Qt+ECharts开发笔记：ECharts的柱状图介绍基础使用和Qt封装Demo
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Qt开发专栏：三方库开发技术
上一篇：《Qt+ECharts开发笔记（二）：Qt窗口动态调整大小，使ECharts跟随Qt窗口大小变换而变换大小》
下一篇：《Qt+ECharts开发笔记（四）：ECharts的饼图介绍、基础使用和Qt封装百分比图Demo》
前言
上一篇成功是EChart随着Qt窗口变化而变化，本篇将开始正式介绍柱状图介绍、基础使用，并将其封装一层Qt。
本篇的demo实现了隐藏js代码的方式，实现了一个条形图的基本交互方式，即Qt调用js脚本操作html。
Demo演示
ECharts调试工具
ECharts提供的纯JS代码编辑开发调试工具，可编辑js，并且查看运行效果：
https://echarts.apache.org/examples/zh/editor.html
开发过程中对于属性的查询和调试ECharts也提供了配置帮助。
官方配置手册：https://echarts.apache.org/zh/option.html
目标
随便找一个预期目标：
ECharts接口静态方式
使用EChart调试工具开发，先调试出基础框架。
这里贴出的全部代码:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>ECharts</title>
<!-- 引入刚刚下载的 ECharts 文件 -->
<!--<script src="echarts.js"></script>-->
<script src="./echarts.js"></script>
<!--<script src="D:/qtProject/echartsDemo/echartsDemo/modules/barEChartWidget/html/echarts.js"></script>-->
<!--<script src="echarts.min.js"></script>-->
<!--<script src="./echarts.min.js"></script>-->
<!--<script src="./html/echarts.min.js"></script>-->
<!--<script src="D:/qtProject/echartsDemo/echartsDemo/modules/barEChartWidget/html/echarts.min.js"></script>-->
</head>
<body>
<!--设置body跟随查u哪个口，main填充body-->
<style>
#main,
html,
body
width: 100%;
height: 100%;
overflow: hidden;
#main
width: 100%;
height: 100%;
</style>
<div id="main"></div>
<script type="text/javascript">
// 基于准备好的dom，初始化echarts实例
var myChart = echarts.init(document.getElementById('main'));
// 窗口高度变化设置
window.onresize = function()
myChart.resize();
;
// 指定图表的配置项和数据
var option =
title:
text: 'ECharts 入门示例'
,
tooltip: ,
legend:
data: ['销量']
,
xAxis:
data: ['衬衫', '羊毛衫', '雪纺衫', '裤子', '高跟鞋', '袜子']
,
yAxis: ,
series: [
name: '销量',
type: 'bar',
data: [5, 20, 36, 10, 10, 20]
]
;
// 使用刚指定的配置项和数据显示图表。
myChart.setOption(option);
function initJs()
var myChart = echarts.init(document.getElementById('main'));
var option;
option =
tooltip:
trigger: 'axis'
,
grid:
left: '3%',
right: '4%',
bottom: '50',
containLabel: true
,
legend:
orient: 'horizontal',
x: 'center',
y: 'bottom',
itemGap: 100
,
xAxis:
type: 'value'
,
yAxis:
type: 'category',
data: ['项目1', '项目2', '项目3']
,
series: [
name: '变量1',
type: 'bar',
stack: 'totla',
label:
show: true
,
data: [11, 12, 13]
,
name: '子项目1',
type: 'bar',
stack: 'totla',
label:
show: true
,
data: [24, 20, 21]
,
name: '变量3',
type: 'bar',
stack: 'totla',
label:
show: true
,
data: [95, 87, 55]
]
;
;
initJs();
</script>
</body>
</html>
ECharts接口动态方式
动态方式，最初目的是为了动态实现数据的js操作，在开发过程中发现动态方式还能隐藏echarts代码，使echarts代码不被抓取，最后决定全部改为动态加载方式。
步骤一：修改html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>ECharts</title>
<script src="./echarts.js"></script>
</head>
<body>
<style>
#main,
html,
body
width: 100%;
height: 100%;
overflow: hidden;
#main
width: 95%;
height: 95%;
</style>
<div id="main"></div>
<script type="text/javascript">
var myChart = echarts.init(document.getElementById('main'));
window.onresize = function()
myChart.resize();
;
</script>
</body>
</html>
步骤二：初始化
新增了loadFinished信号槽关联。
void BarEChartWidget::initControl()
_pWebEngineView = new QWebEngineView(this);
_pWebEnginePage = new QWebEnginePage(this);
_pWebChannel = new QWebChannel(this);
QString filePath;
#if 1
filePath = QString("%1/%2").arg(_htmlDir).arg(_indexFileName);
#else
filePath = "qrc:/barEChartWidget/html/barEChartWidget.html";
#endif
LOG << "file exist:" << QFile::exists(filePath) << filePath;
#if 0
// 打印html文件内容
QFile file(_indexFilePath);
file.open(QIODevice::ReadOnly);
LOG << QString(file.readAll());
file.close();
#endif
connect(_pWebEnginePage, SIGNAL(loadFinished(bool)), this, SLOT(slot_loadFinished(bool)));
_pWebEnginePage->load(QUrl(filePath));
_pWebEnginePage->setWebChannel(_pWebChannel);
_pWebEngineView->setPage(_pWebEnginePage);
// 背景透明
