更新消息列表分享按钮 review by sunkai

@@ -140,12 +140,14 @@ let styles = StyleSheet.create({
     height: 14 
   },
   shareButton: {
-    width: 15 * DEVICE_WIDTH_RATIO,
-    height: 15 * DEVICE_WIDTH_RATIO,
-    justifyContent: 'center'
+    width: 80 * DEVICE_WIDTH_RATIO,
+    height: 25 * DEVICE_WIDTH_RATIO,
+    justifyContent: 'center',
+    alignItems: 'center'
   },
   shareButtonImage: {
-    flex: 1
+    width: 15 * DEVICE_WIDTH_RATIO,
+    height: 15 * DEVICE_WIDTH_RATIO,
   }
 });