[RN] Refactor AspectRatioDetector

Factor out the dimensions detection login into a DimensionsDetector component.

react/features/base/aspect-ratio/components/AspectRatioDetector.native.js

-import PropTypes from 'prop-types';
+// @flow
+
 import React, { Component } from 'react';
-import { View } from 'react-native';
 import { connect } from 'react-redux';
 
+import { DimensionsDetector } from '../../dimensions-detector';
+
 import { setAspectRatio } from '../actions';
-import styles from './styles';
 
 /**
- * A root {@link View} which captures the 'onLayout' event and figures out
- * the aspect ratio of the app.
+ * AspectRatioDetector component's property types.
  */
-class AspectRatioDetector extends Component {
+type Props = {
+
     /**
-     * AspectRatioDetector component's property types.
-     *
-     * @static
+     * The "onDimensionsHandler" handler.
      */
-    static propTypes = {
-        /**
-         * The "onLayout" handler.
-         */
-        _onLayout: PropTypes.func,
+    _onDimensionsChanged: Function,
 
-        /**
-         * Any nested components.
-         */
-        children: PropTypes.node
-    };
+    /**
+     * Any nested components.
+     */
+    children: React$Node
+};
 
+/**
+ * A root {@link View} which captures the 'onLayout' event and figures out
+ * the aspect ratio of the app.
+ */
+class AspectRatioDetector extends Component<Props> {
     /**
      * Renders the root view and it's children.
      *
      */
     render() {
         return (
-            <View
-                onLayout = { this.props._onLayout }
-                style = { styles.aspectRatioDetector } >
+            <DimensionsDetector
+                onDimensionsChanged = { this.props._onDimensionsChanged } >
                 { this.props.children }
-            </View>
+            </DimensionsDetector>
         );
     }
 }
  * @param {Function} dispatch - Redux action dispatcher.
  * @private
  * @returns {{
- *     _onLayout: Function
+ *     _onDimensionsChanged: Function
  * }}
  */
 function _mapDispatchToProps(dispatch) {
     return {
         /**
-         * Handles the "on layout" View's event and dispatches aspect ratio
+         * Handles the "on dimensions changed" event and dispatches aspect ratio
          * changed action.
          *
-         * @param {Object} event - The "on layout" event object/structure passed
-         * by react-native.
+         * @param {number} width - The new width for the component.
+         * @param {number} height - The new height for the component.
          * @private
          * @returns {void}
          */
-        _onLayout({ nativeEvent: { layout: { height, width } } }) {
+        _onDimensionsChanged(width: number, height: number) {
             dispatch(setAspectRatio(width, height));
         }
     };

react/features/base/dimensions-detector/components/DimensionsDetector.native.js

+// @flow
+
+import React, { Component } from 'react';
+import { View } from 'react-native';
+
+import styles from './styles';
+
+/**
+ * AspectRatioDetector component's property types.
+ */
+type Props = {
+
+    /**
+     * The "onLayout" handler.
+     */
+    onDimensionsChanged: Function,
+
+    /**
+     * Any nested components.
+     */
+    children: React$Node
+};
+
+/**
+ * A {@link View} which captures the 'onLayout' event and calls a prop with the
+ * component size.
+ */
+export default class DimensionsDetector extends Component<Props> {
+    /**
+     * Initializes a new DimensionsDetector instance.
+     *
+     * @param {Object} props - The read-only properties with which the new
+     * instance is to be initialized.
+     */
+    constructor(props: Object) {
+        super(props);
+
+        this._onLayout = this._onLayout.bind(this);
+    }
+
+    _onLayout: (Object) => void;
+
+    /**
+     * Handles the "on layout" View's event and calls the onDimensionsChanged
+     * prop.
+     *
+     * @param {Object} event - The "on layout" event object/structure passed
+     * by react-native.
+     * @private
+     * @returns {void}
+     */
+    _onLayout({ nativeEvent: { layout: { height, width } } }) {
+        const { onDimensionsChanged } = this.props;
+
+        onDimensionsChanged && onDimensionsChanged(width, height);
+    }
+
+    /**
+     * Renders the root view and it's children.
+     *
+     * @returns {Component}
+     */
+    render() {
+        return (
+            <View
+                onLayout = { this._onLayout }
+                style = { styles.dimensionsDetector } >
+                { this.props.children }
+            </View>
+        );
+    }
+}

react/features/base/dimensions-detector/components/index.js

+export { default as DimensionsDetector } from './DimensionsDetector';

react/features/base/aspect-ratio/components/styles.js → react/features/base/dimensions-detector/components/styles.js

  */
 export default createStyleSheet({
     /**
-     * The style of {@link AspectRatioDetector} used on react-native.
+     * The style of {@link DimensionsDetector} used on react-native.
      */
-    aspectRatioDetector: {
+    dimensionsDetector: {
         alignSelf: 'stretch',
         flex: 1
     }

react/features/base/dimensions-detector/index.js

+export * from './components';