Question

我在我的Arduino项目中使用AccelStepper库，该库有一个构造函数，函数作为参数：

AccelStepper(void (*forward)(), void (*backward)());

在主草图中，这是使用的代码：

void forwardstep() {
  AFstepper->onestep(FORWARD, stepType);  //some code to move the motor
}
void backwardstep() {
  AFstepper->onestep(BACKWARD, stepType);  //some code to move the motor
}
AccelStepper stepper(forwardstep, backwardstep);

只要此代码在主草图中，一切都运行良好。

我创建了一个具有AccelStepper对象的类，并且forwardstep（）和backwardstep（）函数作为成员，但是我无法将这些函数传递给AccelStepper的构造函数： .h文件：

#define IICADDRESS 0x60

class FilterWheel : public Device
{
public:
    FilterWheel();

    void forwardstep();
    void backwardstep();
    void (*fwdstp)();      //function pointer 
    void (*bckwdstp)();    //function pointer
private:
    //Adafruit Motor Shield object
    Adafruit_MotorShield AFMS; 
    //Adafruit Stepper Motor object
    Adafruit_StepperMotor *AFstepper; 
    //AccelStepper wrapper
    AccelStepper stepper; 
};

.cpp文件：

#include "FilterWheel.h"

//constructor
FilterWheel::FilterWheel()
{
    fwdstp = &FilterWheel::forwardstep;
    bckwdstp = &FilterWheel::backwardstep;

    Adafruit_MotorShield AFMS (IICADDRESS);
    Adafruit_StepperMotor *AFstepper = AFMS.getStepper(200, 1); //M1 M2
    //AccelStepper stepper(forwardstep, backwardstep);  //doesn't work
    AccelStepper stepper(fwdstp, bckwdstp);             //works only if fwdstp = &FilterWheel::forwardstep; and bckwdstp = &FilterWheel::backwardstep; are commented out
}

//go 1 step forward
void FilterWheel::forwardstep() {
    AFstepper->onestep(FORWARD, stepType);
}
//go 1 step backward
void FilterWheel::backwardstep() {
    AFstepper->onestep(BACKWARD, stepType);
}

当我尝试直接传递函数时，

AccelStepper stepper(forwardstep, backwardstep);

编译器显示以下错误：

FilterWheel.cpp:34: error: no matching function for call to 'AccelStepper::AccelStepper(<unresolved overloaded function type>, <unresolved overloaded function type>)'
AccelStepper.h:AccelStepper(void (*)(), void (*)())
AccelStepper.h:AccelStepper(uint8_t, uint8_t, uint8_t, uint8_t, uint8_t, bool)
AccelStepper.h:AccelStepper(const AccelStepper&)
Error compiling

当我将函数附加到函数指针时，

    fwdstp = &FilterWheel::forwardstep;
    bckwdstp = &FilterWheel::backwardstep;
    AccelStepper stepper(fwdstp, bckwdstp);

编译器显示以下错误：

FilterWheel.cpp:In constructor 'FilterWheel::FilterWheel()'
FilterWheel.cpp:22: error: cannot convert 'void (FilterWheel::*)()' to 'void (*)()' in assignment
FilterWheel.cpp:23: error: cannot convert 'void (FilterWheel::*)()' to 'void (*)()' in assignment
Error compiling

我该如何解决这个问题？

Answer 1

forwardstep()和backwardstep()是非静态成员函数，因此fwdstp = &FilterWheel::forwardstep;是指向成员函数的指针，它不能转换为指向函数的指针，因为它需要一个要调用它的对象。

您必须使您的功能保持静态或独立。

传递类成员函数：键入问题

1 个答案: