# picker开发指导

picker是滑动选择器组件，类型支持普通选择器、日期选择器、时间选择器、时间日期选择器和多列文本选择器。具体用法请参考[picker API](../reference/arkui-js/js-components-basic-picker.md)。


## 创建picker组件

在pages/index目录下的hml文件中创建一个picker组件。

```html
<!-- xxx.hml -->
<div class="container">
  <picker>    picker  </picker>
</div>
```

```css
/* xxx.css */
.container {
  width: 100%;
  height: 100%; 
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #F1F3F5;
}
```

![zh-cn_image_0000001210951541](figures/zh-cn_image_0000001210951541.gif)


## 设置picker类型

通过设置picker的type属性来选择滑动选择器类型，如定义picker为日期选择器。

```html
<!-- xxx.hml -->
<div class="container">
  <picker id="picker_text" type="text" value="{{textvalue}}"range="{{rangetext}}" class="pickertext" ></picker>
  <picker id="picker_date" type="date" value="{{datevalue}}" lunarswitch="true" start="2002-2-5" end="2030-6-5" class="pickerdate"></picker>
</div>
```

```css
/* xxx.css */
.container {
  width: 100%;
  height: 100%;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #F1F3F5;
}
.pickertext{
  margin-bottom: 30px;
}
```

```js
// xxx.js
export default {
  data: {
    rangetext:['15', "20", "25"],
    textvalue:'Select text',
    datevalue:'Select date',
  }
}
```

![zh-cn_image_0000001189098638](figures/zh-cn_image_0000001189098638.gif)

> **说明：**
>
> 普通选择器设置取值范围时，需要使用数据绑定的方式。


## 设置时间展现格式

picker的hours属性定义时间的展现格式，可选类型有12小时制和24小时制。

```html
<!-- xxx.hml -->
<div class="container">
  <picker id="picker_time" type="time" value="12-hour format" hours="12" onchange="timeonchange"  class="pickertime"></picker>
  <picker id="picker_time" type="time" value="24-hour format" hours="24" onchange="timeonchange"  class="pickertime"></picker>
</div>
```

```css
/* xxx.css */
.container {
  width: 100%;
  height: 100%;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #F1F3F5;
}
.pickertime {
  margin-bottom:50px;
  width: 300px;
  height: 50px;
}
```

![zh-cn_image_0000001234327855](figures/zh-cn_image_0000001234327855.gif)

> **说明：**
> - hours属性为12：按照12小时制显示，用上午和下午进行区分；
>
> - hours属性为24：按照24小时制显示。


## 添加响应事件

对picker添加change和cancel事件，来对选择的内容进行确定和取消。

```html
<!-- xxx.hml -->
<div class="container">
  <picker id="picker_multi" type="multi-text" value="{{multitextvalue}}" columns="3" range="{{multitext}}" selected="
     {{multitextselect}}" onchange="multitextonchange" oncancel="multitextoncancel" class="pickermuitl"></picker>
</div>
```

```css
/* xxx.css */
.container {
  width: 100%;
  height: 100%;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #F1F3F5; 
}
.pickermuitl {
  margin-bottom:20px;
  width: 600px;
  height: 50px;
  font-size: 25px;
  letter-spacing:15px;
}
```

```js
// xxx.js
import prompt from '@system.prompt';
export default {
  data: {
    multitext:[["a", "b", "c"], ["e", "f", "g"], ["h", "i"]],
    multitextvalue:'Select multi-line text',
    multitextselect:[0,0,0],
  },
  multitextonchange(e) {
    this.multitextvalue=e.newValue;
    prompt.showToast({ message:"Multi-column text changed to:" + e.newValue })
  },
  multitextoncancel() {
    prompt.showToast({ message:"multitextoncancel" })
  },
}
```

![zh-cn_image_0000001234009343](figures/zh-cn_image_0000001234009343.gif)


## 场景示例


在本场景中，开发者可以自定义填写当前的健康情况来进行打卡。


```html
<!-- xxx.hml -->
<div class="doc-page">
  <text class="title">Health check-in</text>
  <div class="out-container">
    <text class="txt">Office:</text>
    <picker class="pick" focusable="true" type="text" value="{{pos}}" range="{{posarr}}" onchange="setPos"></picker>
  </div>
  <divider class="dvd"></divider>
  <div class="out-container">
    <text class="txt">Office hours:</text>
    <picker class="pick" type="date" value="{{datevalue}}"  start="2002-2-5" end="2030-6-5" selected="{{dateselect}}"
      lunarswitch="true" onchange="dateonchange"></picker>
  </div>
  <divider class="dvd"></divider>
  <div class="out-container">
    <text class="txt">Having fever or cold symptoms</text>
    <picker class="pick" type="text" value="{{yorn1}}" range="{{yesno}}" selected="1" onchange="isFever"></picker>
  </div>
  <divider class="dvd"></divider>
  <div class="out-container">
    <text class="txt">Close contact with someone with COVID-19</text>
    <picker class="pick" type="text" value="{{yorn2}}" range="{{yesno}}" selected="1" onchange="isTouch"></picker>
  </div>
  <div class="out-container">
    <button value="Submit" style="margin-top:100px;width:50%;font-color:#0000ff;height:80px" onclick="showtoast"></button>
  </div>
</div>
```


```css
/* xxx.css */
.doc-page {
  flex-direction: column;
  background-color: #F1F3F5;
}
.title {
  margin-top: 30px;
  margin-bottom: 30px;
  margin-left: 50px;
  font-weight: bold;
  color: #0000ff;
  font-size: 38px;
}
.out-container {
  flex-direction: column;
  align-items: center;
}
.pick {
  width: 80%;
  height: 76px;
  border: 1px solid #0000ff;
  border-radius: 20px;
  padding-left: 12px;
}
.txt {
  width: 80%;
  font-size: 18px;
  text-align: left;
  margin-bottom: 12px;
  margin-left: 12px;
}
.dvd {
  margin-top: 30px;
  margin-bottom: 30px;
  margin-left: 80px;
  margin-right: 80px;
  color: #6495ED;
  stroke-width: 6px;
}
```


```js
// xxx.js
import pmt from '@system.prompt'
export default {
  data: {
    yorn1:'No',
    yorn2:'No',
    pos:'Home',
    yesno:['Yes', 'No'],
    posarr:['Home', 'Company'],
    datevalue:'Select time',
    datetimeselect:'2012-5-6-11-25',
    dateselect:'2021-9-17',
    showbuild:true
  },
  onInit() {
  },
  isFever(e) {
    this.yorn1 = e.newValue
  },
  isTouch(e) {
    this.yorn2 = e.newValue
  },
  setPos(e) {
    this.pos = e.newValue
    if (e.newValue === 'Non-research center') {
      this.showbuild = false
    } else {
      this.showbuild = true
    }
  },
  setbuild(e) {
    this.build = e.newValue
  },
  dateonchange(e) {
    e.month=e.month+1;
    this.datevalue = e.year + "-" + e.month + "-" + e.day;
    pmt.showToast({ message:"date:"+e.year+"-"+e.month+"-"+e.day }) 
  },
  showtoast() {
    pmt.showToast({
      message: 'Submitted.',
      duration: 2000,
      gravity: 'center'
    })
  }
}
```


![zh-cn_image_0000001234342189](figures/zh-cn_image_0000001234342189.gif)


## 相关实例

针对picker开发，有以下相关实例可供参考：

- [`Picker`：滑动选择器（JS）（API8）](https://gitee.com/openharmony/applications_app_samples/tree/master/UI/Picker)