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這段是從串口接收到的

{"M":"say","ID":"U123","S":"D999","C":"{\"n\":\"SetBrightness\",\"a\":\"brightness\",\"v\":\"50\"}","SIGN":"Aligenie","T":"1577109735"}

可以從 C 提取出 v 的值嗎？

重要代碼如下

void serialEvent()
{
if (Serial.available()>0)
{
String inputString = Serial.readStringUntil('\n');
inputString.trim();
Serial.println(inputString);
int len = inputString.length()+1;
if(inputString.startsWith("{") && inputString.endsWith("}"))
{
char jsonString[len];
inputString.toCharArray(jsonString,len);
aJsonObject *msg = aJson.parse(jsonString);
processMessage(msg);
aJson.deleteItem(msg);
}
}

- --- -- - ----- ------------------------------------------

void processMessage(aJsonObject *msg){
aJsonObject* method = aJson.getObjectItem(msg, "M");
aJsonObject* content = aJson.getObjectItem(msg, "C");
aJsonObject* contentV = aJson.getObjectItem(content, "v");

if (!method)
{
return;
}
String M=method->valuestring;
String C=content->valuestring;
String V=contentV->valuestring;

if(M=="say")
{
if(V == "50" )
{
Serial.println(V);
}

}

評論：共5條

貝殼物聯 評論于：2019-12-26 09:21:12

可以把C值當做JSON字符串再次解析，就跟處理收到的的msg一樣。

1983king 回復于：2019-12-26 21:44:32

回復 @貝殼物聯:明白，謝謝

SPOPULAY 評論于：2020-01-04 22:49:37

if (C == "play") Serial.println("play");
else if (C == "stop")Serial.println("stop");
else
{
aJsonObject *A = bigiot.getJsonObj(C);
aJsonObject* contentV = aJson.getObjectItem(A, "v");
String V = contentV->valuestring;
Serial.println(V);
}

Arm 回復于：2020-02-22 21:28:29

回復 @SPOPULAY:讀取S 也一樣嗎，如果使用子設備需要讀取S 的值吧

yangjie 評論于：2020-02-25 22:52:33

按照上面回復的，這樣就可以取到S值了
void processMessage(aJsonObject *msg){
aJsonObject* method = aJson.getObjectItem(msg, "M");
aJsonObject* content = aJson.getObjectItem(msg, "C");
aJsonObject* contentV = aJson.getObjectItem(content, "v");
aJsonObject* contentS = aJson.getObjectItem(content, "S");

if (!method)
{
return;
}
String M=method->valuestring;
String C=content->valuestring;
String V=contentV->valuestring;
String S=contentS->valuestring;