picker

從底部彈起的滾動選擇器，現支援五種選擇器，通過mode來區分，分別是普通選擇器，多列選擇器，時間選擇器，日期選擇器，省市區選擇器，預設是普通選擇器。

普通選擇器：mode = selector

多列選擇器：mode = multiSelector（最低版本：1.4.0）

時間選擇器：mode = time

日期選擇器：mode = date

fields 有效值：

省市區選擇器：mode = region（最低版本：1.4.0）

示例程式碼：

在開發者工具中預覽效果

<view class="section">
  <view class="section__title">普通選擇器</view>
  <picker bindchange="bindPickerChange" value="{{index}}" range="{{array}}">
    <view class="picker">
      當前選擇：{{array[index]}}
    </view>
  </picker>
</view>
<view class="section">
  <view class="section__title">多列選擇器</view>
  <picker mode="multiSelector" bindchange="bindMultiPickerChange" bindcolumnchange="bindMultiPickerColumnChange" value="{{multiIndex}}" range="{{multiArray}}">
    <view class="picker">
      當前選擇：{{multiArray[0][multiIndex[0]]}}，{{multiArray[1][multiIndex[1]]}}，{{multiArray[2][multiIndex[2]]}}
    </view>
  </picker>
</view>
<view class="section">
  <view class="section__title">時間選擇器</view>
  <picker mode="time" value="{{time}}" start="09:01" end="21:01" bindchange="bindTimeChange">
    <view class="picker">
      當前選擇: {{time}}
    </view>
  </picker>
</view>

<view class="section">
  <view class="section__title">日期選擇器</view>
  <picker mode="date" value="{{date}}" start="2015-09-01" end="2017-09-01" bindchange="bindDateChange">
    <view class="picker">
      當前選擇: {{date}}
    </view>
  </picker>
</view>
<view class="section">
  <view class="section__title">省市區選擇器</view>
  <picker mode="region" bindchange="bindRegionChange" value="{{region}}" custom-item="{{customItem}}">
    <view class="picker">
      當前選擇：{{region[0]}}，{{region[1]}}，{{region[2]}}
    </view>
  </picker>
</view>

Page({
  data: {
    array: ['美國', '中國', '巴西', '日本'],
    objectArray: [
      {
        id: 0,
        name: '美國'
      },
      {
        id: 1,
        name: '中國'
      },
      {
        id: 2,
        name: '巴西'
      },
      {
        id: 3,
        name: '日本'
      }
    ],
    index: 0,
    multiArray: [['無脊柱動物', '脊柱動物'], ['扁性動物', '線形動物', '環節動物', '軟體動物', '節肢動物'], ['豬肉絛蟲', '吸血蟲']],
    objectMultiArray: [
      [
        {
          id: 0,
          name: '無脊柱動物'
        },
        {
          id: 1,
          name: '脊柱動物'
        }
      ], [
        {
          id: 0,
          name: '扁性動物'
        },
        {
          id: 1,
          name: '線形動物'
        },
        {
          id: 2,
          name: '環節動物'
        },
        {
          id: 3,
          name: '軟體動物'
        },
        {
          id: 3,
          name: '節肢動物'
        }
      ], [
        {
          id: 0,
          name: '豬肉絛蟲'
        },
        {
          id: 1,
          name: '吸血蟲'
        }
      ]
    ],
    multiIndex: [0, 0, 0],
    date: '2016-09-01',
    time: '12:01',
    region: ['廣東省', '廣州市', '海珠區'],
    customItem: '全部'
  },
  bindPickerChange: function(e) {
    console.log('picker傳送選擇改變，攜帶值為', e.detail.value)
    this.setData({
      index: e.detail.value
    })
  },
  bindMultiPickerChange: function (e) {
    console.log('picker傳送選擇改變，攜帶值為', e.detail.value)
    this.setData({
      multiIndex: e.detail.value
    })
  },
  bindMultiPickerColumnChange: function (e) {
    console.log('修改的列為', e.detail.column, '，值為', e.detail.value);
    var data = {
      multiArray: this.data.multiArray,
      multiIndex: this.data.multiIndex
    };
    data.multiIndex[e.detail.column] = e.detail.value;
    switch (e.detail.column) {
      case 0:
        switch (data.multiIndex[0]) {
          case 0:
            data.multiArray[1] = ['扁性動物', '線形動物', '環節動物', '軟體動物', '節肢動物'];
            data.multiArray[2] = ['豬肉絛蟲', '吸血蟲'];
            break;
          case 1:
            data.multiArray[1] = ['魚', '兩棲動物', '爬行動物'];
            data.multiArray[2] = ['鯽魚', '帶魚'];
            break;
        }
        data.multiIndex[1] = 0;
        data.multiIndex[2] = 0;
        break;
      case 1:
        switch (data.multiIndex[0]) {
          case 0:
            switch (data.multiIndex[1]) {
              case 0:
                data.multiArray[2] = ['豬肉絛蟲', '吸血蟲'];
                break;
              case 1:
                data.multiArray[2] = ['蛔蟲'];
                break;
              case 2:
                data.multiArray[2] = ['螞蟻', '螞蟥'];
                break;
              case 3:
                data.multiArray[2] = ['河蚌', '蝸牛', '蛞蝓'];
                break;
              case 4:
                data.multiArray[2] = ['昆蟲', '甲殼動物', '蛛形動物', '多足動物'];
                break;
            }
            break;
          case 1:
            switch (data.multiIndex[1]) {
              case 0:
                data.multiArray[2] = ['鯽魚', '帶魚'];
                break;
              case 1:
                data.multiArray[2] = ['青蛙', '娃娃魚'];
                break;
              case 2:
                data.multiArray[2] = ['蜥蜴', '龜', '壁虎'];
                break;
            }
            break;
        }
        data.multiIndex[2] = 0;
        break;
    }
    console.log(data.multiIndex);
    this.setData(data);
  },
  bindDateChange: function(e) {
    console.log('picker傳送選擇改變，攜帶值為', e.detail.value)
    this.setData({
      date: e.detail.value
    })
  },
  bindTimeChange: function(e) {
    console.log('picker傳送選擇改變，攜帶值為', e.detail.value)
    this.setData({
      time: e.detail.value
    })
  },
  bindRegionChange: function (e) {
    console.log('picker傳送選擇改變，攜帶值為', e.detail.value)
    this.setData({
      region: e.detail.value
    })
  }
})