maheshgiri · October 9, 2017 17:03 · Oct 17, 2015
diff --git a/GridLayoutManager.java b/GridLayoutManager.java
@@ -0,0 +1,117 @@
+import android.content.Context;
+import android.support.v7.widget.RecyclerView;
+import android.util.AttributeSet;
+import android.view.View;
+
+/**
+ * {@link GridLayoutManager} extension which introduces workaround for focus finding bug when
+ * navigating with dpad.
+ *
+ * @see <a href="http://stackoverflow.com/questions/31596801/recyclerview-focus-scrolling">http://stackoverflow.com/questions/31596801/recyclerview-focus-scrolling</a>
+ */
+public class GridLayoutManager extends android.support.v7.widget.GridLayoutManager {
+
+    public GridLayoutManager(Context context, AttributeSet attrs, int defStyleAttr,
+            int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    public GridLayoutManager(Context context, int spanCount) {
+        super(context, spanCount);
+    }
+
+    public GridLayoutManager(Context context, int spanCount, int orientation,
+            boolean reverseLayout) {
+        super(context, spanCount, orientation, reverseLayout);
+    }
+
+    @Override
+    public View onFocusSearchFailed(View focused, int focusDirection,
+            RecyclerView.Recycler recycler, RecyclerView.State state) {
+        // Need to be called in order to layout new row/column
+        View nextFocus = super.onFocusSearchFailed(focused, focusDirection, recycler, state);
+
+        if (nextFocus == null) {
+            return null;
+        }
+
+        int fromPos = getPosition(focused);
+        int nextPos = getNextViewPos(fromPos, focusDirection);
+
+        return findViewByPosition(nextPos);
+    }
+
+    /**
+     * Manually detect next view to focus.
+     *
+     * @param fromPos from what position start to seek.
+     * @param direction in what direction start to seek. Your regular {@code View.FOCUS_*}.
+     * @return adapter position of next view to focus. May be equal to {@code fromPos}.
+     */
+    protected int getNextViewPos(int fromPos, int direction) {
+        int offset = calcOffsetToNextView(direction);
+
+        if (hitBorder(fromPos, offset)) {
+            return fromPos;
+        }
+
+        return fromPos + offset;
+    }
+
+    /**
+     * Calculates position offset.
+     *
+     * @param direction regular {@code View.FOCUS_*}.
+     * @return position offset according to {@code direction}.
+     */
+    protected int calcOffsetToNextView(int direction) {
+        int spanCount = getSpanCount();
+        int orientation = getOrientation();
+
+        if (orientation == VERTICAL) {
+            switch (direction) {
+                case View.FOCUS_DOWN:
+                    return spanCount;
+                case View.FOCUS_UP:
+                    return -spanCount;
+                case View.FOCUS_RIGHT:
+                    return 1;
+                case View.FOCUS_LEFT:
+                    return -1;
+            }
+        } else if (orientation == HORIZONTAL) {
+            switch (direction) {
+                case View.FOCUS_DOWN:
+                    return 1;
+                case View.FOCUS_UP:
+                    return -1;
+                case View.FOCUS_RIGHT:
+                    return spanCount;
+                case View.FOCUS_LEFT:
+                    return -spanCount;
+            }
+        }
+
+        return 0;
+    }
+
+    /**
+     * Checks if we hit borders.
+     *
+     * @param from from what position.
+     * @param offset offset to new position.
+     * @return {@code true} if we hit border.
+     */
+    private boolean hitBorder(int from, int offset) {
+        int spanCount = getSpanCount();
+
+        if (Math.abs(offset) == 1) {
+            int spanIndex = from % spanCount;
+            int newSpanIndex = spanIndex + offset;
+            return newSpanIndex < 0 || newSpanIndex >= spanCount;
+        } else {
+            int newPos = from + offset;
+            return newPos < 0 && newPos >= spanCount;
+        }
+    }
+}
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