使用带省道的amCharts,can';无法从回调中显示图表
我尝试用从dart应用程序调用的js lib amCharts显示一个简单的序列图 在下面的代码中,main()中对display()的第一个调用会按预期显示图表 但是,当我注释第一个display()并单击按钮从回调调用display()时,图表不会出现使用带省道的amCharts,can';无法从回调中显示图表,charts,dart,dart-js-interop,Charts,Dart,Dart Js Interop,我尝试用从dart应用程序调用的js lib amCharts显示一个简单的序列图 在下面的代码中,main()中对display()的第一个调用会按预期显示图表 但是,当我注释第一个display()并单击按钮从回调调用display()时,图表不会出现 import 'dart:js'; import 'dart:html'; main(){ ButtonElement button = new Element.tag("button"); button.type = "submi
import 'dart:js';
import 'dart:html';
main(){
ButtonElement button = new Element.tag("button");
button.type = "submit";
querySelector("#button").append(button);
button.onClick.listen((event) => someCallback());
display(); // this call does display the chart
}
someCallback() {
display(); // this call does not display the chart
}
display() {
var chartData = [
{
"date": "2012-03-01",
"price": 20
},
{
"date": "2012-03-02",
"price": 75
},
{
"date": "2012-03-03",
"price": 10
}
];
context['AmCharts'].callMethod('ready', [(){
var chart2 = new JsObject(context['AmCharts']['AmSerialChart']);
chart2['dataProvider'] = new JsObject.jsify(chartData);
chart2['categoryField'] = "date";
chart2['dataDateFormat'] = "YYYY-MM-DD";
var categoryAxis = chart2['categoryAxis'];
categoryAxis['parseDates'] = true;
categoryAxis['minPeriod'] = "DD";
categoryAxis['dashLength'] = 1;
var valueAxis = new JsObject(context['AmCharts']['ValueAxis']);
valueAxis['axisColor'] = "#DADADA";
valueAxis['dashLength'] = 1;
chart2.callMethod('addValueAxis', [valueAxis]);
var graph = new JsObject(context['AmCharts']['AmGraph']);
graph['title'] = "Price";
graph['valueField'] = "price";
chart2.callMethod('addGraph', [graph]);
chart2.callMethod('write', ["chart"]);
}]);
}
虽然我找不到amChart.ready的文档,但我怀疑只有在amChart准备好后才会调用它。所以,也许一旦它已经准备好了,当你调用它的时候,什么都没有做 您可以尝试将
context['AmCharts'].callMethod('ready',[…
从display
移动到main
:
导入'dart:js';
导入“dart:html”;
main(){
ButtoneElement button=新元素标记(“按钮”);
button.type=“提交”;
查询选择器(“按钮”)。追加(按钮);
listen((事件)=>someCallback());
context['AmCharts'].callMethod('ready',[display]);
}
someCallback(){
display();//此调用不显示图表
}
显示(){
var图表数据=[
{
“日期”:“2012-03-01”,
“价格”:20
},
{
“日期”:“2012-03-02”,
“价格”:75
},
{
“日期”:“2012-03-03”,
“价格”:10
}
];
var chart2=新的JsObject(上下文['AmCharts']['AmSerialChart']);
chart2['dataProvider']=新的JsObject.jsify(chartData);
图表2['categoryField']=“日期”;
图表2['dataDateFormat']=“YYYY-MM-DD”;
变量categoryAxis=chart2['categoryAxis'];
categoryAxis['parseDates']=true;
分类轴['minPeriod']=“DD”;
类别轴['dashLength']=1;
var valueAxis=newjsobject(上下文['AmCharts']['valueAxis']);
valueAxis['axisColor']=“#DADADA”;
valueAxis['dashLength']=1;
图2.调用方法('addValueAxis',[valueAxis]);
var-graph=newjsobject(上下文['AmCharts']['AmGraph']);
图['title']=“价格”;
图['valueField']=“价格”;
图2.callMethod('addGraph',[graph]);
chart2.callMethod('write',[“chart”]);
}
感谢@Alexandre Ardhuin的回答,我找到了解决方法。有趣的是,我不需要调用“ready”方法:
import 'dart:js';
import 'dart:html';
main(){
ButtonElement button = new Element.tag("button");
button.type = "submit";
querySelector("#button").append(button);
button.onClick.listen((event) => someCallback());
}
someCallback() {
display(); // this call _does_ display the chart
}
display() {
var chartData = [
{
"date": "2012-03-01",
"price": 20
},
{
"date": "2012-03-02",
"price": 75
},
{
"date": "2012-03-03",
"price": 10
}
];
var chart2 = new JsObject(context['AmCharts']['AmSerialChart']);
chart2['dataProvider'] = new JsObject.jsify(chartData);
chart2['categoryField'] = "date";
chart2['dataDateFormat'] = "YYYY-MM-DD";
var categoryAxis = chart2['categoryAxis'];
categoryAxis['parseDates'] = true;
categoryAxis['minPeriod'] = "DD";
categoryAxis['dashLength'] = 1;
var valueAxis = new JsObject(context['AmCharts']['ValueAxis']);
valueAxis['axisColor'] = "#DADADA";
valueAxis['dashLength'] = 1;
chart2.callMethod('addValueAxis', [valueAxis]);
var graph = new JsObject(context['AmCharts']['AmGraph']);
graph['title'] = "Price";
graph['valueField'] = "price";
chart2.callMethod('addGraph', [graph]);
chart2.callMethod('write', ["chart"]);
}
当我按照你的建议去做的时候,图表不需要点击按钮就可以显示,点击按钮也不会显示。但是由于这个想法,我找到了如何让它工作的方法!很高兴你发现了这个问题。