docs(slider): add slider example

Author: 2534290808

README.md

@@ -22,7 +22,7 @@ To use this plugin, add `flutter_weui` as a [dependency in your pubspec.yaml fil
 - [`MediaBox`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/media_box_example.dart)
 - [`Panel`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/panel_example.dart)
 - [`Picker`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/picker_example.dart)
-- [`Slider`]()
+- [`Slider`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/slider_example.dart)
 - [`Switch`]()
 - [`Toast`]()
 - [`TouchableHighlight`]()

README_zh-CN.md

@@ -22,7 +22,7 @@
 - [`MediaBox`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/media_box_example.dart)
 - [`Panel`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/panel_example.dart)
 - [`Picker`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/picker_example.dart)
-- [`Slider`]()
+- [`Slider`](https://github.com/flutter-studio/flutter-weui/blob/master/example/lib/slider_example.dart)
 - [`Switch`]()
 - [`Toast`]()
 - [`TouchableHighlight`]()

example/lib/slider_example.dart

@@ -0,0 +1,21 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_weui/flutter_weui.dart';
+
+class SliderExample extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text("Slider"),
+      ),
+      body: Center(
+        child:Column(
+          children: <Widget>[
+            WSlider(),
+            WSlider(showValue: true,)
+          ],
+        ),
+      ),
+    );
+  }
+}