如何比较来自 Serial.read() 的字符串? [英] How to compare string from Serial.read()?

问题描述

我从 这个论坛那里得到了这段代码我跟了过去.它对我不起作用，但他们声称代码很好.我已经尝试了几种字符串比较方法，例如 string.equals(string) 和标准 == 运算符，仍然没有运气.

I have this code below where I got from this forum that I followed through. It did not work for me but they claim that the code is fine. I already tried several string comparison methods such as string.equals(string) and the standard == operator, still with no luck.

int ledPin = 13;
String readString;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT); 
  Serial.println("serial on/off test 0021"); // so I can keep track
}

void loop() {
  while (Serial.available()) {
    delay(3);  
    char c = Serial.read();
    readString += c; 
  }
  if (readString.length() >0) {
    if (readString == "on") {
      Serial.println("switching on");
      digitalWrite(ledPin, HIGH);
    }
    if (readString == "off") {
      digitalWrite(ledPin, LOW);
    }
    readString="";
  } 
}

推荐答案

我可以通过简单地在字符串比较之前添加 readString.trim(); 来解决昨晚的问题.这是因为在 arduino 控制台中会有 id 没有打印任何内容的换行符.

I am able to solve last night problem by simply adding readString.trim(); before string comparison. This is because there will be newline character where id did not print anything in the arduino console.

我将函数放在下面的代码中:

I place the function as in my code below:

int ledPin = 13;
String readString;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT); 
  Serial.println("serial on/off test 0021"); // so I can keep track
}

void loop() {

  while (Serial.available()) {
    delay(3);  
    char c = Serial.read();
    readString += c; 
  }
  readString.trim();
  if (readString.length() >0) {
    if (readString == "on"){
      Serial.println("switching on");
      digitalWrite(ledPin, HIGH);
    }
    if (readString == "off")
    {
      Serial.println("switching off");
      digitalWrite(ledPin, LOW);
    }

    readString="";
  } 
}

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