我正在构建一个网络应用程序,你可以在其中选择航空公司,并获得一个包含五个类别(公司、食品、行李、守时、员工)分数的条形图。当用户单击图表的不同部分时,我想获取公司名称和类别的值。这是为了在Python中使用companyname和category的值做进一步的事情
例如,在下图中,当用户单击绿色大条(右起第四条)时,我希望我的JS接收company="Air France", category="punctuality"
。我假设我需要对onclick
做些什么,但我无法理解
上下文:根据您在表单框中选择的公司,Python后端将json数据返回给JS。在JS中addGroupBarChart
使用chart.JS绘制图表,并将其嵌入html中的canvas元素中
这是JavaScript的摘录
document.getElementById('button').onclick = function(){
/* returns the companies value chosen from the dropdown */
/* and draw a chart using addGroupBarChart function */
let companies = $("#companies").val();
let headers = new Headers()
let init = {
method : 'GET',
headers : headers
}
let params = {
'companies':companies
}
let url = getWebAppBackendUrl('/get_stats')+'/'+JSON.stringify(params)
let promise = fetch(url, init)
.then(function(response){
response.json()
.then(function(data){
addGroupBarChart(data.barChartGroup.company,
data.barChartGroup.labels);
})
});
}
document.getElementById("bar-chart-group").onclick = function(......) {
/* returns the company and category chosen from the chart */
/* this is the function I don't know how to build */
let activePoints = // here I assume I need getPointsAtEvent(evt) but not sure...
let company = // company value based on the click on the chart
let category = // category value based on the click on the chart
let headers = new Headers()
let init = {
method : 'GET',
headers : headers
}
let params = {
'company':company,
'category':category
}
let url = getWebAppBackendUrl('/get_table')+'/'+JSON.stringify(params)
let promise = fetch(url, init)
.then(function(response) {
response.json()
.then(function(data){
// function to add table
})
});
}
function addGroupBarChart(data, labels) {
/* function to add a bar chart using the data returned from Python backend */
document.getElementById('bar-card').innerHTML = '<canvas id="bar-chart-group" chart-click="onClick"></canvas>';
i = 1
arr = []
data.forEach(function(d){
company = Object.keys(d);
values = d[company]['data'];
dataset_company = {
label:company,
backgroundColor: default_colors[i],
data:values};
console.log("dataset_company", dataset_company);
arr.push(dataset_company);
i+=1;
})
let data_grouped = {
labels: labels,
datasets: arr
};
new Chart(document.getElementById("bar-chart-group"), {
type: "bar",
data: data_grouped,
options: {
title: {
display: false,
text: "Sentiment by category"
}
}
});
}
data
和labels
进入addGroupBarChart
的参数如下
data = [{"Air France":{"data":[0.1, -0.2, 0.3, -0.1, 0.1]}},
{"Lufthansa":{"data":[0.3, -0.2, 0.5, 0.2, 0.1]}}]
labels = ["company", "food", "luggage", "punctuality", "staff"]
我尝试了几种解决方案,包括this一种,但它使我的应用程序即使在单击“显示图表”按钮后也无法显示图表。我上星期开始学习JS,所以很无聊。。。任何帮助都将不胜感激。谢谢大家!
Tags:
您可以定义一个^{} 事件处理程序,但遗憾的是,它的文档记录很差。在您的例子中,它将如下所示,
onBarClicked
是您自己的函数,通过company
和category
调用请查看以下修改后的代码: