上传多张图片时，如何做到监听每一张图片的上传进度。 运行代码时 upload.onProgressUpdate 这个方法在循环中只能调用一遍。求解！！

js代码：

chooseImage:function(){

var that=this

wx.chooseImage({

count: 5,

sizeType: ['original','compressed'],

sourceType: ['album'],

success: function(res) {

console.log(res)

console.log(res.tempFilePaths.length)

for (var i = 0; i < res.tempFilePaths.length;i++){

var up = wx.uploadFile({

url: '',

filePath: res.tempFilePaths[i],

name: 'file',

success: function (res) {

console.log(res)

console.log('上传完毕啦')

}

})

up.onProgressUpdate((res) => {

console.log('监听进度')

that.setData({

percent: res.progress

})

console.log('上传进度', res.progress)

console.log('已经上传的数据长度', res.totalBytesSent)

console.log('预期需要上传的数据总长度', res.totalBytesExpectedToSend)

})

}

},

fail: function(res) {},

complete: function(res) {},

})

},