Changed to " + headerId,
+                Toast.LENGTH_SHORT).show();
+    }
 }