V1.0.5 New Example

examples/ExampleReadCustomCommand/easyNexReadCustomCommand/easyNexReadCustomCommand.ino

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+/*
+ * easyNexReadCustomCommand.ino - Simple example code for EasyNextionLibrary
+ * Copyright (c) 2020 Athanasios Seitanis < seithagta@gmail.com >. 
+ * https://www.seithan.com 
+ * All rights reserved. EasyNextionLibrary is licensed under the MIT License
+ * https://opensource.org/licenses/MIT
+ */
+
+/* I have invested time and resources providing open source codes, like this one. 
+ * Please do not hesitate to support my work!
+ * If you found  this work useful and has saved you time and effort,
+ * Just simply paypal me at: seithagta@gmail.com
+ */
+
+ //********************************************************************************
+ //  You can find more examples, tutorials and projects with Nextion on my website
+ //  https://www.seithan.com 
+ //********************************************************************************
+
+// Compatible for Arduino
+
+
+// As example we use 2 arrays (tables) of integers where we are going
+// to change their values with custom commands. 
+/*
+      The format is the known: # len cmd id id2
+
+  where the id referred to the position (element) of the array we want to write on
+  And id2 carries the value to write on the element of array
+  the custom command from Nextion: printh 23 03 4C 00 0A
+
+  4C is the Hex for letter L and we referred to the array dataL[]
+  00 Hex of Dec number 0 used as the index for each array element
+  0A Hex of Dec number 10 is the value we are going to write on element 0
+  After the command executed by our code, the values on dataL[] array will be
+
+  dataL[4] = {10,0,0,0}
+  Same for the dataS[] intead that cmd is the 53 Hex for letter S
+        Documentation to the end of the code
+
+*/
+ int dataL[4] = {0,0,0,0}; //values 0 or 1
+                          // printh 23 03 4C 00 00 
+
+ int dataS[4] = {0,0,0,0}; // values from 0 to 100
+                          // printh 23 03 53 00 00
+
+#include "EasyNextionLibrary.h"  // Include EasyNextionLibrary
+
+EasyNex myNex(Serial); // Create an object of EasyNex class with the name < myNex >
+                       // Set as parameter the Hardware Serial you are going to use
+
+void setup(){
+  myNex.begin(9600); // Begin the object with a baud rate of 9600
+                     // If no parameter was given in the begin(), the default baud rate of 9600 will be used
+
+  delay(500);               // give Nextion some time to finish initialize
+  myNex.writeStr("page 0"); // For synchronizing Nextion page in case of reset to Arduino
+  delay(50);
+  myNex.lastCurrentPageId = 1; // At the first run of the loop, the currentPageId and the lastCurrentPageId
+                               // must have different values, due to run the function firstRefresh()
+}
+
+void loop(){
+  myNex.NextionListen(); // WARNING: This function must be called repeatedly to response touch events
+                         // from Nextion touch panel. Actually, you should place it in your loop function.
+
+  firstRefresh(); 
+}
+
+void easyNexReadCustomCommand(){
+
+ int arrayPlace; // temp variable
+ int value;      // temp variable
+ String numericAttribute;
+
+
+  switch(myNex.cmdGroup){
+
+    case 'L': // Or <case 0x4C:>  If 'L' matches
+      // we are going to write values in specific places in the dataL[] table
+      // read the next byte that determines the position on the table
+      arrayPlace = myNex.readByte();
+
+      // read the next byte that keeps the value for the position
+      value = myNex.readByte();
+
+      // update the array with the new values
+      dataL[arrayPlace] = value;
+
+      // show the updated values of the array on Nextion to check them
+      // use this Line to update only the one that you have change
+      numericAttribute = "n"; numericAttribute += arrayPlace; numericAttribute += ".val";
+      myNex.writeNum(numericAttribute, dataL[arrayPlace]);
+
+       // Uncomment this block to update all the values on Nextion
+       /*
+      myNex.writeNum("n0.val", dataL[0]);
+      myNex.writeNum("n1.val", dataL[1]);
+      myNex.writeNum("n2.val", dataL[2]);
+      myNex.writeNum("n3.val", dataL[3]); */
+
+      break;
+
+    case 'S': // Or <case 0x53:>  If 'S' matches 
+      //  ********* PAGE2 ON NEXTION ********
+      // we are going to write values in specific places in the dataS[] table
+      // from Nextion printh 23 03 53 00 and after that prints n0.val,1 in order to have one byte with the value of n0 attribute.
