Add onLongPress event for picker button

README.md

@@ -83,6 +83,7 @@ Prop                | Type     | Optional | Default   | Description
 `onDropdownWillShow`| func     | Yes      |           | Trigger when dropdown will show by touching the button. **Return `false` can cancel the event.**
 `onDropdownWillHide`| func     | Yes      |           | Trigger when dropdown will hide by touching the button. **Return `false` can cancel the event.**
 `onSelect`          | func     | Yes      |           | Trigger when option row touched with selected `index` and `value`. **Return `false` can cancel the event.**
+`onLongPress`          | func     | Yes      |           | Trigger when the button has received `onLongPress` event
 `accessible`          | bool     | Yes      | true    | Set accessibility of dropdown modal and dropdown rows
 `keyboardShouldPersistTaps`    | enum('always', 'never', 'handled') | Yes | 'never' | See react-native `ScrollView` props
 

components/ModalDropdown.js

@@ -171,6 +171,7 @@ export default class ModalDropdown extends Component {
                         disabled={disabled}
                         accessible={accessible}
                         onPress={this._onButtonPress}
+                        onLongPress={this._onButtonLongPress}
       >
         {
           children ||
@@ -196,6 +197,12 @@ export default class ModalDropdown extends Component {
     }
   };
 
+  _onButtonLongPress = () => {
+    if (this.props.onLongPress) {
+      this.props.onLongPress();
+    }
+  }
+
   _renderModal() {
     const {animated, accessible, dropdownStyle} = this.props;
     const {showDropdown, loading} = this.state;