我可以使用onclick函数进行颜色更改，但是我应该遵循以下逻辑：
1）最后一个栏的颜色总是与其他栏不同。要启动图表，就像单击第一个栏一样。
2）单击其他栏时，颜色必须进行更改，以向用户显示该栏已被单击，但是先前的栏应返回其正常颜色..
我在使用此逻辑时遇到困难，并且正在使用chartjs 2.x
class ChartVenda {
constructor(_id, _dataJSON){
this.id = _id;
this.dataJSON = _dataJSON;
this.chartElement = document.getElementById(_id).getContext('2d');
}
set chartObject(_object){ this.object = _object; }
get chartObject( ){ return this.object; }
get labels(){
return ['jan', 'fev', 'mar', 'abr', 'mai', 'jun', 'jul', 'ago', 'set', 'out', 'nov', 'dez'];
}
get bgColors(){
return [
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)',
'rgb(202, 216, 229)'
]
}
get borderColors(){
return [
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
'rgba(0,0,0,0.3)',
]
}
createChart(){
this.generateChart();
this.addChartOptions();
this.addDataJsonInChart();
this.addChartLabels();
this.addChartDatasets();
this.addAnimation();
this.chartObject.update();
console.log(this.chartObject.data.datasets)
}
generateChart(){
let chartVenda = new Chart(this.chartElement, { type: 'bar'});
this.chartObject = chartVenda;
}
addDataJsonInChart(){
this.chartObject.data.dataJSON = this.dataJSON;
}
addChartLabels(){
let counterLabels = 0;
this.dataJSON.records.forEach( () => {
counterLabels += 1;
this.chartObject.data.labels.push(this.labels[counterLabels-1]);
});
}
addChartDatasets(){
let arrDeltaVendam2 = [];
this.dataJSON.records.forEach( (_item) => {
arrDeltaVendam2.push(_item['Δ% Venda m²']);
});
this.chartObject.data.datasets.push({
label: `ae`,
data: arrDeltaVendam2,
backgroundColor: 'rgb(202, 216, 229)',
borderColor: 'rgb(202, 216, 229)',
});
this.chartObject.update();
}
addChartOptions(){
this.chartObject.options = {
responsive: true,
maintainAspectRatio: false,
legend: { display: false },
scales: {
yAxes: [{ ticks: {display: false, fontColor: 'white'}, gridLines: {display: false, drawBorder: false} }],
xAxes: [{ ticks: {fontSize: 15, fontColor: 'white' }, gridLines: {display: false, drawBorder: false} }],
},
onClick: function(_event, _value) {
let datasetIndex,
dataset;
if (_value.length) {
this.chart.data.dataJSON.records.forEach( (item) => {
if(item['Competência'] === _value[0]._model.label){
const VENDA_METROS_TESTE = document.getElementById('primary-jumbotron-subtitle-indicator-m²'),
VENDA_ABS_TESTE = document.getElementById('primary-jumbotron-subtitle-indicator-abs');
VENDA_METROS_TESTE.innerHTML = `${item['Venda m²']} m²`;
VENDA_ABS_TESTE.innerHTML = `${item['Venda']} abs`;
}
});
datasetIndex = _value[0]._datasetIndex;
// Reset old state
dataset = this.chart.data.datasets[datasetIndex];
dataset.backgroundColor = dataset.backgroundColor.slice();
dataset.backgroundColor = 'rgb(133, 222, 252)'; // click color
} else {
// remove hover styles
for (datasetIndex = 0; datasetIndex < myChart.data.datasets.length; ++datasetIndex) {
dataset = this.chart.data.datasets[index];
dataset.backgroundColor = dataset.backgroundColor.slice();
}
}
}
}
}
addAnimation(){
this.chartObject.options.animation = {
duration: 1000,
onProgress: function() {
/** @description <CRIA O EFEITO DE TEXTO EM CIMA DAS BARRAS> **/
const CHART_OBJECT = this.chart;
CHART_OBJECT.ctx.font = Chart.helpers.fontString('17', 'normal', Chart.defaults.global.defaultFontFamily);
CHART_OBJECT.ctx.fillStyle = 'white';
CHART_OBJECT.ctx.textAlign = 'center';
CHART_OBJECT.ctx.textBaseline = 'bottom';
Chart.helpers.each(this.data.datasets.forEach(function (_dataset, _index1) {
Chart.helpers.each(CHART_OBJECT.getDatasetMeta(_index1).data.forEach(function (_bar, _index2) {
let centerPoint = _bar.getCenterPoint();
CHART_OBJECT.ctx.fillText(_dataset.data[_index2], centerPoint.x, centerPoint.y);
}), this);
}), this);
},
}
}
}
答案 0 :(得分：1)
我不明白你的第一点，但是要解决你的第二点：
以下代码段为每个栏设置了默认颜色（“浅灰色”）。单击条形时，所有条形均设置为原始颜色，并且所单击的条形设置为“红色”。这种方法的好处是每个条形的起始颜色可以不同，并且可以正确地切换为“红色”和“红色”。
let background = ['lightgrey', 'lightgrey', 'lightgrey', 'lightgrey'],
myChart = new Chart(document.getElementById('chart'), {
type: 'bar',
data: {
labels: ['a', 'b', 'c', 'd'],
datasets: [{
label: 'series1',
data: [7, 10, 8, 2],
backgroundColor: background.slice() // using .slice here 'clones' the array.
}]
},
options: {
maintainAspectRatio: false,
onClick: function(e, elems) {
if (elems.length) {
elems[0]._chart.config.data.datasets[0].data.forEach((value, index) => {
// set element to the original colour (resets all).
elems[0]._chart.config.data.datasets[0].backgroundColor[index] = background[index];
if (index == elems[0]._index) {
// set the clicked element to red.
elems[0]._chart.config.data.datasets[0].backgroundColor[index] = 'red';
}
});
myChart.update(); // if you don't want the animation use 'myChart.update(0);' instead.
}
}
}
});<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.min.js"></script>
<canvas id="chart"></canvas>
注释：
elems[0]...datasets[0]）。