+      // The value of n0 can take values from 0 to 255 as it is only one byte
+
+      // read the next byte that determines the position on the table
+      arrayPlace = myNex.readByte();
+
+      // read the next byte that keeps the value for the position
+      value = myNex.readByte();
+
+      // update the array with the new values
+      dataS[arrayPlace] = value;
+
+      // show the updated values of the array on Nextion to check them
+      // use this Line to update only the one that you have change
+      numericAttribute = "n"; numericAttribute += (arrayPlace + 4); numericAttribute += ".val";
+      myNex.writeNum(numericAttribute, dataS[arrayPlace]);
+  /*     
+      myNex.writeNum("n4.val", dataS[0]);
+      myNex.writeNum("n5.val", dataS[1]);
+      myNex.writeNum("n6.val", dataS[2]);
+      myNex.writeNum("n7.val", dataS[3]);
+           */
+
+      break;
+  }
+
+}
+
+void firstRefresh(){ // This function's purpose is to update the values of a new page when is first loaded,
+                     // and refreshing all the components with the current values as Nextion shows the Attribute val.
+
+  if(myNex.currentPageId != myNex.lastCurrentPageId){ // If the two variables are different, means a new page is loaded.
+
+
+    switch(myNex.currentPageId){
+      case 0:
+        myNex.writeNum("n0.val", dataL[0]);
+        myNex.writeNum("n1.val", dataL[1]);
+        myNex.writeNum("n2.val", dataL[2]);
+        myNex.writeNum("n3.val", dataL[3]);  
+      break;
+
+      case 1:
+        myNex.writeNum("n4.val", dataS[0]);
+        myNex.writeNum("n5.val", dataS[1]);
+        myNex.writeNum("n6.val", dataS[2]);
+        myNex.writeNum("n7.val", dataS[3]);
+
+        myNex.writeNum("n0.val", dataS[0]);
+        myNex.writeNum("n1.val", dataS[1]);
+        myNex.writeNum("n2.val", dataS[2]);
+        myNex.writeNum("n3.val", dataS[3]);
+      break;
+
+    }
+
+
+    myNex.lastCurrentPageId = myNex.currentPageId; // Afer the refresh of the new page We make them equal,
+                                                   // in order to identify the next page change.
+  }
+}
+
+            /*   More for custom protocol and commands https://seithan.com/Easy-Nextion-Library/Custom-Protocol/
+               
+      easyNexReadCustomCommand() has a weak attribute and will be created only when user
+      declare this function on the main code
+      More for custom protocol and commands https://seithan.com/Easy-Nextion-Library/Custom-Protocol/
+      our commands will have this format: <#> <len> <cmd> <id> <id2>
+      and we must send them from Nextion as HEX with the printh command
+      like: printh 23 03 4C 01 01
+
+      <#> start marker, declares that a command is followed
+      <len> declares the number of bytes that will follow
+      <cmd> declares the task of the command or command group
+      <id> declares the properties of the command
+      <id2> a second property of the command
+      
+      When we send a custom command with the above format, the function NextionListen() will capture the start marker # and the len (first 2 bytes)
+      and it will wait until all the bytes of the command, as we have declared with the len byte, arrive to the Serial buffer and inside the timeout limits.
+      
+      After that, the function will read the next byte, which is the command group and the function readCommand() takes over and through a switch command
+      tries to match the _cmd variable that holds the command group value with the statements of the cases.
+      
+      If we do NOT have a match with the predefined, cmd of P for page and T for triggers, it will continue to the default where we store the _cmd and _len to the public variables
+      cmdGroup and cmdLenght as we are going to need access to them from the main code in the next step.
+      
+      Next we call the the easyNexReadCustomCommand() with the precondition and ONLY if we have declared the function in the main code.
+      
+      From this point we can handle the assign of cmdGroup and IDs from the easyNexReadCustomCommand() in the user code, where we can go on with a switch case
+      for the cmdGroup, the one that we have stored the _cmd for public use and we can call it with myObject.cmdGroup. This is why we made cmdGroup a public variable.
+                     */