Question

目前我正在制作一个用于将自定义文本打印到LCD的课程。

我将lcd对象作为构造函数中的参数传递给类。

Display.h

#ifndef Display_h
#define Display_h

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
#include "Arduino.h"

class Display
{
public:
  Display(LiquidCrystal_I2C *outsideLcd);

private:
 LiquidCrystal_I2C *lcd;
};

#endif

Display.cpp

#include "Arduino.h"
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
#include "Display.h"

Display::Display(LiquidCrystal_I2C *outsideLcd)
{
  lcd = outsideLcd;
  lcd.init();
  lcd.clear();
  lcd.print("Constructor");
}

Example.ino

#include "Display.h"
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2);

Display display(&lcd);

void setup()
{

}

void loop()
{
}

当我在构造函数中调用lcd对象上的函数时，不断收到这些错误。

Display.cpp: In constructor 'Display::Display(LiquidCrystal_I2C*)':
Display.cpp:16: error: request for member 'init' in '((Display*)this)->Display::lcd', which is of non-class type 'LiquidCrystal_I2C*'
Display.cpp:17: error: request for member 'clear' in '((Display*)this)->Display::lcd', which is of non-class type 'LiquidCrystal_I2C*'
Display.cpp:18: error: request for member 'print' in '((Display*)this)->Display::lcd', which is of non-class type 'LiquidCrystal_I2C*'

当我在课堂外使用LCD对象的功能时没有问题。我把对象错误传递给了班级吗？

Answer 1

lcd是一个指针

  lcd.init();
  lcd.clear();
  lcd.print("Constructor");

以上行应纠正如下：

 lcd->init();
  lcd->clear();
  lcd->print("Constructor");

在类中的lcd对象上调用函数

1 个答案: