[new feature] Picker: add loading prop (#619)

docs/demos/views/picker.vue

@@ -21,6 +21,10 @@
     <demo-block :title="$t('title4')">
       <van-picker :columns="columns" @change="onChange2" />
     </demo-block>
+
+    <demo-block :title="$t('loading')">
+      <van-picker :columns="columns" loading />
+    </demo-block>
   </demo-section>
 </template>
 

docs/markdown/en-US/area.md

@@ -45,6 +45,7 @@ Set `columns-num` with 2, you'll have a 2 level picker.
 | area-list | an object contains these properties: `province_list`, `city_list` and `county_list`  | `Object` | - | - |
 | columns-num | level of picker | `String`,`Number` | 3 | - |
 | item-height | Option height | `Number` | `44` | - |
+| loading | Whether to show loading prompt | `Boolean` | `false` | - |
 | visible-item-count | Count of visible columns | `Number` | `5` | - |
 
 ### Event

docs/markdown/en-US/picker.md

@@ -114,6 +114,13 @@ export default {
 };
 ```
 
+#### Loading
+When Picker columns data is acquired asynchronously, use `loading` prop to show loading prompt
+
+```html
+<van-picker :columns="columns" loading />
+```
+
 ### API
 
 | Attribute | Description | Type | Default | Accepted Values |
@@ -121,6 +128,7 @@ export default {
 | columns | Columns data | `Array` | `[]` | - |
 | show-toolbar | Whether to show toolbar | `Boolean` | `false` | - |
 | title | Toolbar title | `String` | `''` | - |
+| loading | Whether to show loading prompt | `Boolean` | `false` | - |
 | confirm-button-text | Text of confirm button | `String` | `Confirm` | - |
 | cancel-button-text | Text of cancel button | `String` | `Cancel` | - |
 | item-height | Option height | `Number` | `44` | - |

docs/markdown/zh-CN/area.md

@@ -42,6 +42,7 @@ Vue.use(Area);
 | title | 顶部栏标题 | `String` | `''`   | - |
 | area-list | 省市县数据，格式见下方 | `Object` | - | - |
 | columns-num | 省市县显示列数，3-省市县，2-省市，1-省 | `String`,`Number` | `3` | - |
+| loading | 是否显示加载状态 | `Boolean` | `false` | - |
 | item-height | 选项高度 | `Number` | `44` | - |
 | visible-item-count | 可见的选项个数 | `Number` | `5` | - |
 

docs/markdown/zh-CN/picker.md

@@ -116,6 +116,13 @@ export default {
 };
 ```
 
+#### 加载状态
+当 Picker 数据是通过异步获取时，可以通过 `loading` 属性显示加载提示
+
+```html
+<van-picker :columns="columns" loading />
+```
+
 ### API
 
 | 参数 | 说明 | 类型 | 默认值 | 可选值 |
@@ -123,6 +130,7 @@ export default {
 | columns | 对象数组，配置每一列显示的数据 | `Array` | `[]` | - |
 | show-toolbar | 是否显示顶部栏 | `Boolean` | `false` | - |
 | title | 顶部栏标题 | `String` | `''` | - |
+| loading | 是否显示加载状态 | `Boolean` | `false` | - |
 | confirm-button-text | 确认按钮文字 | `String` | `完成` | - |
 | cancel-button-text | 取消按钮文字 | `String` | `取消` | - |
 | item-height | 选项高度 | `Number` | `44` | - |