Agency_WxApp/miniprogram/components/localPicker/localPicker.wxml

<picker bindchange="_selectItem" range-key='value' value="{{index}}" range="{{arr}}">
  <view class="df aic arrow-box">
    <view class="picker" style="color:{{arr[index].value?'#6C6C6C':'#777'}}">
      {{arr[index].value||placeholder}}
    </view>
    <image class="arrow" src="../../images/newUI/right-arrow.png"></image>
  </view>
</picker>