上圖

代碼

#include <iostream>
#include <random>
#include <qcategoryaxis.h>void MainWindow::testLine()
{//1、創建圖表視圖QChartView* view = new QChartView(this);//2.創建圖表QChart* chart = new QChart();//3.將圖表設置給圖表視圖view->setChart(chart);//設置標題chart->setTitle("");chart->legend()->show();//顯示或者隱藏圖例（默認顯示）//4.構建x軸-日期時間軸QDateTimeAxis* axisX = new QDateTimeAxis(this);//設置軸的標題axisX->setTitleText("");//設置時間軸的范圍,參數是兩個時期時間QDateTimeaxisX->setRange(QDateTime(QDate(2000, 01, 01), QTime(0, 0, 0)),QDateTime(QDate(2000, 01, 10), QTime(0, 0, 0)));//設置刻度個數,刻度數算不好會會導致X軸看起來沒有對中一樣axisX->setTickCount(10);//設置刻度值的格式，和格式化時間字符串一樣axisX->setFormat("MM.dd");axisX->setLabelsAngle(45);//添加軸chart->addAxis(axisX, Qt::AlignBottom);//5.構建y軸-數值軸QValueAxis* axisY = new QValueAxis(this);axisY->setRange(0, 100);axisY->setTickCount(11);axisY->setTitleText("Y");chart->addAxis(axisY, Qt::AlignLeft);//6.構建折線系列QLineSeries* line = new QLineSeries();//設置圖例文本line->setName("tar");QLineSeries* line2 = new QLineSeries();//設置圖例文本line2->setName("reality");for (int  i = 0; i < 7; i++){QString strDate = QString("%1.%2.%3").arg(2000).arg(1).arg(i + 1);{std::random_device rd;  // 用于獲取隨機數種子std::mt19937 gen(rd()); // 以 rd() 作為種子的 Mersenne Twister 引擎// 定義一個均勻分布的整數范圍 [1, 100]std::uniform_int_distribution<> dis(1, 100);line->append(QDateTime(QDate::fromString(strDate, "yyyy.M.d"), QTime(0, 0, 0)).toMSecsSinceEpoch(), dis(gen));}{std::random_device rd;  // 用于獲取隨機數種子std::mt19937 gen(rd()); // 以 rd() 作為種子的 Mersenne Twister 引擎// 定義一個均勻分布的整數范圍 [1, 100]std::uniform_int_distribution<> dis(1, 100);line2->append(QDateTime(QDate::fromString(strDate, "yyyy.M.d"), QTime(0, 0, 0)).toMSecsSinceEpoch(), dis(gen));}}//顯示標簽line->setPointLabelsVisible(true);line2->setPointLabelsVisible(true);//顯示標簽格式line->setPointLabelsFormat("(@yPoint)");line2->setPointLabelsFormat("(@yPoint)");//顯示標簽裁剪line->setPointLabelsClipping(false);line2->setPointLabelsClipping(false);chart->addSeries(line);chart->addSeries(line2);//7、將xy軸附加到折線line->attachAxis(axisX);line->attachAxis(axisY);line2->attachAxis(axisX);line2->attachAxis(axisY);setCentralWidget(view);
}