Add onLayout callback prop

README.md

@@ -105,6 +105,7 @@ import { SuperGridSectionList } from 'react-native-super-grid';
 | style | [FlatList](https://facebook.github.io/react-native/docs/flatlist.html) styles (Object) |  | Styles for the container. Styles for an item should be applied inside ```renderItem```. |
 | staticDimension | Number | undefined | Specifies a static width or height for the GridView container. If your container dimension is known or can be calculated at runtime (via ```Dimensions.get('window')```, for example), passing this prop will force the grid container to that dimension size and avoid the reflow associated with dynamically calculating it|
 | horizontal | boolean | false | If true, the grid will be scrolling horizontally **(this prop doesn't affect the SuperGridSectionList, which only scrolls vertically)** |
+| onLayout | Function |  | Optional callback ran by the internal `FlatList` or `SectionList`'s `onLayout` function, thus invoked on mount and layout changes. |
 
 Note: If you want your item to fill the height when using a horizontal grid, you should give it a height of '100%'
 

SuperGridSectionList.js

@@ -27,7 +27,7 @@ class SuperGridSectionList extends Component {
 
   
   onLayout(e) {
-    const { staticDimension } = this.props;
+    const { staticDimension, onLayout } = this.props;
     if (!staticDimension) {
       const { width, height } = e.nativeEvent.layout || {};
 
@@ -35,6 +35,10 @@ class SuperGridSectionList extends Component {
         ...this.getDimensions(width),
       });
     }
+    // run onLayout callback if provided
+    if (onLayout) {
+      onLayout(e);
+    }
   }
 
   getDimensions(lvDimension, itemDim) {
@@ -102,7 +106,7 @@ class SuperGridSectionList extends Component {
   }
 
   render() {
-    const { sections, style, spacing, fixed, itemDimension, renderItem, renderSectionHeader, ...props } = this.props;
+    const { sections, style, spacing, fixed, itemDimension, renderItem, renderSectionHeader, onLayout, ...props } = this.props;
     const { itemsPerRow } = this.state;
 
     //Deep copy, so that re-renders and chunkArray functions don't affect the actual items object
@@ -149,6 +153,7 @@ SuperGridSectionList.propTypes = {
   spacing: PropTypes.number,
   style: ViewPropTypes.style,
   staticDimension: PropTypes.number,
+  onLayout: PropTypes.func,
 };
 
 SuperGridSectionList.defaultProps = {

index.d.ts

@@ -47,6 +47,12 @@ export interface SuperGridProps<ItemType = any> {
    * If true, the grid will be scrolling horizontally
    */
   horizontal?: boolean;
+
+  /**
+   * Optional callback ran by the internal `FlatList` or `SectionList`'s `onLayout` function,
+   * thus invoked on mount and layout changes.
+   */
+  onLayout?: func;
 }
 
 /**
@@ -66,6 +72,7 @@ export interface SuperGridSectionListProps<ItemType = any> {
   style?: StyleProp<ScrollViewStyle>,
   staticDimension?: number,
   renderSectionHeader?: (info: { section: SectionListData<ItemType> }) => JSX.Element;
+  onLayout?: func,
 }
 
 export class SuperGridSectionList<ItemType = any> extends React.Component<

index.js

@@ -23,7 +23,7 @@ class SuperGrid extends Component {
   }
 
   onLayout(e) {
-    const { staticDimension, horizontal } = this.props;
+    const { staticDimension, horizontal, onLayout } = this.props;
     if (!staticDimension) {
       const { width, height } = e.nativeEvent.layout || {};
 
@@ -31,6 +31,10 @@ class SuperGrid extends Component {
         ...this.getDimensions(horizontal ? height : width),
       });
     }
+    // run onLayout callback if provided
+    if (onLayout) {
+      onLayout(e);
+    }
   }
 
   getDimensions(lvDimension, itemDim) {
@@ -142,7 +146,7 @@ class SuperGrid extends Component {
 
   render() {
     const { items, style, spacing, fixed, itemDimension, renderItem,
-      horizontal, ...props } = this.props;
+      horizontal, onLayout, ...props } = this.props;
     const { itemsPerRow } = this.state;
 
     const chunked = chunkArray(items, itemsPerRow); //Splitting the data into rows
@@ -182,6 +186,7 @@ SuperGrid.propTypes = {
   style: ViewPropTypes.style,
   staticDimension: PropTypes.number,
   horizontal: PropTypes.bool,
+  onLayout: PropTypes.func,
 };
 
 SuperGrid.defaultProps = {