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红胖子(红模仿)的博文大全：开发技术集合（包含Qt实用技术、树莓派、三维、OpenCV、OpenGL、ffmpeg、OSG、单片机、软硬结合等等）持续更新中…（点击传送门）

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：敬请期待…

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:

  
    
    
    
    
    
    
    
    
    
    
  
  

    
    


    

    
  

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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

  
    
    
    
  
  
    
    

    
  

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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);
}
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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);
    }
}
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步骤四：动态执行js操作

重置

void BarEChartWidget::on_pushButton_reset_clicked()
{
    initJs();
}
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刷新

void BarEChartWidget::on_pushButton_flush_clicked()
{
    QString jsStr =
            "var empty = {};"
            "myChart.setOption(empty, true);"
            "myChart.setOption(option, true);";
    runJsScript(jsStr);
}
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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);
}
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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);
}
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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

  
    
    
    
  
  
    
    

    
  

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在代码中使用js初始化echarts：
BarECartWidget.h

#ifndef BARECHARTWIDGET_H
#define BARECHARTWIDGET_H

#include 
#include 
#include 
#include 

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
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BarEChartWidget.cpp

#include "BarEChartWidget.h"
#include "ui_BarEChartWidget.h"

#include 
#include 
#include 

// 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
#define QSTRING(s)  QString(s)
#endif

#include 
#include 
//#define LOG qDebug()<<__FILE__<<__LINE__
//#define LOG qDebug()<<__FILE__<<__LINE__<<__FUNCTION__
//#define LOG qDebug()<<__FILE__<<__LINE__<setupUi(this);

    QString version = "v1.0.0";
    setWindowTitle(QString("基于Qt的ECharts条状图Demo %1(长沙红胖子 QQ:21497936 WX:15173255813 blog:hpzwl.blog.csdn.net").arg(version));

    // 设置无边框，以及背景透明
    // 背景透明，在界面构架时，若为本窗口为其他窗口提升为本窗口时，
    // 则再qss会在主窗口第一级添加frame_all，防止其他窗口提升本窗口而冲掉qss设置
//    setWindowFlag(Qt::FramelessWindowHint);
//    setAttribute(Qt::WA_TranslucentBackground, true);

#if 0
    // 这是方法一：让滚动条不出来(通过大小)，还有一个方法是在html设置body的overflow: hidden
//    resize(600 + 20, 400 + 20);
#endif

    initControl();
}

BarEChartWidget::~BarEChartWidget()
{
    delete ui;
}

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);
}

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);
    }
}

void BarEChartWidget::resizeEvent(QResizeEvent *event)
{
    if(_pWebEngineView)
    {
        _pWebEngineView->setGeometry(ui->label_echarts->geometry());
    }
}

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);
}

void BarEChartWidget::on_pushButton_flush_clicked()
{
    QString jsStr =
            "var empty = {};"
            "myChart.setOption(empty, true);"
            "myChart.setOption(option, true);";
    runJsScript(jsStr);
}

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);
}

void BarEChartWidget::on_pushButton_reset_clicked()
{
    initJs();
}
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入坑

入坑一：调用js函数失败

问题

通过qt代码跑js调用函数失败。

原理

先要等页面加载完成后才能调用定义的函数。

解决

发现是调用成功了，原来只定义也会报这个错误。

由此可以看出，在qt中去初始化需要等待页面加载完成才行。

入坑二：Qt的msvc编译器少数中文乱码

问题

少数中文乱码，加空格等都无法解决。

解决

最终解决了，尝试了QTextCodec等各种都不行，最终：

工程模板v1.2.0

后话

条形图将会根据实际需求持续升级版本，下一篇会继续折线图的基础封装。

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：敬请期待…

若该文为原创文章，转载请注明原文出处
本文章博客地址：https://hpzwl.blog.csdn.net/article/details/125731144

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