微信小程序默认获取聚焦事件

 <input type="text"   focus="{{inputShowed}}" />

  // 搜索框状态
    inputShowed: false,

 // 搜索框状态
    inputShowed: true,

<view class="weui-search-bar">
  <view class="weui-search-bar__form">
    <view class="weui-search-bar__box">
      <icon class="weui-icon-search_in-box" type="search" size="14"></icon>
      <input type="text" class="weui-search-bar__input" placeholder="沪A6789" maxlength='10' value="{{inputVal}}" focus="{{inputShowed}}" />
    </view>
  </view>
</view>

/* 搜索 */
.weui-search-bar__input{
  height: 72rpx;
}
.weui-icon-search_in-box{
  top:22rpx;
}
.weui-search-bar__cancel-btn{
  line-height:70rpx;
}
.weui-icon-clear{
  top:4rpx;
}

var app = getApp()
Page({
  data: {
    // 搜索框状态
    inputShowed: false,
    // 搜索框值
    inputVal: "",
  },
  onLoad: function () {
  },

});