C:\Users\tanji\Desktop\QCP\Demo03\mainwindow.cpp:63: error: no member named 'rangeZoom' in 'QCPAxis'
时间: 2023-09-29 16:06:29 浏览: 44
这个错误提示是因为你试图在 `QCPAxis` 类中使用 `rangeZoom` 函数,但是 `QCPAxis` 类并没有这个函数。请检查你的代码,确保你是正确地引用了 `QCPAxis` 类,并且使用了该类中真正存在的函数。如果你确定该函数确实存在于 `QCPAxis` 类中,那么可能是你的 Qt 版本不支持该函数,你需要升级到支持该函数的 Qt 版本。
相关问题
C:\Users\tanji\Desktop\QCP\Demo03\mainwindow.cpp:86: error: 'startSelection' is a protected member of 'QCPSelectionRect'
这个错误是因为你尝试在 `QCPSelectionRect` 类外部调用其受保护的成员函数 `startSelection`,而受保护的成员函数只能在该类的派生类或友元类中访问。
如果你想在 `mainwindow.cpp` 中使用 `startSelection` 函数,你需要将 `QCPSelectionRect` 类的定义添加到 `mainwindow.h` 的头文件中,并在 `QCPSelectionRect` 类的定义前加上 `friend class MainWindow;`,以使 `MainWindow` 类成为 `QCPSelectionRect` 类的友元类。这样,在 `MainWindow` 类中就可以访问 `QCPSelectionRect` 的受保护成员函数了。
示例代码:
mainwindow.h:
```cpp
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "qcustomplot.h"
class QCPSelectionRect;
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private:
Ui::MainWindow *ui;
QCustomPlot *customPlot;
QCPSelectionRect *selectionRect;
private slots:
void selectionRectStarted(QMouseEvent *event);
void selectionRectChanged(const QRect &rect, QMouseEvent *event);
void selectionRectEnded(QMouseEvent *event);
};
#endif // MAINWINDOW_H
```
mainwindow.cpp:
```cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "qcustomplot.h"
class QCPSelectionRect;
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
// create graph and assign data to it:
customPlot = new QCustomPlot(this);
customPlot->addGraph();
QVector<double> x(101), y(101); // initialize with entries 0..100
for (int i=0; i<101; ++i)
{
x[i] = i/50.0 - 1; // x goes from -1 to 1
y[i] = x[i]*x[i]; // let's plot a quadratic function
}
customPlot->graph(0)->setData(x, y);
// set axes ranges, so we see all data:
customPlot->xAxis->setRange(-1, 1);
customPlot->yAxis->setRange(0, 1);
// create selection rect:
selectionRect = new QCPSelectionRect(customPlot);
selectionRect->setPen(QPen(Qt::blue, 2, Qt::DashLine));
// connect signals of selection rect:
connect(selectionRect, SIGNAL(selectionStart(QMouseEvent*)), this, SLOT(selectionRectStarted(QMouseEvent*)));
connect(selectionRect, SIGNAL(selectionChanged(QRect,QMouseEvent*)), this, SLOT(selectionRectChanged(QRect,QMouseEvent*)));
connect(selectionRect, SIGNAL(selectionEnd(QMouseEvent*)), this, SLOT(selectionRectEnded(QMouseEvent*)));
// set central widget:
setCentralWidget(customPlot);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::selectionRectStarted(QMouseEvent *event)
{
customPlot->graph(0)->clearData();
}
void MainWindow::selectionRectChanged(const QRect &rect, QMouseEvent *event)
{
// do something with rect, e.g. translate to QCPAxisRect coordinates, then set this as clipRect for the respective axis rect:
customPlot->xAxis->setRange(customPlot->xAxis->pixelToCoord(rect.left()), customPlot->xAxis->pixelToCoord(rect.right()));
customPlot->yAxis->setRange(customPlot->yAxis->pixelToCoord(rect.bottom()), customPlot->yAxis->pixelToCoord(rect.top()));
customPlot->replot();
}
void MainWindow::selectionRectEnded(QMouseEvent *event)
{
// reset data and axes ranges:
QVector<double> x(101), y(101);
for (int i=0; i<101; ++i)
{
x[i] = i/50.0 - 1;
y[i] = x[i]*x[i];
}
customPlot->graph(0)->setData(x, y);
customPlot->xAxis->setRange(-1, 1);
customPlot->yAxis->setRange(0, 1);
customPlot->replot();
}
// make MainWindow a friend of QCPSelectionRect
class QCPSelectionRect
{
friend class MainWindow;
protected:
void startSelection(QMouseEvent *event) { QCPAbstractItem::startSelection(event); }
};
```
严重性 代码 说明 项目 文件 行 禁止显示状态 错误 C2259 “TestQtUdp”: 无法实例化抽象类 TestQtUdp C:\Users\tanji\Downloads\Compressed\HP-Socket-dev\HP-Socket-dev\Windows\Demo\TestQtUdp\TestQtUdp\main.cpp 7 怎么解决
这个错误的原因是TestQtUdp类是一个抽象类,不能被实例化。解决方法是实现TestQtUdp类中所有的纯虚函数,或者将它们声明为非纯虚函数。
在这个例子中,TestQtUdp类继承了CUdpClientListener类,它包含了一些纯虚函数。您需要在TestQtUdp类中实现这些纯虚函数,或者将它们声明为非纯虚函数。例如:
```cpp
class TestQtUdp : public QMainWindow, public CUdpClientListener {
Q_OBJECT
public:
TestQtUdp(QWidget *parent = nullptr);
~TestQtUdp();
private:
// ...
EnHandleResult OnPrepareListen(IUdpNode* pSender, SOCKET soListen) override;
EnHandleResult OnSend(IUdpNode* pSender, LPCTSTR lpszRemoteAddress, USHORT usRemotePort, const BYTE* pData, int iLength) override;
EnHandleResult OnReceive(IUdpNode* pSender, LPCTSTR lpszRemoteAddress, USHORT usRemotePort, const BYTE* pData, int iLength) override;
EnHandleResult OnError(IUdpNode* pSender, EnSocketOperation enOperation, int iErrorCode, LPCTSTR lpszRemoteAddress, USHORT usRemotePort, const BYTE* pData, int iLength) override;
EnHandleResult OnShutdown(IUdpNode* pSender) override;
// ...
};
```
在这里,我们使用了override关键字,以确保在派生类中正确地覆盖了基类中的虚函数。