Add custom menus component

Author: 1uokun

Diff for: README.md

@@ -105,7 +105,7 @@ export default class App extends React.Component {
 | doubleClickInterval    | number                                                                                 | no       | Double click interval.                                                                                                                                                                                                               |                                                           |
 | pageAnimateTime        | number                                                                                 | no       | Set the animation time for page flipping.                                                                                                                                                                                            | `100`                                                     |
 | enablePreload          | boolean                                                                                | no       | Preload the next image                                                                                                                                                                                                               | `false`                                                   |
-
+| menus                  | function<br><br>`({cancel,saveToLocal}) => React.ReactElement<any>`                    | no       | Custom menus, with 2 methods:`cancel` to hide menus and `saveToLocal` to save image to camera
 ## Development pattern
 
 ### Step 1, run TS listener

Diff for: src/image-viewer.component.tsx

@@ -642,6 +642,14 @@ export default class ImageViewer extends React.Component<Props, State> {
       return null;
     }
 
+    if(this.props.menus) {
+      return (
+          <View style={this.styles.menuContainer}>
+            {this.props.menus({cancel:this.handleLeaveMenu,saveToLocal:this.saveToLocal})}
+          </View>
+      )
+    }
+
     return (
       <View style={this.styles.menuContainer}>
         <View style={this.styles.menuShadow} />