Fixes #3, counting error when there are child views with visibility set to GONE.

Author: nex3z

flowlayout/src/main/java/com/nex3z/flowlayout/FlowLayout.java

@@ -213,10 +213,12 @@ protected void onLayout(boolean changed, int l, int t, int r, int b) {
             int childNum = mChildNumForRow.get(row);
             int rowHeight = mHeightForRow.get(row);
             float spacing = mHorizontalSpacingForRow.get(row);
-            for (int i = 0; i < childNum; i++) {
+            for (int i = 0; i < childNum && childIdx < getChildCount();) {
                 View child = getChildAt(childIdx++);
                 if (child.getVisibility() == GONE) {
                     continue;
+                } else {
+                    i++;
                 }
 
                 LayoutParams childParams = child.getLayoutParams();