第一步 div下放置chart <canvas id="canvas"></canvas>
<div class="ok-card-body map-body"> <canvas id="canvas"></canvas> <br /> </div>
第二步初始化bar chart 无值
window.chartColors = { red: ‘rgb(255, 99, 132)‘, orange: ‘rgb(255, 159, 64)‘, yellow: ‘rgb(255, 205, 86)‘, green: ‘rgb(75, 192, 192)‘, blue: ‘rgb(54, 162, 235)‘, purple: ‘rgb(153, 102, 255)‘, grey: ‘rgb(201, 203, 207)‘ }; var color = Chart.helpers.color; var barChartData = { labels: [@*‘January‘, ‘February‘, ‘March‘, ‘April‘, ‘May‘, ‘June‘, ‘July‘*@], datasets: [@*{ label: ‘Dataset 1‘, backgroundColor: window.chartColors[‘green‘], borderColor: window.chartColors[‘green‘], borderWidth: 1, data: [ 12, 13, 33, 43, 12, 23, 31 ] }, { label: ‘Dataset 2‘, backgroundColor: window.chartColors[‘green‘], borderColor: window.chartColors[‘green‘], borderWidth: 1, data: [ 12, 13, 33, 43, 12, 23, 31 ] }*@] }; window.onload = function () { var ctx = document.getElementById(‘canvas‘).getContext(‘2d‘); window.myBar = new Chart(ctx, { type: ‘bar‘, data: barChartData, options: { responsive: true, legend: { position: ‘top‘, }, title: { display: true, text: ‘南屋北屋有功电能对比图‘ } } }); };
第三步 初始化 ajax请求数据
initCaiji(); function initCaiji() { $.ajax({ url: ‘/xxx/xxx/GetEveryHourEnergyData‘, type: ‘GET‘, success: function (data1) { console.log(data1); if (data1.length == 0) { alert("此时辰范围内,没有数据"); return; } var labhours = data1[0][‘hours‘]; //初始化x轴 for (var i = 0; i < labhours.length; i++) { barChartData.labels.push(‘时: ‘+labhours[i]+‘点‘); } //根据数量新建datasets for (var i = 0; i < data1.length; i++) { var newDataset = { label: ‘‘, backgroundColor: ‘‘,// color(dsColor).alpha(0.5).rgbString(), borderColor: ‘‘,// dsColor, borderWidth: 1, data: [] }; if (i === 0) //电能表1 柱颜色 { var dsColor = window.chartColors[‘green‘]; newDataset.backgroundColor = color(dsColor).alpha(0.5).rgbString(); newDataset.borderColor = dsColor; } else if (i === 1) //电能表2 { var dsColor1 = window.chartColors[‘yellow‘]; newDataset.backgroundColor = color(dsColor1).alpha(0.5).rgbString(); newDataset.borderColor = dsColor1; } newDataset.label = data1[i][‘devname‘]; //柱名 var engl = data1[i][‘lenergy‘]; for (var index = 0; index < barChartData.labels.length; index++) { newDataset.data.push(parseFloat(engl[index])); } barChartData.datasets.push(newDataset); } window.myBar.update(); } , error: function (err) { // console.log(err.statusText); console.log(‘异常‘); } }); }
注意: 两个柱子y值为整数时, 由于图用的是相对对比,这样有时不显示坐标0点, 如果两个y值 比如( y=20 柱子1 y=30 柱子2),( y=20 柱子1 y=30 柱子2) 这是两组数据, 四个柱子,很可能会把y=20 作为为实际图中y的初始值.
于是造成一个错觉, 左侧的柱子显示不出来.这个错觉让我调试了几个小时...如果看左边的y轴,就能理解..