// _pWebEngineView->setStyleSheet("background-color: transparent");
_pWebEnginePage->setBackgroundColor(Qt::transparent);
步骤三：加载完成页面后进行初始化
void BarEChartWidget::slot_loadFinished(bool result)
if(result)
initJs();
void BarEChartWidget::initJs()
_initJsStr = QSTRING(
"var option;"
"option = "
" tooltip: "
" trigger: 'axis'"
" ,"
" grid: "
" left: '10',"
" right: '10',"
" top: '10',"
" bottom: 30,"
" containLabel: true"
" ,"
" legend: "
" orient: 'horizontal',"
" x: 'center',"
" y: 'bottom',"
" itemGap: 20"
" ,"
" xAxis: "
" type: 'value'"
" ,"
" yAxis: "
" type: 'category',"
" data: ['项目1', '项目2', '项目3']"
" ,"
" series: ["
" "
" name: '变量1',"
" type: 'bar',"
" stack: 'totla',"
" label: "
" show: true"
" ,"
" data: [11, 12, 13]"
" ,"
" "
" name: '变量2',"
" type: 'bar',"
" stack: 'totla',"
" label: "
" show: true"
" ,"
" data: [24, 20, 21]"
" ,"
" "
" name: '变量3',"
" type: 'bar',"
" stack: 'totla',"
" label: "
" show: true"
" ,"
" data: [95, 87, 55]"
" "
" ]"
";"
"myChart.setOption(option);");
runJsScript(_initJsStr);
void BarEChartWidget::runJsScript(QString str)
if(_pWebEnginePage)
_pWebEnginePage->runJavaScript(str);
步骤四：动态执行js操作
重置
void BarEChartWidget::on_pushButton_reset_clicked()
initJs();
刷新
void BarEChartWidget::on_pushButton_flush_clicked()
QString jsStr =
"var empty = ;"
"myChart.setOption(empty, true);"
"myChart.setOption(option, true);";
runJsScript(jsStr);
清空
void BarEChartWidget::on_pushButton_clear_clicked()
QString jsStr =
"option.series[0].data = [];"
"option.series[1].data = [];"
"option.series[2].data = [];"
"myChart.setOption(option, true);";
runJsScript(jsStr);
随机生成（使用js代码）
void BarEChartWidget::on_pushButton_createRandom_clicked()
QString jsStr =
"var min = 0;"
"var max = 100;"
"for(var i = 0; i < option.series.length; i++)"
""
" for(var j = 0; j < option.yAxis.data.length; j++)"
" "
" option.series[i].data[j] = Math.floor(Math.random() * (max - min)) + min;"
" "
""
"myChart.setOption(option, true);";
runJsScript(jsStr);
后续用会将数据进行Qt的一份缓存数据，由Qt的数据去生成ecahrts的js脚本。
Demo
html文件
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>ECharts</title>
<script src="./echarts.js"></script>
</head>
<body>
<style>
#main,
html,
body
width: 100%;
height: 100%;
overflow: hidden;
#main
width: 95%;
height: 95%;
</style>
<div id="main"></div>
<script type="text/javascript">
var myChart = echarts.init(document.getElementById('main'));
window.onresize = function()
myChart.resize();
;
</script>
</body>
</html>
在代码中使用js初始化echarts：
BarECartWidget.h
#ifndef BARECHARTWIDGET_H
#define BARECHARTWIDGET_H
#include <QWidget>
#include <QWebEngineView>
#include <QWebEnginePage>
#include <QWebChannel>
namespace Ui
class BarEChartWidget;
class BarEChartWidget : public QWidget
Q_OBJECT
public:
explicit BarEChartWidget(QWidget *parent = 0);
~BarEChartWidget();
protected:
void initControl();
protected slots:
void slot_loadFinished(bool result);
protected:
void initJs();
protected:
void runJsScript(QString str);
protected:
void resizeEvent(QResizeEvent *event);
private slots:
void on_pushButton_clear_clicked();
void on_pushButton_flush_clicked();
void on_pushButton_createRandom_clicked();
void on_pushButton_reset_clicked();
private:
Ui::BarEChartWidget *ui;
private:
QWebEngineView *_pWebEngineView; // 浏览器窗口
QWebEnginePage *_pWebEnginePage; // 浏览器页面
QWebChannel *_pWebChannel; // 浏览器js交互
QString _htmlDir; // html文件夹路径
QString _indexFileName; // html文件
QString _initJsStr; // 第一次初始化的表格
;
#endif // BARECHARTWIDGET_H
BarEChartWidget.cpp
#include "BarEChartWidget.h"
#include "ui_BarEChartWidget.h"
#include <QFile>
#include <QMessageBox>
#include <QTimer>
// QtCreator在msvc下设置编码也或有一些乱码，直接一刀切,避免繁琐的设置
//#define MSVC
#ifdef MSVC
#define QSTRING(s) QString::fromLocal8Bit(s)
#else
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