我在onShow生命周期里去向后端发送消息,这时切换到其它页面后回来不会执行socketTask.onOpen里的代码 为什么

onShow: function() {

console.log(wx.getStorageSync('phone'));

//获取当前经纬度

this.getLocation();

//获取设备状态

this.getActive();

console.log(socketTask);

if(!socketTask && wx.getStorageSync('isLogin')){

this.connectWebsocket();

}else{

if (wx.getStorageSync('isLogin')) {

socketTask.onMessage((res) => {

console.log(res);

console.log('socketMsg:' + res.data)

const result = res.data;

if (result === 'Charging') {

this.setData({

userStatus: result

})

}

})

socketTask.onOpen(() => {

console.log('socket向后端发送数据')

const phone = wx.getStorageSync('phone') || app.globalData.phone;

console.log('phone' + phone)

socketTask.send({

data:String(phone)

})

})

}

}

},